MORE HUMID MONSOON FLOW TO RETURN THIS WEEK

Quick Update -

A return to an upper air pattern from the southeast is occurring today, which will result in more humidity this week, along with a chance of thunderstorms.

As of Sunday afternoon, the current satellite shows large areas of moisture lurking to the east and south of us.

source: NOAA satellite

source: NOAA satellite

Deep, moist southeast flow is sourcing air masses from Southern Mexico and the Gulf of Mexico. Thunderstorms are beginning to develop in Sonora, Mexico, which will likely help create a shallow “gulf surge” tonight and tomorrow morning. As a result, expect dew points to rise significantly at times the next several days, especially during the morning hours. These will be accompanied by southeast breezes, haze, and more cloudiness.

Dew points in the low deserts will possibly rise into the 70-75 degree range tomorrow morning (and the next several days as well), perhaps even higher. This will shut down the efficiency of evaporative coolers/swamp coolers at times the next several days.

This pattern will bring a chance of thunderstorms, which are capable of producing heavy rain, excessive lightning, flash flooding, hail, strong winds, and blowing dust.

Rainfall chances will be highest in the nearby mountain ranges near Idyllwild and Big Bear, as well as the mountains from Morongo Valley to Joshua Tree.

It is impossible in a convective airmass to know exactly where storms will pop up, so just keep an eye on the sky from Monday through Saturday this week. As always, use common sense around normally dry washes that could be susceptible to flash flooding, especially along highway 62 in the Morongo/Yucca Valley/Joshua Tree/29 Palms corridor.

Be alert to any flash flood warnings issued by the National Weather Service.

Some drying of the airmass is possible around Friday or Saturday of next week, which may limit clouds and thunderstorms to the highest peaks of the nearby mountains.

COACHELLA VALLEY: High temperatures will likely remain in the 105-110 range most of the week, possible rising above 110 around Friday or Saturday if the airmass dries out as expected. Overnight lows will begin to settle into the 80s starting Monday night.

YUCCA VALLEY/JOSHUA TREE: High temperatures will be mostly in the 92-102 range this week, with overnight lows in the 68-78 range. Dew points are likely to be somewhat lower in these areas, mostly peaking in the 50s and 60s.

As always, stay hydrated and avoid excessive outdoor activities during the afternoon hours.

HOT WEATHER HAS ARRIVED - BUT MONSOON PUSH IS WEAK

As advertised, the heat is ON!

Temperatures are well above 110 throughout the low deserts today, with readings in the 115-117 range in many areas such as Palm Springs, Thermal and Imperial. Lows this morning started in the toasty mid 80s. This will definitely help heat our pools up toward the 90 degree mark or more the next few days!

These toasty temps are likely to continue through Monday, with highs between 112-118 the next several days, and low temps in the 80s. The National Weather Service has issued an Excessive Heat Warning as a result, encouraging everyone to stay hydrated and limit outdoor activities. Common sense everyone!

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The National Weather Service satellite image around 4pm shows some cumulus clouds building up over our nearby mountains, as well as over the mountains of San Bernardino County, and the Joshua Tree area.

The areas highlighted in yellow have a very slight chance of a brief thunderstorm (probably less than 15%) before sunset today, and again Saturday afternoon. The airmass is quite dry, so thunderstorms are more likely to be the “dry” variety, with only lightning, gusty winds, and only brief rainfall in limited cores directly under storm cells.

Moisture is a bit more plentiful over Sonora, Mexico, and large thunderstorms are just beginning to erupt there late this afternoon. If these storms are able to continue to expand and spread west, there is a slight possibility they may set us up for a “Gulf Surge” tomorrow morning. Northwest Sonora is prone to large thunderstorm complexes moving west toward the Gulf of California. If they hold together, they will likely trek west and then begin to decay later into the evening with the loss of daytime heating. As thunderstorms decay, they create large areas of descending cool moist air as their updrafts fall apart. Due to the terrain, these outflows tend to push northwest, and pickup additional low level moisture from the Gulf, often transporting it in a shallow layer (maybe 2,000-3,000 feet deep) hundreds of miles to the northwest, into the Imperial County deserts and occasionally, the Coachella Valley. They often take 4-8 hours to arrive here, and bring a short duration of very high humidity, dust and haze, along with southeasterly breezes. It is possible such a scenario could occur Sunday or Monday mornings - but it is completely dependent upon storm formation down in Sonora. It will be interesting to keep an eye on things down there the next few evenings.

Current observations show that the humid airmass, with high dew points at 70 degrees and above, are restricted to areas adjacent to the Gulf of California. Very dry conditions are still found throughout most of the deserts of California, with dew points only in the 40s in most areas.

Current observations show that the humid airmass, with high dew points at 70 degrees and above, are restricted to areas adjacent to the Gulf of California. Very dry conditions are still found throughout most of the deserts of California, with dew points only in the 40s in most areas.

Current satellite image (below) shows the very beginning of thunderstorms blossoming in Sonora, Mexico. IF these continue, we would be more susceptible to a Gulf Surge the next few mornings. Right now, the western extent of upper level moisture (red dotted line) has barely pushed west of our local area.

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COOLING AGAIN NEXT WEEK

Long range computer models indicate a return to more of a “trough" pattern in the Pacific Northwest, which is expected to constrict the high pressure system just a tad to our east. This is more of what we experienced most of May and June. Good news is this means slightly cooler temps for us!

This will allow our brief monsoon switch to southeast upper flow the next few days to return to one from the southwest. This means less afternoon cloudiness, drier air, and a return to more robust afternoon and evening winds along the I-10 corridor (sorry for those on the north side that hate the wind!).

Temps will likely drop back into the 102-108 range later next week, with low temps dropping into the mid to upper 70s. Currently, this “cooler” weather is looking to stick around through the following weekend at this point.

AIR POLLUTION CONCERNS

Air quality the next few days is expected to remain somewhat compromised.

The South Coast Air Quality Management District has issued an OZONE ADVISORY, valid now through next Tuesday, July 19th.

Due to the high pressure system, it is expected to create somewhat stagnant air quality over most of Southern California. Coupled with high temperatures, this increases the formation of Ozone. Unlike other pollutants, ozone is colorless. Therefore, you may peer across the valley with decent visibility, but local air stations are detecting various high levels of ozone contamination today.

source: South Coast AQMD, 7.12.19, 4:45pm

source: South Coast AQMD, 7.12.19, 4:45pm

The South Coast AQMD map above indicates current pollution levels today (as of about 4:30pm) across Southern California. Yellow designates moderate air quality, found mostly in coastal Orange County and Los Angeles Counties. Orange designates “Unhealthy for Sensitive Persons” level of ozone pollution today. Red designates those areas experiencing even worse “Unhealthy Air for All Persons” currently. The areas designated in purple indicate even worse air, designated as “Very Unhealthy for All Persons”.

Currently, the Coachella Valley is experiencing Unhealthy Air for Sensitive Persons. Not far to our west, Very Unhealthy air is found along the west slopes of the San Jacinto Mountains near Idyllwild and Hemet, and further north into the Moreno Valley, Yucaipa, Redlands and San Bernardino area, as well as up into the San Bernardino Mountains, including Crestline and Lake Arrowhead.

This similar pattern is likely to continue the remainder of the weekend.

Drink fluids frequently, consider passing on strenuous outdoor activities through at least Monday, and move into summer mode this weekend as the slow pace of summer is now firmly upon us!

ENJOY THOSE SUNSETS THE NEXT FEW EVENINGS!!!

HOTTER WEATHER AND POSSIBLE MONSOON LATE NEXT WEEK?

The 4th of July is now behind us, and this is the time of year we begin to see intermittent bouts of clouds, humidity and thunderstorm activity when our weather pattern becomes more susceptible to the wind and weather patterns originating to our southeast.

As is typical, Palm Springs often lies close to the boundary of drier and more stable air to our west, originating from the cool waters of the Pacific. However, increasingly strong southeast winds carrying more humid and unstable air from the warm waters of the Gulf of Mexico and Southern Mexico occasionally start to make inroads on our weather. This seasonal shift of wind from the west, to the southeast, is often referred to as the “Summer Monsoon” here in the U.S. Southwest.

Currently, most moisture has remained east of Arizona thus far this summer. Here is a look at todays satellite that exemplifies the pattern of the past month quite well.

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Southwest upper flow circulating around a low pressure system west of Washington has kept temperatures close to normal most of the past few weeks. The high pressure system has remained well east over the Central U.S. and therefore has kept us free of intense heat most of the summer thus far.

HEAT TO BUILD NEXT WEEK - MOISTURE MAY FOLLOW?

The high pressure system is expected to strengthen and move somewhere close to Northern New Mexico or Northeast Arizona toward the middle of next week. If this comes to fruition as is expected, this will cause temperatures to climb over most of the Western United States. Depending on where exactly the high pressure decides to center will determine if we have a moderate heat wave or a major one. Current expectations that temperatures will climb higher but not reach extreme levels. I advise people not to get stuck on the exact temperature predictions this early out as they are still relatively low confidence with the details.

Low Deserts:

High temps the next few days will be relatively comfortable, mostly in the upper 90s - 105 during the day and 68-75 at night.

High temps will likely surpass 110 by next Wednesday or Thursday (possibly even exceeding 115), with low temperatures becoming less comfortable, likely only dropping to 80-85 by Thursday and Friday morning of next week. We may soon see an end to these comfortable mornings lately!

Joshua Tree/Yucca Valley:

Expect temps to be rather comfortable for this time of year, in the high 80s to high 90s the next few days… rising into the mid 100’s by next Thursday or Friday, possibly higher.

MONSOON MOISTURE MAY MAKE AN APPEARANCE

Extended weather models are indicating the high pressure system will likely settle over northern New Mexico and Arizona which is a favorable setup for moisture to finally begin escaping northern Mexico and tracking west into Arizona and eventually, California.

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By next Friday or Saturday, it is likely that the boundary for more humidity, indicated by the red line above, may eventually move west of our area, allowing at least a chance of afternoon thunderstorms to develop.

It is too early to know for certainty, but the pattern shift could suggest we may be vulnerable to southeast wind events, “Gulf surges” of humid and hazy air moving into our area from the southeast, and an increase in overall humidity. Thunderstorms and outflows with dust storms become a possibility under this type of pattern as well.

Therefore, we all need to get out an enjoy the dry and relatively “comfortable” summer temperatures we will enjoy through Tuesday, as it may be replaced by muggy weather by the end of next week!

Hope everyone had a great 4th!!!

HERE WE GO AGAIN...

Memorial Day Weekend is quickly turning blustery and cooler. Yet another system is moving south over California this afternoon, bringing yet another period of high winds, blowing dust, cooler temperatures, and even more mountain snow. Just when you thought it was over….

Lenticular clouds are forming over our mountains this afternoon, ahead of yet another cold front.

Lenticular clouds are forming over our mountains this afternoon, ahead of yet another cold front.

The seemingly unending parade of systems continues its next chapter. This latest system is likely to produce the following weather for the Coachella Valley the next 12-24 hours:

  • Areas of snow above 6,000 feet in the local mountains

  • Another round of unhealthy air quality due to blowing dust and high winds up to 50-60 mph in some areas along I-10

  • Closures possible on Indian Canyon Dr. later today and Monday due to sand and low visibility

Screen Shot 2019-05-26 at 11.48.19 AM.png

Currently, a low pressure system is located over Central California, moving southeast. It will swing east over Arizona and eventually lead to yet another batch of sever weather over the Plains the next few days, exacerbating severe flooding and tornado potential.

WARMER WEATHER IS COMING SOON

For those looking for these abnormally cool temps to end, you will be in luck. A weak trough will linger over the West the remainder of the week, but temps are slowly expected to approach the low end of normal by mid week.

High temps today and Memorial Day will remain WAY below normal, only reaching the high 70s to near 80. However, temps will climb to the low to mid 90s by mid week, with overnight lows mostly in the 60s. There may be some cloudiness in the afternoons and evenings, with a very slight chance of afternoon showers over the nearby mountains at times. For most desert areas though, dry weather is expected from Monday - Friday. Periods of gusty winds are possible at times.

BIG HEAT ANYTIME SOON?

Long range forecast trends indicate the earliest a high pressure system may build over our area is next Sunday or Monday. If this occurs, and that is a big IF…. we could finally see temperatures exceeding 100 degrees. However, at this point, the computer models are not consistent on pushing the low pressure systems away. Let’s see how it goes!

WATER SUPPLIES ARE IN GOOD SHAPE!

The latest data on the reservoirs throughout California (source: California Department of Water Resources) indicate all but one reservoir in the state is far above historical averages. Take a look at the latest graphic indicating how full the reservoirs currently are, and how much above the historical averages they are (BLUE indicates current capacity, and RED indicated % of historical average at the same time in previous years). Keep in mind, they have purposely left some space in the reservoirs to handle continued high runoff that will occur as temps finally begin to increase throughout the high country further north at some point in the weeks to come.

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SNOWPACK CONTINUES FAR ABOVE NORMAL TO OUR NORTH

In the High Sierras, the storm systems have actually added to the snowpack since April, which is unusual indeed. Most areas are 150% to nearly 180% of normal snowpack for this date in May! This will ensure good healthy river flows into late summer. Take a look at the latest graphic from the California Department of Water Resources below:

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PALM SPRINGS - COOL TEMPS FOR MAY

For those following the cool temps of late, take a look how the month has stacked up (Source: National Weather Service):

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The days below normal have outnumbered those above normal, and the cooler temps have been further from normal than the warmer ones. We have at least 2-3 more days below normal, before we begin to trend much closer to normal this week.

Enjoy the Memorial Day holiday everyone!

HERE COMES THE WIND AGAIN.....

The train of storm systems continues across California, with another potent cold front moving into Northern California tonight. The southern end of this system will move into Southern California later tonight , continuing to influence our weather tomorrow. Yet another system arrives Monday afternoon and Tuesday.

I captured this image of a lenticular cloud over the nearby mountains late Saturday afternoon, often a precursor to high winds for our area.

I captured this image of a lenticular cloud over the nearby mountains late Saturday afternoon, often a precursor to high winds for our area.

The deserts can expect periods of high winds to return, with blowing sand and dust likely at times this week. Even a few showers are possible at times. The weather will continue extremely cool, with some days failing to even reach 80 degrees. More details below….

Source: NOAA satellite, late afternoon 5/18/19

Source: NOAA satellite, late afternoon 5/18/19

SATURDAY NIGHT - SUNDAY

As you can see from the satellite image Saturday evening, a powerful storm is moving east into California. A low pressure is centered off the Northern California coast, with a cold front curling southwestward off the coast. This is a significant system for this time of year, and is expected to drop more than 1-2 foot of snow in the higher elevations of Central California the next few days.

For us here in the Palm Springs area, the approaching low pressure will begin moving inland to our north. As the pressure drops over Nevada tonight, this will increase the onshore flow of air, and winds have already begun to increase in some areas. This is expected to continue tonight, with strengthening winds by tomorrow.

Various area are likely to see winds tonight and tomorrow. Along the I-10 Corridor, as well as northern areas of Palm Springs and Rancho Mirage, northwest winds are likely to gust between 30-35 tonight, with gusts likely increasing to 50 mph+ by late Sunday morning into the late afternoon or evening. Blowing sand is likely again, for continued issues for roads crossing the Whitewater Wash.

Also, the remainder of the areas in Central and South Palm Springs, as well as South Cathedral City, South Rancho Mirage and South Palm Desert, are likely to have periods of strong winds from the south and southwest at times, becoming more frequent and stronger on Sunday. Gusts may reach 30-45 mph Sunday.

WHERE WILL IT RAIN/SNOW?

Cirrus clouds are already creating an opaque sky, and these clouds will continue to thicken and lower overnight. By tomorrow, thick cloudiness is likely to be banked against our western mountain peaks, as rain and snow begins in the nearby mountains. Snow level will start around 7,500 feet Sunday morning, lowering to near 6,000 feet by late in the day.

By Sunday night, the snow level may lower to near 5,500 feet, with 3-7 inches of snow possible above 7,000 feet.

For the deserts, not a lot of rain is expected in the low deserts of the Coachella Valley. Expectations are that less than 0.05 inch will fall, so some areas may possibly remain dry, with others susceptible to brief showers or even a stray thunderstorm Sunday. However, in the higher desert communities such as Morongo Valley and Pioneertown, up to 0.25 inch is possible on Sunday and Sunday night. The further away from the higher peaks you move east, (i.e. Landers and Twentynine Palms) will likely receive lesser amounts. However, the big story will be the wind… with gusts near 50 mph expected in most high desert areas, with areas of blowing sand and dust possible.

ANOTHER SYSTEM MONDAY AFTERNOON - TUESDAY

After a short break from the wind and clouds late Sunday night and early Monday, yet ANOTHER system is expected to dive south into the West later Monday into Tuesday. This system has the potential to be stronger, with even higher winds and possibly more mountain snow and lower elevations scattered showers. Winds may gust up to 65 mph at some point Monday night or Tuesday. This system has the potential to stall out over the Desert Southwest for several days, as it slowly weakens. Scattered showers or even a thunderstorm may linger through Wednesday or Thursday if the system stays nearby. All this wind will cause havoc for efforts to keep the roads between I-10 and Palm Springs open. Be prepared for closures at times.

7 DAY PRECIPITATION ESTIMATES

The National Weather Service is predicting some areas of California may receive over 2-3+ inches of rain the next 7 days. The deserts won’t get all that much, if any…. but the nearby mountains and coastal areas from San Diego, northward to Oregon, are expected to get several periods of late springtime rainfall. Take a look at the latest charts they’ve released below.

Nearly the entire West will get a nice soaking at times the next 7 days, according to the latest National Weather Service predictions.

Nearly the entire West will get a nice soaking at times the next 7 days, according to the latest National Weather Service predictions.

WHAT ABOUT THE COOL TEMPS?

Temperatures have been on a rollercoaster this month, oscillating back and forth between above normal and below normal. Take a look at the high and low temps at Palm Springs Airport thus far this month. Those marked in blue indicate the days with below normal temps, and those marked in red indicate above normal temps. I’ve indicated how many degrees above or below normal in the column to the right.

Source: National Weather Service, Palm Springs Airport.

Source: National Weather Service, Palm Springs Airport.

Perhaps what is so remarkable is the lack of excessive heat. Eight days of the month have been above normal, yet only one day has reached 100 degrees thus far. There remains a decent chance that we will not see temperatures approaching 100 degrees for the remainder of the month. In fact, some areas the next several days may experience record low temperatures. Some mountain areas will likely approach 35 degrees below normal! Late springtime storm systems aren’t entirely out of the question, but what is remarkable about this pattern, is the consistency with which continued systems are arriving.

SUMMARY OF WEATHER TO WATCH THIS WEEK

HIGH WINDS: Saturday night, Sunday, Monday, Tuesday, ( less widespread Wednesday, Thursday and Friday)

RAIN: Slight chance of desert showers or thunderstorms Sunday, and again Monday-Tuesday. Slight chance Wednesday or Thursday.

MOUNTAIN SNOW: possible later Sunday, and again later Monday-early Tuesday, mostly above 6,000-7,000 feet.

POTENTIAL PROBLEM AREAS:

  • Highway 243 near Idyllwild will experience periods of thick fog. Snow level may lower enough for a few flakes north of Idyllwild near Pine Cove, perhaps Sunday evening, and again Monday night.

  • I-10 from Banning to Indio will experience periods of heavy winds, between 40-65 mph at times this week, likely causing blowing sand and dust during windiest periods and creating reduced air quality for the central and eastern portions of the Coachella Valley due to airborne dust.

  • Highway 62 from I-10 to Twentynine Palms will experience periods of heavy winds, between 35-60 mph at times through Wednesday, with blowing sand and dust during windiest periods.

  • Highway 18 from Running Springs to Big Bear and Highway 38 from Angelus Oaks to Big Bear may experience a few periods of snow accumulation, possibly Sunday night and again Monday night or early Tuesday.

  • Indian Canyon Rd, Gene Autry Trail, and Vista Chino are all going to be susceptible to road closures due to poor visibility and excessive blowing sand and dust at times (Indian Canyon is highest risk).

MUCH COOLER TEMPS (PALM SPRINGS):

  • Sunday: 77/56

  • Monday: 80/57

  • Tuesday: 76/57

  • Wednesday: 77/57

  • Thursday: 82/61

MEMORIAL DAY OUTLOOK

Long term outlooks are always a bit difficult to have much confidence in, but current projections show an area of low pressure remaining over the West for the holiday weekend. This would suggest temps will likely remain at or below normal, depending upon how far south the systems linger. Currently, temps somewhere between the high 80s and mid 90s seem most likely. It will likely be another 3-4 days before the details will become clearer looking that far ahead.

Interesting to note, is that the persistent low pressure over the West appears to be balanced by persistent high pressure over the Southeast United States, effectively stalling the normal movement of systems from west to east. This is likely to cause an early season heat wave in portions of the Southeast, with temps likely to approach 100 degrees.

Enjoy the cool weather while it lasts! I know many people are seriously DONE with this wind and cooler weather, but we will undoubtedly get our high heat at some point soon.

CONSIDER AVOIDING MAJOR TRIMMING OF HEDGES AND TREES AT THIS LATE POINT IN THE SEASON

Remember to use caution over trimming hedges and other trees/plants this late in the season, as recently cut ficus hedges and trees and shrubs have historically been shocked when temps climb over 115 the last few weeks of June. Giving overly manicured vegetation that is trimmed now, only 2-3 weeks to heal up before our high heat arrives, has proven to assist in the death and shock of many of our plants! Do yourself a favor and ask your landscapers that haven’t yet learned this, to refrain from excessive trimming at this point, until late September! You will thank me later for the advice! Too many plants go into shock late next month (if we get the extreme heat), if they’ve been severely pruned the last half of May.

UNUSUAL STORM SYSTEM EXPECTED THIS WEEKEND

A relatively unusual storm system is developing over the Southwest U.S. the next few days. This storm is moving in from the northeast - We typically only see systems from this direction a few times each year. This system may bring:

  • Slight chance of scattered showers and thunderstorms

  • Slight potential for flash flooding, especially higher desert areas and mountains

  • Thunderstorms could contain high winds, blowing dust and even hail

Computer models have been trending toward the development of a low pressure system over our area all week. As of Thursday afternoon, these trends have proven reliable, as recent satellite imagery shows upper winds blowing from the north/northeast over Northern California today, as a low pressure system is developing and strengthening over Nevada today, moving southwest toward Southern California.

Satellite Source: NOAA

Satellite Source: NOAA

In the graphic above, the green solid lines represent the upper level jet stream winds. The wild pattern indicates winds being forced north, then back east and south, around a strong high pressure system anchored off the coast of Oregon and Washington. This high pressure is causing the winds to dive south and southwest over the back side of the high pressure system, and leaves the entire Western U.S. susceptible to storm development, as several low pressure systems have continued to form over the Idaho/Utah area and have moved southwest toward our area.

The latest system is forming this afternoon over Western Nevada, and is expected to continue moving southwest to a position to the west of Santa Barbara by Friday. It will continue to move south off the coast later Friday, and is expected to slowly start moving east over the San Diego area Saturday and into Arizona on Sunday.

Since we are now approaching mid-May, we are experiencing a much higher sun angle, resulting in more daytime heating than what we see earlier in the year. This heating will allow the atmosphere to become increasingly unstable over the next 4-5 days. Combined with the dynamics of the low pressure system moving over our area, it is likely to produce periods of scattered showers and possible thunderstorms.

This is NOT a monsoon pattern of wind and moisture from the southeast that hits during the summer, but is instead due to atmospheric forcing, and instability (colder air aloft, near the low pressure system, but warmer surface temps), allowing showers and storms to develop.

It will be impossible to accurately predict exact rainfall amounts between today and Sunday, but the latest computer models are indicating the possibility of as much as 2 inches of rain over the nearby mountains, with lesser amounts over the deserts.

Map Source: Google

Map Source: Google

Most of the Coachella Valley is expected to see 0.15” - 0.5” between today and Sunday, with amounts closer to 1” likely in the higher terrain south of the Yucca Valley/Joshua Tree area, as well as closer to the mountains on the west side of Palm Springs and up in the Banning/Cabezon area.

HOWEVER, it is likely that some areas may see locally higher amounts, close to any heavier thunderstorms that have the possibility of forming. Currently, the weather models predict the highest chance of heavier rains and thunderstorms is Saturday afternoon. Regardless of that, scattered storms are still possible anytime from later today through Tuesday afternoon, especially in the afternoon and evening hours. It will be important to keep an eye on the sky, and be alert for any threatening storms.

Rainfall of these amounts in a quick period of time can cause washes to suddenly fill with mud and water. Anyone near hiking trails or creeks the next 4-5 days should pay attention for any flash flood watches or warnings, should the National Weather Service issue any. Roadways in the Joshua Tree area are particularly susceptible to sudden flooding.

If more than 2 inches of rainfall occurs in the nearby mountains, it is possible that the Whitewater River could flow for a brief time over Indian Canyon Dr. south of I-10. It’s too early to predict if this will occur, but it is certainly worth mentioning, since springtime systems are unpredictable.

UPCOMING WEEK STARTS AND ENDS UNSETTLED

The weather pattern is expected to remain slightly unsettled Monday and Tuesday of next week, with isolated afternoon and evening showers and thunderstorms possible. Mountainous areas have the highest probability of receiving rainfall, which is likely to be widely scattered.

Wednesday and Thursday should return to fair and dry weather, with a warming trend. Windy weather is possible along the I-10 corridor and also into the high deserts, with local blowing sand and dust possible..

Friday through Sunday is likely to cool down once again, with gusty winds, blowing dust and even the slight possibility of showers returning to the mountains at some point. Future weather model runs will need to be watched to see if another system enters our area the following weekend or not. Current trends are indicating this is a possibility. Either way, May is typically one of the driest months here in the desert. If this rainfall does materialize as expected, it will be very anomalous.

CLIMATE STATS

Taking a look at the National Weather Service Data at Palm Springs Airport….

May 8 - Hi/Low: 85/63 (Normal is 91/63)

**Last year, May 8 - Hi/Low: 108/69 (we’ve been fortunate not to experience this high heat this year thus far!)

Rainfall since October 2018: 7.76 inches (Normal is 4.68 inches)

High temps the next 5-7 days should remain at or below normal most days, in the 80s and 90s, with lows in the high 50s and 60s most nights. Temps should be very comfortable!


Use caution and watch for weather warnings the next several days, if heavy rains do in fact develop. Otherwise, we will be treated to some fantastic cloud formations and skies during the next several days!

DUST, CHANGING TEMPS, AND A CHANCE FOR RAIN?

Springtime is in full swing here in the desert. Typically, that means we are in store for wildly fluctuating temperatures and a lot of wind, and this spring has been no different. However, this spring has been particularly dusty, with even modestly windy days creating reduced visibility.

FREQUENT DUSTSTORMS THIS SPRING

Each time the winds gust above about 25 mph, the skies along the I-10 corridor have been clouding up with dust this spring. If the winds increase over 35 mph, excessive sand begins blowing across roads. There have been several stories in local media recently discussing the challenges with frequent road closures due to blowing sand (and water during severe storms) along Indian Canyon Dr, as well as less frequent closures on Gene Autry Trail and Vista Chino. There has been a lot of chatter about what the city could do. Building a bridge, which recent estimates place OVER $200 MILLION, is clearly not an affordable option.

As the various leaders attempt to come up with viable engineering solutions, it is a good moment to understand what scientific processes are at work to create these problems in the first place.

Let’s take a look from the air first. Here is the satellite view of the Whitewater River wash as it crosses Indian Canyon Dr, south of the I-10 interchange (courtesy of Google Satellite).

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Indian Canyon Drive is located on the right side (above), and the area of most concern is highlighted by the red rectangle. The dotted red lines indicate the approximate boundaries of where the water flows during extreme rainfall events, like those we experienced several times this past winter. The normally dry wash fills with water and soil during those events. On the left side of the photo, the blue arrows represent the Whitewater River flowing southeast. The greenish colored rectangular shapes in the center of the image are the water retention basins, where the normal Whitewater River flows are diverted, to allow ground water to sit in these basins, and slowly seep down into our underground aquifers. Only during periods of high runoff does the river flow past the retention basins, and southeast across Indian Canyon Dr. down valley toward Indio and the Salton Sea.

IT’S AN UPHILL BATTLE - LITERALLY!

To fully grasp the magnitude of what engineers are up against, it is important to look upstream from Indian Canyon Dr…. to see where the source regions are for the sand, silt and water that flows downstream. Here’s another expanded Google Satellite view, below.

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As you can see, there are several creeks and rivers that flow out of the nearby mountains. The areas outlined in the red dotted lines indicate the larger creeks and riverbeds. While our average annual rainfall in Palm Springs is typically less than 6 inches, the nearby mountains receive more than 35-40 inches. This past winter, even more than that has fallen on the middle slopes (with an extensive snowpack at higher elevations). The areas outlined in the solid yellow lines are sand dunes. It’s easy to miss these while driving along highway 111, but these areas capture an enormous volume of sand as the strong prevailing winds blow from the west, through the San Gorgonio Pass. Recent high water flows supplied these areas with a fresh inventory of silt, sand and dirt.

EXTREME RUNOFF AND DEBRIS FLOWS: MORE DUST!

As mentioned above, the high rainfall and runoff this past winter has led to a fresh supply of dirt, sand and silt into all the river systems to our west. While local officials can use bulldozers to clear the roads after a specific high wind event, they are up against at least 15 miles of dirt, sand and silt that will slowly track to the southeast over time. In the spring and early summer, it is quite common to have very strong west and northwest winds blowing through the San Gorgonio Pass. Nature will continue to push sand and silt our way.

Because of the high supplies of dirt and sand, visibility has been reduced many days this spring thus far due to airborne dust and sand. In years past, typically it would require winds over 35 mph to begin causing areas of blowing sand and dust. However, this year, even winds under 30 mph have been able to generate dusty condition. Even those areas outside the normal wind belts feel the effects of this. Most of us have noticed a fine layer of dust on our cars left outside, even if the winds in our particular neighborhood have remained calm. Being downwind, the normally calm areas have experienced higher levels of dust settling as the fine dust particles that blow high into the air near the I-10 corridor eventually come settling back down to the earth further to the south and east.

Sorry for the bad news, but dusty and sandy conditions are likely to continue into early summer!

UPCOMING WEATHER CHANGES: COOLER, WINDY AND POSSIBLY WET?

Getting back to our upcoming expected weather - we have a few interesting weather changes to keep an eye on the next 7 days.

Heat will continue through Saturday, with high temperatures in the low 100’s (90-94 in the Joshua Tree area). This is close to record breaking heat for many communities.

By Sunday, an approaching system will bring slight cooling, down into the 90’s (low 80’s Joshua Tree).

Monday will see partly cloudy skies, and even a chance of scattered showers and thunderstorms, as well as increasing winds Monday and into Tuesday. Temperatures will likely cool into the 80’s for Monday - Wednesday (low 70’s Joshua Tree). A low pressure system will pass through our area, creating an unstable airmass and the possibility of storms. Storms are likely to be scattered, meaning many locations will likely remain dry. Low pressure systems this time of year are erratic and difficult to pinpoint this far ahead.

The extended weather pattern suggests the remainder of next week we will be susceptible to small disturbances from the northwest, as well as periods of wind, most likely on the north end along the I-10 corridor, and in the high deserts from Morongo to Joshua Tree. Highs will likely juggle between the 80’s and 90s (with 70s and 80s in the Joshua Tree area).

LOW SNOW LEVELS EXPECTED TONIGHT AND TOMORROW

As cleanup from the recent devastating storm continues to commence, a new storm system is taking aim on the Palm Springs area tonight and Thursday. This storm is not expected to create extreme rainfall amounts, but it will be memorable in that it may be the coldest storm of the season thus far. We will likely see a slow warm up into next week (although that is somewhat questionable), with more storms possible on the horizon after March 1st. More on that shortly.

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As of late Wednesday afternoon, the next storm is seen developing over Southern Oregon (source: NOAA). It is expected to move south to over Southern Nevada by Thursday afternoon.

LOW SNOW LEVELS AND POSSIBLE ROAD CLOSURES

This storm is likely to bring snow to low elevations. Here is the best guess at this point over the next 2 days:

  • Wednesday Night: 3,500 feet, likely dropping to 2,500 - 3,000 feet by morning

  • Thursday: likely around 2,500 feet, locally lower in the morning (most widespread)

  • Thursday Night: likely 2,000 - 2,500 feet (less widespread)

Small fluctuations in the snow level could have dramatic effects on nearby roadways. Here is a list of roadways potentially impacted by snowfall the next 2 days:

Highways in red could potentially experience snowfall late tonight through Thursday night.

Highways in red could potentially experience snowfall late tonight through Thursday night.

Highway 74 and 243 in the Garner Valley and Idyllwild area are most likely to see heavy snowfall. Highway 62 through the Yucca Valley area is also likely to see a dusting, with perhaps a few inches likely. Even I-10 near Banning and Yucaipa could possibly see a light dusting. If the snow level drops slightly more than expected, it’s possible more snow could fall. Be prepared for major travel disruption if this occurs.

Further away, I-15 south and north of Las Vegas is expected to receive at least 1-2 inches of snow, perhaps even more, sometime between Thursday morning and Friday morning. This could greatly impact travel along the interstate. Also, I-40 from near Kingman to Flagstaff is expecting 6-8 inches near Kingman, and over a foot near Flagstaff.

Here is the latest predictions for precipitation amounts in various areas. Keep in mind, these are estimates. Due to the convective nature of this storm, some areas will likely receive lesser amounts, and others may see higher totals.

  • Palm Springs areas: 0.1 - 0.4 inch rain, perhaps more in scatted thunderstorms and closest to the mountains

  • Morongo Valley: 0.25 - 0.5 inch of rain (possibly mixed with snow in foothills and eastern portion)

  • Yucca Valley: 0.25 - 0.4 inch of rain - likely switching to snow, with trace - 4 inches possible, highest toward the southern foothills and toward the top of the Morongo Grade

  • Joshua Tree: 0.1 - 0.4 inch of rain, possibly switching to snow with trace - 2 inches of snow possible in town, and perhaps mostly snow in the national park, with 2-6 inches possible at higher eleveations

  • Pioneertown: 0.25 - 0.4 inch of rain, with a switch to snow likely (2-5 inches possible)

  • Landers/Lucerne Valley: 0.1 inch of rain, with a switch to a few snowflakes possible in higher areas, mostly toward Lucerne Valley

  • Big Bear: All snow, 6-12 inches possible, with 20 inches or more at ski resorts possible

  • Idyllwild: All snow, 6-15+ inches possible

  • Julian: 8-14 inches of snow possible

Best thing to remember for this storm is that snow may fall in areas it doesn’t fall very often. A scattered thunderstorm could also briefly allow hail or graupel to fall at lower elevations, mostly Thursday afternoon and evening. Intense, widespread flooding rains are not expected, even if a scattered storm creates brief heavy rainfall in a specific area.

BRIEF WARMING POSSIBLE NEXT WEEK?

Yes! For those that want to shed a few layers, we may actually approach or even exceed 70 degrees next week! However, the computer models are all over the place about just how warm it may get, so it’s unclear if 68 is the highest we get, or if we may be graced with high temps in the mid 70s. I’m certainly ready for some 70s again!

STORMS LURK ON THE HORIZON THOUGH….

Long range computer models show a shift in the weather pattern sometime close to or after March 1. Instead of storms diving down from the north and northwest, like what is expected tomorrow, the storm track is showing indications of becoming more zonal, allowing a more west to east trajectory. This type of pattern usually allows snow levels to be somewhere around 6,000 feet. It also will allow storms to pick up greater moisture from the subtropics, allowing for heavier rainfall totals. Some indications show California could be hit by several more “atmospheric river” events like the one that brought heavy rain several days ago. It is too early to predict exactly what will come of this next weather change, but it is HIGHLY SUGGESTED to be sure you take advantage of the fine weather this upcoming weekend to clear out any drains and yards that need them after the recent storms.

RAINFALL AND TEMP STATS - Palm Springs Airport

Rainfall since October 1 (start of annual season): 7.21 inches (normal is 3.50). We are 3.71 inches above normal.

Rainfall for February: 4.25 inches (normal is 0.65 inches). We are 3.60 above normal for the month.

Normal high and low: 73/49. Yesterday, the high/low was 60/39.

(Source: National Weather Service)

It isn’t likely Palm Springs will see any snowfall the next 2 days, but the nearby mountains will get another impressive dump! Enjoy the sights, and use caution if you are traveling in the snow!

MAJOR STORM BEGINNING TO DEPART - EXTENSIVE DAMAGE REPORTED

The well advertised “atmospheric river” took aim at Southern California last night and today, bringing in high levels of moisture from the subtropics. A low pressure system paired up with this moisture, and the combination has brought excessive amounts of rainfall to most areas of the state today. Flooding has been reported in many areas, with dangerous traveling conditions.

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GOOD NEWS FIRST….

Thankfully, the moisture plume is advancing east, and will be leaving our area within the next few hours. Skies may become partly cloudy before sunset, with most of the heavy rain likely ending. A few scattered light showers are possible tonight and Friday (and again Sunday), but those should mostly be confined to the nearby mountains and also in the higher desert areas near Pioneertown, Morongo Valley, Yucca Valley and Joshua Tree. Widespread torrential rains are NOT expected tonight or tomorrow.

HOWEVER, in the meantime, it may take several days or more for many of the flooded washes to dry up. It will also take awhile for roads to be cleared. More on road closures in a moment.

WHAT HAPPENED TODAY?

A plume of very moist air from northeast of Hawaii combined with a potent low pressure system, which took aim directly at Southern California today. A very strong storm earlier in the week struck the Hawaiian Islands with destructive winds, high surf and even snow down below 7,000 feet. This was a rarity for Hawaii. This storm tapped into moist air from the tropics, and the air circulation patterns around the low pressure system carried the moist air to the northeast. The “perfect setup” occurred, as this moisture combined with a low pressure system moving southeast off the coast of California. This formed a relatively narrow “river” of moist air that hit Southern California, mostly between about Big Bear on the north, and San Diego on the south.

Since the air mass associated with this system originated far to our south, the snow level rose all the way up over 10,000 feet today. This meant all the precipitation fell as rain, even up most of the nearby mountain slopes. The already heavy rainfall fell atop a heavy snow pack, and added to the extreme amount of water flowing off the nearby mountains. Mt. San Jacinto has already reported over 9 inches of rain since last night, which is why the rivers flowing off the mountain are nearly overflowing.

Rainfall totals in the Palm Springs area have averaged 2-4 inches, with 1-2 inches in the Yucca Valley and Joshua Tree area, and around 1 inch in the east valley areas. Here’s a map from the National Weather Service, as of about 1 pm. These numbers will likely rise a bit as the rain is still falling in some areas. Clearly, today’s deluge hit the mountains hardest, with most areas picking up 5-9 inches overnight.

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Todays extreme weather has caused major travel headaches in our region as well. As best I have been able to assess today thus far, the following roads are either closed, or have been closed at some point today:

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  • Highway 111 at Windy Point (rockslide, between PS and I-10)

  • Golf Club Drive at the wash, north of highway 111 (Palm Springs/Cathedral City)

  • Cathedral Canyon Rd, north of Perez Rd (Cathedral City)

  • Frank Sinatra, just east of highway 111 (Rancho Mirage)

  • Country Club Dr, just east of highway 111 (Rancho Mirage)

  • Fred Waring, east of Portola (Palm Desert)

  • Indian Canyon Rd, between I-10 and Palm Springs, at the wash

  • Gene Autry Trail, between I-10 and Vista Chino, at the wash

  • Vista Chino, at the wash, just east of Gene Autry Trail (Cathedral City)


ADDITIONAL CLOSURES

  • Highway 243 closed both north and south of Idyllwild. The road has been washed out in several locations, effectively cutting off Idyllwild today

  • Highway 74 from east of Hemet to Mountain Center and near Lake Hemet

  • Highway 18, west of Big Bear, due to landslides

  • Several roads in the Yucca Valley area have experienced closures, including Paxton Rd between highway 247 and Balsa, as well as India Ave between Barron Dr and Nelson

IMAGES FROM TODAY

Whitewater River in Palm Desert at Monterey Rd.

Whitewater River in Palm Desert at Monterey Rd.

The Araby Wash at highway 111, nearly rising up to the top of the ledges.

The Araby Wash at highway 111, nearly rising up to the top of the ledges.

Highway 243 near Lake Fulmor, in the Idyllwild area, has been washed out.

Highway 243 near Lake Fulmor, in the Idyllwild area, has been washed out.

OUTLOOK

Several weaker weather systems are expected to pass through Southern California the next 5 days. The next appears late Friday and Friday night, then again Sunday. Both systems are not expected to be major rainfall producers for the deserts. However, they may drop light rain at times, and may increase the winds as well. Temperatures will be chilly over the weekend, and lowering snow levels will make snowfall likely once again in the mountains. Lowering temperatures will likely lead to icing of leftover water above about 4,000 - 5,000 feet, adding to cleanup challenges in the Idyllwild and Big Bear areas.

Stay safe out there, and stay tuned to additional road closures. I’m sure the brave people employed to clear our roads will be doing their best to help return travel patterns to normal over the course of the next 7 days! They will have their hands full!

Storm Rolls Through Santa Barbara and Ventura - Currently Heading East into LA...

11:30 am Update 2/2/19

The cold front is moving east into the Los Angeles area currently. A squall line has set up, with a band of extremely heavy rain and wind gusts approaching 50 mph. Ahead of this line of stormy weather, the wind is blowing from the southeast. Rainfall rates within the narrow squall line have been as high as 0.50 inch in 10 minutes time, indicating blinding rainfall. Fortunately, the squall line is rather narrow, and rainfall rates quickly are diminishing to heavy, but not torrential levels, once the band moves east. The winds quickly switch to the southwest behind the squall line.

Notice the narrow, wavy dark green band indicating the “squall line” as of 11:15 am.

Notice the narrow, wavy dark green band indicating the “squall line” as of 11:15 am.

A closer look at the wind observations shows this squall line is the intersection of the wind shift from the southeast to the southwest.

Wind gusts are noted in red.

Wind gusts are noted in red.

This cold front is moving east into LA, San Diego, the Inland Empire, and the San Diego areas. Those areas will experience increasingly heavy rainfall and increasing winds. As the squall line passes through, it will provide a short period of perhaps 10-20 minutes where rainfall rates will become extreme, with low visibility and suddenly increasing winds to over 40-50 mph. As the squall moves east, rainfall rates will likely diminish somewhat, and winds will shift and slowly diminish about a half hour later.

Estimated progression of the wind shift and squall line to the east the remainder of the afternoon.

Estimated progression of the wind shift and squall line to the east the remainder of the afternoon.

Based on the current forward speed, this wind shift should hit the deserts somewhere close to 3:00 - 4:00pm this afternoon.

Due to the terrain, it will not likely be as dramatic as what is being experienced in the coastal areas. Flash flooding has been reported in many areas of Santa Barbara, Ventura and LA Counties.

However, it is likely that rainfall rates will increase in the deserts between 2:30-4:30pm. Also, when winds shift to the southwest, it is possible that some sections of the Coachella Valley will become very windy for a few hours.

Thus far, the Coachella Valley has had winds mostly under 10 mph. Some southeast winds approaching 25 mph have been blowing in the far east valley near the Thermal and Coachella area.

In the Yucca Valley, Landers and Joshua Tree area, winds have been stronger, as was expected. As of just before 12 noon, here’s a map of the wind gusts (in red, below) for those areas. Notice that the Burns Canyon site on the north slopes of the San Bernardino Mountains has a current gust to 63 mph. Gusts there have been between 60-80 mph most of the morning. A bit lower in elevation, the Landers and Yucca Valley area have begun to see winds increase into the 40-50 mph, as have higher peaks within Joshua Tree National Park. As the cold front approaches, it is likely these areas will continue to see widespread high winds the remainder of the afternoon as well.

Current wind gusts (in red) as of about 11:45 am.

Current wind gusts (in red) as of about 11:45 am.

EXPECTED IMPACTS TO THE COACHELLA VALLEY

As the cold front moves into our area, it is largely expected that nuisance flooding of roads and intersections is likely. As the rains continue into the night, most of the area washes are expected to begin swelling with water, with many of the usual wash crossings running the risk of closure due to high water flows. POSSIBLE ROAD CLOSURES for tonight and Sunday are noted in RED below, including Indian Canyon south of I-10, Gene Autry Trail south of I-10, and Vista Chino east of Gene Autry Trail, as they cross the Whitewater Wash.

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In addition, Golf Club Drive north of highway 111 and Cathedral Canyon Rd north of Perez Road can sometimes experience water across the roadway in the Cathedral City area where the roads cross the Whitewater River. Also, Dinah Shore can experience some short term flooding west of Cathedral Canyon Rd during a heavy rain event. The areas outlined in RED (below) indicate the areas to be on the lookout for water and potential flooding or road closures the next few days.

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MORE STORMS LINED UP

Additional rainfall is likely Sunday through Tuesday, although rainfall amounts in the deserts are not anticipated to be as significant. Mountain areas will see snowfall pile up the next several days, especially in the Big Bear area, as indicated in the previous reports. Anyone traveling to the High Sierra should consider postponing their travels as well. Mammoth is expected to receive 5 feet of snow in town the next few days, with 10 feet up on the ski summits. Lake Tahoe is also expected to receive 2-4 feet in town and 5-8 feet up on the slopes. This will make travel impossible at times along I-80 and US-395 in various locations the next several days.

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Enjoy the rains, and watch for any weather warnings via the National Weather Service the next several days.

ANOTHER STORM ON ITS WAY

The next in a series of storms is forming off the coast of California, ready to move onshore over the weekend. This storm is larger than many we’ve seen this winter, and has significant pressure gradients in place to produce potentially damaging wind gusts to many areas of California on Saturday.

Here’s an image of the enormous storm forming off the coast of California as of 11am Friday (image courtesy of NOAA).

Here’s an image of the enormous storm forming off the coast of California as of 11am Friday (image courtesy of NOAA).

However, as is always the case, forecasting exactly which areas of the Coachella Valley will experience winds with this next system is going to be difficult. We definitely will experience rain however, so that portion of the forecast is less in doubt.

HIGH WINDS

At this time, after examining the various weather models, it appears the best chance for damaging winds will be in the mountains, and the north slopes of the San Bernardino Mountains. South winds could exceed 80 mph in some of those areas. Highway 18 from Big Bear to Lucerne Valley could be particularly vulnerable to damaging winds. Pioneertown and North Landers may also see extreme gusts. These winds are likely to be strongest from about 9 am - 4 pm Saturday.

Slightly weaker, but still strong winds up to 40-50 mph or more are likely in the remainder of the high desert areas, including Yucca Valley, Joshua Tree, 29 Palms, Victorville, Apple Valley, and the Barstow area.

Winds for the Coachella Valley are a bit more difficult to predict. Winds for most of Saturday are expected to blow from the south and southeast. This is usually an unfavorable direction for high winds in the Coachella Valley, as the topography of the nearby mountains typically blocks most of the wind from surfacing. However, due to the incredible dynamics associated with this incoming storm system, it is certainly possible high winds will occur at times Saturday afternoon, especially along the southern foothills, including South Palm Desert, South Rancho Mirage near highway 111, Cathedral City Cove, as well as the Araby and Indian Canyons area of South Palm Springs.

As the powerful cold front approaches late Saturday afternoon, winds are expected to shift to the southwest and west. During this time period, which is currently expected between about 2 pm and 7 pm Saturday, would be the most likely period of severe winds in the Coachella Valley, if they occur. Winds may also begin to crank through the I-10 corridor as well, where we may have northwest winds blowing along I-10, into the northern areas of town…. and we concurrently have southwest winds blowing along the southern areas along the 111 corridor from Palm Springs to Palm Desert. It’s a tough wind forecast, but the takeaway is that winds in some areas will be strong, whereas other area may be protected. My best advice is to prepare your yards for the worst, but don’t be surprised if the wind doesn’t blow much in any one spot.

As a sidenote, high winds are expected in the coastal and valley areas of the rest of Southern California. Anyone traveling into San Diego, Orange County, the Riverside area, Los Angeles, Ventura, Santa Barbara and up into the rest of Central California should be prepared for the possibility of high winds, downed trees and power outages Saturday afternoon in those areas most exposed to high winds from the south. I-5 over the Grapevine and US 101 will be particularly at risk.

RAIN AND SNOW SATURDAY AND SUNDAY

Heavy amounts of rain will fall in many areas of California, with heavy snow in the mountains. Flash floods and mudslides are likely in many areas, especially the burn areas from the last several years. Malibu, the mountains of Orange County, and the Santa Barbara area need to be prepared for possible damage.

The Coachella Valley will have varying amounts of rain, mostly between 0.40 - 1.25 inch for Saturday and Saturday night. This will likely be enough to get the washes running for a day or two, so it is possible that Indian Canyon and Gene Autry Trail may be closed for awhile at the wash. Some water could fill the Araby wash as well by late Saturday or Sunday, and the Tahquitz Creek will likely see renewed flow increases.

The nearby mountains will see varying amounts of snow. For elevations above 8,000 feet, 1-3 feet of snow is possible this weekend. Lesser amounts will fall between 7,000 - 8,000 feet, with several inches possible from 5,000 - 7,000 feet. Weaker systems are expected to come ashore Sunday, Monday, and again Tuesday evening… which is likely to drop several more inches of snow on top of that which falls Saturday and Saturday night with the main storm. However, the unsettled weather Monday - Wednesday is likely to hover over or west of the mountains, but the deserts will likely remain partly cloudy and cool, with only a slight chance of scattered showers predicted for Monday - Wednesday.

EXTENDED FORECAST

The extended forecast currently shows dry and slightly warmer weather returning for Wednesday - Friday, with highs likely staying in the 60’s. Some breezy north winds are possible at times.

The long term models are hinting at the dry weather continuing next weekend, before possibly turning unsettled yet again sometime after February 6-8th, for yet another period of wet weather for the state by the middle of the month a distinct possibility.

SUMMARY

Here’s a list of the current watches/advisories and warnings for the upcoming weekend:

  • Wind Advisory for the Coachella Valley, Yucca Valley and 29 Palms areas for Saturday: winds may gust to 45-50 mph as the cold front passes through, especially between 2-6 pm. Some areas may not experience high winds that are sheltered by nearby mountains, however.

  • High Wind Warning for the mountains, and the high deserts for Saturday: winds may gust to 80 mph in the higher mountains and also on the north slopes of the San Bernardino Mountains, including Apple Valley, Lucerne Valley and the Victor Valley.

  • Winter Storm Warning for the mountains: Up to 2 feet of snow above 8,000 feet, and 4-12 inches between 6,000 - 8,000 feet between late Saturday afternoon and Sunday afternoon. Snow level will drop from 7,500 Saturday to 4,500 feet by Sunday. Additional snow may fall Monday through Wednesday morning.

  • Flash Flood Watch for the lower elevations of the mountains, and the coastal areas of Southern California from Orange County to Santa Barbara, including LA, OC and the Inland Empire. Intense rainfall rates may cause flash flooding on Saturday and Saturday night. Up to 7 inches of rain could fall on the coastal slopes of the San Bernardino Mountains on Saturday and Sunday.

  • Drought easing will continue. Most of California is at or close to normal or even above normal rainfall and snowfall for this date. The additional storms the next 3-4 days will likely create totals in many areas that will be 125% - 150% of normal, or more. Good news for water concerns!

Friday afternoon graphic from the National Weather Service, showing which areas are covered in watches and warnings. The brown color indicates Wind Advisories, the dark green indicates Flash Flood Watches, the pink indicates Winter Storm Warnings, and the mustard indicates High Wind Warnings.

Friday afternoon graphic from the National Weather Service, showing which areas are covered in watches and warnings. The brown color indicates Wind Advisories, the dark green indicates Flash Flood Watches, the pink indicates Winter Storm Warnings, and the mustard indicates High Wind Warnings.

Enjoy the next round of wet weather! Winter doesn’t often last for long here in the desert, so now is your chance to enjoy the dampness while it lasts!

HURRICANE ROSA MARCHES NORTHEAST, AND PACIFIC STORM FORMS OFF CALIFORNIA...

Sunday afternoon is proving to be cloudy and cooler, as forecasts were calling for. Scattered storms have begun popping up in a few areas, and a large shield of rain is lurking south of the Mexican border.

Temps have mostly stayed UNDER 100 degrees today, and in some areas, temperatures are already dropping down under 90 degrees.

The leading edge of the cloud shield associated with weakening Hurricane Rosa has now spread over most of Southern California. Cumulus clouds have been popping up in the increasingly unstable and humid airmass as well, and winds have backed to the southeast and east.

SUNDAY AFTERNOON UPDATES

As of 430pm, strong thunderstorms had formed along the Colorado River Valley from near Yuma up to the Blythe area. Some areas near Blythe have received well over 0.50 inch of rain thus far, and several downdrafts associated with these storms have created dust storms that are currently moving west through the Imperial Valley, as well as west along I-10 near Desert Center.

As of 430p, a few thunderstorms formed from near La Quinta and were moving northeast into the Indio area. Also, a larger area of thunderstorms has been forming and re-forming in an area east of the Salton Sea, towards Blythe. Outflows associated with the thunderstorms have created a dust storm, as indicated by the red dotted line above, moving west.

As of 430p, a few thunderstorms formed from near La Quinta and were moving northeast into the Indio area. Also, a larger area of thunderstorms has been forming and re-forming in an area east of the Salton Sea, towards Blythe. Outflows associated with the thunderstorms have created a dust storm, as indicated by the red dotted line above, moving west.

POSSIBLE DUST TONIGHT?

If the outflows continue marching west, it is possible the skies will become hazy or dusty in the Coachella Valley, sometime in the 530 - 630pm time frame. East winds may increase to the 20-30 mph range for a brief period, if this outflow holds together. Currently, visibility has dropped to less than 0.50 mile in portions of the Imperial Valley near Imperial. Yuma and Blythe had reduced visibility earlier today as well. The next areas to possibly receive dust could be the Salton Sea, as well as the Thermal and Coachella area. More likely than not, this outflow will likely weaken before reaching Palm Springs.

RAINFALL CHANCES TO INCREASE

As previously mentioned, as of 430pm, there is a stationary area of thunderstorms in a line from just south of La Quinta, and to the northeast into Indio. The area of storms continues to reform in the same location, and may begin street flooding soon, if the storms don’t begin moving along. They are forming along the leading edge of the cloud shield of the distant hurricane.

After sunset, most of the thunderstorms are expected to begin diminishing, leaving a chance of light to moderate showers at times tonight. Rainfall is likely to be under 0.10 inch.

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Monday and Monday night is expected to experience more steady rainfall, likely 0.25 - 0.75 inches throughout most of the Coachella Valley. It is possible there may be localized greater amounts, but flooding rains are now expected to be focused more to our east, in Western Arizona. Still, this could bring us a nice soaking.

Several additional storms will move in off the Pacific on Tuesday - Thursday. These storms will mostly focus rain and thunderstorms from the mountains to the coast, with the deserts not likely to receive large precipitation amounts. However, a few showers could make it over the crests and across our deserts.

Enjoy the upcoming cooler weather, as temps will likely drop into the 80s much of the week… with low down into the 60s soon!

STORMY WEATHER POSSIBLE - MAJOR CHANGE ON ITS WAY!

After a relatively stagnant hot pattern throughout much of September, we are going to experience a major weather shift the next 5-7 days.

The computer models are ALL over the place and are having a very difficult time with the precise details, so I would suggest everyone focuses on the overall pattern changes ahead. The specific timing is going to be difficult to predict, but the screaming message is we have the potential for a variety of weather between Sunday and Wednesday, including:

  • Rain

  • Heavy Thunderstorms

  • Flash Flooding

  • High Winds

  • Blowing Dust

  • Much Cooler Temps

WHAT IS RESPONSIBLE FOR THIS IMPENDING STORMY WEATHER?

A complex weather pattern is setting up. Several factors are coming together that are typically very difficult to forecast with precision.

First, a cold low pressure system, one of the first of the fall season, is expected to strengthen off the coast of California, and move slowly to the southeast toward our area. This system will contain some dynamics and unstable air.

Second, powerful hurricane Rosa is located southwest of Baja California. This system is expected to start moving north toward northern Baja over the weekend.

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As the colder low pressure system moves closer to California, the circulation around this system will absorb hurricane Rosa into its wind patterns, allowing the hurricane to be directed toward northern Baja. The incredibly moist tropical airmass will move north into Southern California, Southern Nevada, and much of Arizona starting Sunday afternoon and continuing into Monday. This will likely bring higher humidity (sorry, but not for long!) and some gusty southeast winds and haze to the Coachella Valley.

The hurricane will lose much of its strength as it approaches Baja south of Ensenada. However, it may still produce winds of 45 mph and be a significant Tropical Storm. It’s relatively rare for a landfalling tropical system this close to our area.

The second phase of the storm is expected on Tuesday, possibly a little longer. The low pressure system off the coast will move over our area, bringing scattered showers and thunderstorms. Rainfall amounts will likely be highly variable, with the potential for locally heavy rains in some areas, and dry weather in others.

I would caution anyone from getting hung up on the exact details at this point, since a lot of uncertainty still exists. However, there is a good chance that some areas of the deserts and nearby mountains could see 0.5 - 1 inch of rain, with scattered amounts of 1 - 3 inches or more. It is possible the heavy thunderstorms could dump even more than that in localized areas, if they occur. Some areas may see much less rain. It’s possible some areas will see nothing.

However, it is important that people remain cautious between late Sunday and Tuesday, for the possibility of flash flooding, localized heavy rain and storms. It appears the heaviest rain is likely over Arizona, so anyone traveling to the east Sunday - Tuesday should be alert for any weather warnings or flash flood warnings.

This weather setup has the potential to cause significant problems. Any recent burn areas, like those near Idyllwild, or in the burn areas Orange County, should be alert to the potential for flash floods and mudslides if heavy rain develops.

COOLER TEMPS!!!

This system is expected to finally break our hot weather pattern, with high temperatures falling into the 80s and 90s next week. Overnight lows are likely to drop Ito the 60s several days as well. I can’t speak for anyone else, but I am done with the nagging heat this season. Bring on the cooler weather! If you see someone doing cartwheels next week, it could be me. I’m not sure I can contain my excitement for the drop of temperatures!

Once the tropical portion of the system moves east, it will be replaced by a cooler airmass off the Pacific, that appears to stick around for much of next week. Temperatures will gradually climb back into the 90s later next week… but the relief from the 100+ degree days will undoubtedly bring many of us out of hibernation!

Let’s hope we escape any damaging floods, but get some beneficial rains this week! Incidentally, anyone traveling to the high Sierras should be aware they may experience their first significant snowfall of the season as well. Change is near!

ABOUT THAT COOL DOWN.....

The well advertised cool down has been less dramatic than hoped, but the reduction in humidity has helped make things feel a bit more tolerable the past few days. In fact, nighttime temperatures have FINALLY dropped below 80 degrees the last several nights.

Thunderstorms were common last week over nearby mountains... but they have been largely missing the past several days,

Thunderstorms were common last week over nearby mountains... but they have been largely missing the past several days,

Here have are the official high/low temps at Palm Springs Airport the past several days:

  • 8/26: 106/77
  • 8/25: 107/77
  • 8/24: 107/79
  • 8/23: 109/81
  • 8/22: 108/84

Forecasts last week were calling for temps to be about 3-5 degrees lower than where they have ended up, so August is looking to still hold out to be another impressively hot month, nearly record breaking. Tuesday may be the coolest day, before slowly inching upward again the remainder of the week. As of yesterday, the average temp for August 2018, when you average both the high AND low temp, is 96.9 degrees, which is still 4.9 degrees above normal. 

HIGH WINDS POSSIBLE EARLY TONIGHT

Stronger low pressure to our north will allow the onshore flow from the coast to the deserts to continue strong early tonight, with west and northwest gusts to around 50mph possible through the I-10 corridor from Whitewater to the north Palm Desert and Indio area.  Southwest winds up to 35 mph have also been blowing in the Desert Hot Springs area, up through exposed areas through south Yucca Valley and Joshua Tree. A few areas of blowing dust and sand are possible. The wind will likely creep south into a few of the more populated areas of north Palm Springs, north Cathedral City, north Rancho Mirage and north Palm Desert for a few hours this evening... but should begin to calm down later tonight. Gusty winds may occur again during the afternoon and evening hours the remainder of this week, but at lesser speeds than those expected tonight.

Southwest flow of air at the upper levels has returned a drier airmass to our area.

Southwest flow of air at the upper levels has returned a drier airmass to our area.

FAIR WEATHER THIS WEEK

The remainder of the week is expected to be dry with periods of gusty winds. Temps may slowly creep upwards toward Friday, and humidity will remain low, with dew points remaining mostly in the 30's, 40's and 50's. Elevated fire danger due to low humidity and periods of higher winds.

  • Tuesday: 104/76
  • Wednesday: 106/78
  • Thursday: 108/79
  • Friday: 108/80

Temps in the Yucca and Joshua Tree area will be in the low-mid 90's this week, with nighttime temps down into the 60's. 

POSSIBLE COOLING AND WINDY WEATHER THIS WEEKEND?

The forecast for this weekend is a bit more uncertain. Some computer models are calling for a relatively strong trough of low pressure to move into the West on Saturday, bringing a fall-like weather change. Several other computer models aren't predicting such a dramatic change, with only a slight cool down. For now, most forecasts are calling for slightly cooler weather Saturday and Sunday, with high winds possible again along the I-10 corridor. HOWEVER, if the low pressure system does in fact move south and east, it is quite likely that temps may drop to below 105 once again, and could even fall below 100 degrees, depending on how this system comes together. Strong winds may exceed 50mph along the I-10 corridor as well. Areas of the Sierras in Northern California could see nighttime temps fall well below freezing under such a scenario. Stay tuned as the forecast may change and become cooler for next weekend, depending on how things play out.

In the meantime, enjoy the welcomed break from the humidity! 

HUMIDITY RETURNS TUESDAY... THEN, COOLER??

Yes, it may very well be true! A slightly cooler and drier weather pattern may FINALLY be on its way for a week or so, but not before one more round of humidity tracks into our area from the southeast on Tuesday.

The Palm Springs area will be on the extreme western edge of another southeast push of humidity creeping north from Mexico. Southeast winds are expected to bring elevated humidity levels tonight and Tuesday, with dew points rising back up to or over 70 degrees once again. Cloudiness may accompany the wind shift tonight and Tuesday, with even a very slight chance of a shower or thunderstorm tonight and tomorrow. Hazy skies are likely as well, and even a remote chance of a nighttime haboob if any thunderstorm complexes were to form tonight in the deserts near Yuma, Arizona. The Joshua Tree area has a higher chance of a thunderstorm tomorrow, as has been the case with recent monsoon flow events. The higher terrain helps initiate greater instability and cloud formation I'm that area.

The last bout of humidity and storms brought some much needed rain to the nearby mountains and deserts, as well as some incredible cloud formations and lightning shows.

Mammatus cloud formations from several days ago, south of Rancho Mirage.

Mammatus cloud formations from several days ago, south of Rancho Mirage.

Evening thunderstorms created a light show as lightning lit up the skies. The storm was over and south of the Santa Rosa Mountains, creating over 2 inches of rain in remote sections of the nearby deserts.

Evening thunderstorms created a light show as lightning lit up the skies. The storm was over and south of the Santa Rosa Mountains, creating over 2 inches of rain in remote sections of the nearby deserts.

Thunderstorms over the Big Bear area dropped more than 2 inches of rain as well recently.

Thunderstorms over the Big Bear area dropped more than 2 inches of rain as well recently.

HOW HOT HAS AUGUST BEEN?

Normal high/low temps right now are 106/78.  A look at Palm Springs Airport shows that 79% of the daytime highs have been above average so far this month, and 100% of the nighttime low temps have been above average. This come on the heels of the hottest July on record. Here's how each day stacked up:

  • Aug. 19: 114/85
  • Aug. 18: 112/85
  • Aug. 17: 103/85
  • Aug. 16: 102/85
  • Aug. 15: 106/82
  • Aug. 14: 109/81
  • Aug. 13: 110/84
  • Aug. 12: 110/86
  • Aug. 11: 109/85
  • Aug. 10: 108/89
  • Aug. 9: 104/88
  • Aug. 8: 110/88
  • Aug. 7: 111/86
  • Aug. 6: 115/80
  • Aug. 5: 115/81
  • Aug. 4: 116/86
  • Aug. 3: 116/86
  • Aug. 2: 114/90
  • Aug. 1: 113/88

The silver lining, if there is one, is that there has only been 1 night at or above 90 degrees... which is far better than July. 

SLIGHTLY COOLER WEATHER ON THE HORIZON

By Wednesday, we expect the upper level air flow to switch from a southeasterly to a southwesterly direction. This tends to be a much drier pattern for our area. The lower level humidity levels will likely begin to diminish slowly starting Wednesday, and continuing though this weekend and into next week. This means dew points will likely drop once again into the 40's and 50's instead of the 60's and 70's... so evaporative coolers may in fact work again for those who appreciate the energy savings! Gusty northwest winds will become common again in the afternoon and evening hours along the I-10 corridor, occasionally lurching south for a few hours into the northern sections of the Coachella Valley communities over the next 7 days.  Joshua Tree and Yucca will experience periods of gusty southwest winds as well, with a reduction of 5-8 degrees in temperatures over recent values as well.

As we head into next week, it appears a low pressure system may move into the Pacific Northwest. If this were to occur, even cooler temps are likely next week, with high temps potentially falling BELOW normal for the first time in a long time. It's too far out to predict those temps with certainty yet, but it would be a welcome weather pattern change if it occurs! Here's the current outlook:

  • Tuesday: 109/85 (humid, slight chance of t storms)
  • Wednesday: 108/82 (clear)
  • Thursday: 108/80 (clear, breezy)
  • Friday: 106/79 (clear, breezy)
  • Saturday: 105/78 (clear, breezy)
  • Sunday: 104/77 (clear, breezy)
  • Monday: 103/76 (clear, breezy)
  • Tuesday: 101/74 (clear, breezy

I can't speak for everyone, but I am ready for the humidity to depart for a bit. It's likely we will get a few more monsoon patterns the first few weeks of September... but climatologically they become more rare after Sept. 15th! 

Have a great week! Enjoy the shortening days, as we lose several minutes a day of daylight right now as we head into fall.

HIGH HUMIDITY TO CONTINUE

Another surge of extremely humid air from the southeast created sultry conditions today in the Coachella Valley. Dewpoints surged up to between 75 and 80 degrees this morning, which is commensurate with conditions sometimes experienced in Florida. 

At 6:00 am this morning, Palm Springs Airport reported the following observation:

  • Temperature: 86 degrees
  • Humidity: 77%
  • Dewpoint: 78 degrees

Moist southeast flow banking up against our nearby mountains caused the air to rise and condense, forming a layer of grey low clouds and even patchy drizzle in the valley between about 6-9 am. The satellite imagery this morning showed these localized clouds, with the mountains forming a barrier to the clouds, trapping them between the San Jacinto Mountains and the Little San Bernardino Mountains in Joshua Tree National Park.

Screen Shot 2018-08-08 at 5.37.34 PM.png

I've outlined the cloud cover that matches the topography of the nearby mountains surrounding the Coachella Valley (dotted black line).

Also, the large Holy Fire in Orange County can be seen (outlined in red). The smoke this morning was blowing north into the Inland Empire, and up and over the Cajon Pass into the Victorville area. 

For later tonight, all eyes will be to the east and southeast of us. Currently, large thunderstorm complexes are forming along the Mogollon Rim of Arizona, northeast of Phoenix... as well as over Sonora, Mexico. If these storms hold together and move west across the Arizona deserts, there is a renewed chance of outflows and even another haboob pushing into Western Arizona later tonight. 

If these storms continue, they could move into our area later tonight, likely after 11pm and into the early morning hours. It is a relatively remote chance, perhaps 10% or so, but it's worth mentioning that we could be awakened by a thunderstorm or a potential dust storm under such an unpredictable weather pattern.

Screen Shot 2018-08-08 at 6.44.32 PM.png

Late afternoon satellite showed thunderstorms exploding over Arizona and Northwest Mexico. 

As mentioned in earlier posts, we will be vulnerable to any activity to our east for the next 2 days or so. Then, we expect a few days of drier weather over the weekend before another surge of humidity returns next week. 

GULF SURGE FILLS THE COACHELLA VALEY WITH EARLY MORNING HUMIDITY

Many of you may have taken a step outside this morning, only to notice that the humidity was sky high again. So what happened?

We had a classic "GULF SURGE" event this morning, whose humidity originates from decaying thunderstorms and a shallow humid airmass from the Gulf of California. Let me explain below.

Screen Shot 2018-08-07 at 9.30.30 AM.png

Late last night, a huge thunderstorm complex formed south of Arizona. This is a common place for storms to form this time of year, as very humid air clashes with instability formed by the mountains to provide the perfect breeding grounds for thunderstorms. A light easterly flow allows these thunderstorms to drift west off the mountains into the lower deserts of Western Sonora. They encounter hot temperatures and a shallow moist layer of humid air generated from the Gulf of California, and as they move west toward the gulf, they generally begin to lose their strength for a number of reasons, including the flatter topography the further west the storms navigate, which reduces instability. 

As the thunderstorms collapse, strong downdrafts accompany the decay of the storms. The damp air is heavier than the warmer drier air, so density helps accelerate the moist air outward away from the decaying storms. The result is a gust of wind that accelerates far out in front of the original storm system... much like what causes our famous "haboobs." 

Last night, this shallow gust moved northwest from the Gulf, and continued up into the Imperial and Coachella Valleys. It was carrying the hot humid airmass from the northern Gulf of California... which has water temperatures up over 90 degrees this time of year. That extremely humid airmass easily moves along the mostly flat terrain from near the mouth of the Colorado River, all the way up into our area.

Notice the jump in the dew point and humidity at Palm Springs Airport (below) between 4:53 am and 5:53 am....

Screen Shot 2018-08-07 at 9.59.36 AM.png

The humidity increased from 26% to 57% in one hour. For those that track by the more accurate "dew point" temperature, the dew point went from 50 degrees up to 72 degrees in one hour.

I took a look at communities to our south, and discovered the northwest movement of this humid airmass from late last night. It moved north of the US/Mexico border around 1:30-2:00 am, hitting the Thermal area a few hours later around 4:00 am, and finally moving up into the Palm Springs area around 6:00 am. 

The airmass change was accompanied by a brief wind shift to the southeast, and greatly increased humidity levels. The air is also quite hazy from both the lower level humidity, and the smoke that blew into the valley last night from nearby fires. 

Screen Shot 2018-08-07 at 9.42.13 AM.png

This came in a day earlier than was anticipated. The good news is the humidity layer is quite shallow, so as the day heats up, the humidity will evaporate away as the day progresses. Dewpoints will fall back into the 60's and perhaps back down to the 50's later in the afternoon.

However, we will be increasingly influenced by southeast weather patterns and increasing humidity as the week progresses. Hurricane activity off the Baja coast will also add to the uncertainty. Hope you all enjoyed the brief spell of no humidity while it lasted!

THE EXTREME HEAT CONTINUES....

The month of August is opening up with more relentless heat. It is summer, and hot weather is no stranger to the desert. However, this summer has been one for the record books.

Storm clouds from earlier July when 1.11 inch of rain fell in Palm Springs.

Storm clouds from earlier July when 1.11 inch of rain fell in Palm Springs.

To put this heat into perspective, here are a few interesting facts:

  • Average High temp at Palm Springs Airport: 109.8 degrees
  • Average Low Temp at Palm Springs Airport: 85 degrees
  • Average OVERALL temp for July, 2018: 97.4 degrees.

Palm Springs experienced 14 days over 110 degrees in July, with 9 of those days over 115! There were 5 nights where the low temperature was 90 degrees or higher!

The average high/low for Palm Springs in July is about 108/78. Sad to say, but most of us would dream for a comfortable 78 degrees some morning soon! Look at the toasty temps the past 5 days as well!

  • 8/3: 116/88
  • 8/2: 114/90
  • 8/1: 113/88
  • 7/31: 110/92
  • 7/30: 114/89

UPCOMING OUTLOOK IS VERY HOT WITH INCREASING HUMIDITY AGAIN....

For those hoping for some cooler weather, your hopes will be dashed the next few days. A massive high pressure system will be strengthening over our area through Tuesday. This will only tend to increase our heat by a few degrees the next few days. The only good news is that the humidity levels have dropped and dew points have retreated back into the 40s and 50s. This dry airmass should last until Tuesday or so. It's possible the nighttime lows may finally drop below 90 degrees as the lower humidity allows slightly better radiational cooling each night. We're really splitting hairs at this point though!

Sorry for the bad news.....

  • Monday: 117/88
  • Tuesday: 116/88

POTENTIAL HUMIDITY INCREASES AGAIN AFTER WEDNESDAY....

As the high pressure system over the desert Southwest weekend just a tad, and moves to the north by Tuesday night and Wednesday, the upper level winds will switch back to the southeast and east. This will allow the transport of moisture back into our area. This will support daily thunderstorms across Arizona and Northwest Mexico, which will increase the likelihood of gulf surges and thunderstorm outflows to increase humidity once again. It is quite possible we will experience humid and hazy conditions and southeast winds by Wednesday morning, with dew points over 65-70 degrees again. Afternoons may dry slightly, with more humid conditions returning in the late night and morning hours through the end of the week. The intensity of the humidity will be dependent upon exactly where the storms to our southeast set up, which is impossible to predict at this point.

Temperatures will likely cool a few degrees, as humid air is not as conducive for temps much above 115. Therefore, we may see high temps fall back into the 107-112 range for Wednesday, Thursday and Friday. Any organized storms could even drop those temps further - but this isn't highly likely. The best chance of afternoon and nighttime thunderstorms during this time period will be in the nearby mountains, as well as the Joshua Tree/Yucca area. Perhaps we will get lucky and score some rainfall. Too early to tell.

HURRICANES OFF MEXICO NEXT WEEK?

Long range forecasts are predicting a series of hurricanes to potentially develop off Mexico next week. At this time, they aren't expected to hit Southern California, and instead will curve out to sea off Baja. However, the circulation around the backside of these systems could only serve to strengthen the southeasterly wind flow, and potentially solidify the transport of humidity our way.  It will be interesting to see if the computer weather models change their tune, as a shift more north could support dramatically cloudier or wetter weather for Southern California. 

SEA TEMPS ARE TOASTY!

Just to our west, the water temperatures off the coast of San Diego have risen to a record breaking 77-79 degrees last week! This is far above the normal 68-71 degrees more typical for this time of year. Anyone traveling to the coast has likely felt the muggier conditions that are a result of these abnormally high water temps. Take a look at the imagery via this National Weather Service tweet, from a few days ago!

Screen Shot 2018-08-05 at 4.58.49 PM.png

So, the screaming message this week is STAY COOL, and HYDRATE! Let's hope we get some moisture later this week! Enjoy the lack of humidity Monday and Tuesday while it lasts!

ROUGH WEEK IN THE DESERT... MORE DUST LATER TONIGHT?

It has been a rough summer week here in the Palm Springs area. Extreme heat, periods of humidity, and smoke from the nearby Cranston fire have all contributed to a cauldron of atmospheric conditions that have strained even the hardiest summertime resident.

The sun was red several evenings ago as it filtered through the pyrocumulonibus cloud rising from the Cranston Fire. Lightning and thunder was reported underneath the smoke plume.

The sun was red several evenings ago as it filtered through the pyrocumulonibus cloud rising from the Cranston Fire. Lightning and thunder was reported underneath the smoke plume.

Currently, the Cranston Fire appears to be advancing very slowly to the southeast of Idyllwild, currently moving away from the town. The northwest areas of Garner Valley have been most vulnerable the past 36 hours. Most other areas are burning much less ferocious than in days past. 

INCREDIBLE HEAT LAST WEEK

Temperatures were remarkably hot this past week. Palm Springs International Airport (PSP) had a long run of temps over 110. Often, heatwaves of this magnitude will last only a few days... but this one lasted nearly an entire week. 

July 27: 115/86

July 26: 114/89

July 25: 116/91

July 24: 121/90

July 23: 119/87

July 22: 115/83

 

BRIEF RETURN TO SOUTHEAST FLOW TONIGHT & SUNDAY - 

An uptick in southeast monsoon flow is expected tonight and Sunday. This will bring about another surge in moisture tonight and tomorrow. Also, thunderstorms are blossoming over sections of Arizona, and could possibly produce a haboob as they track west from Phoenix and Tucson later this afternoon and this evening.

There is a slight chance these storms will hold together as they progress west, and if they do so, there is the possibility of another dust storm across the Coachella Valley tonight. Currently, the large thunderstorm complex is growing to the southeast of Yuma, Arizona. It is moving northwest. A large outflow boundary is possible as the system moves toward the lower Colorado River Valley. If this occurs, a large haboob could form. Another area of storms is forming in the high country to the northeast of Phoenix, and will likely move into the Phoenix area after 6pm. These storms could congeal as they move to the southwest as well... and could be a secondary source of high winds for eastern California tonight after 8-9pm.

Either way, even if a haboob fails to materialize tonight, it is possible the entire Coachella Valley will experience additional fresh winds from the east and southeast at some point this evening between 8pm and midnight or so... along with haze and higher humidity. Dewpoints will likely surge up to or above 70 degrees once again. Another sticky morning is in store for us tomorrow!

SUNDAY MOUNTAIN STORMS

Sunday will bring a much better chance of afternoon thunderstorms across the local mountains. Firefighters will clearly be monitoring weather conditions in case erratic outflow winds affect the Idyllwild area. Additionally, any outflows from strong Arizona storms tonight could bring a wind shift to the southeast in the mountains later tonight - this will need to be carefully monitored in the Idyllwild area, as winds have been mostly from the west the past several days up there. Erratic winds would not be a positive development. Humidity will likely be higher on Sunday though, which is great news. It is possible a few thunderstorms could occur across our desert areas as well, but the chance is very slight.

NEXT WEEK COULD TURN DRIER

Longer term forecasts are trending drier next week. At this point, a diminishing chance of afternoon and evening thunderstorms will likely support only very isolated storms at best. The monsoon moisture from the southeast is likely to remain east of the Colorado River most of next week, if models are correct. This is tantalizing close to our area though, so any change in the weather pattern, even by 150 miles, could keep afternoon thunderstorms in the forecast. 7-10 day computer models suggest a trough of low pressure moving off the California coast the following week of August 6th, and could open the door for disturbances from the south. Any hurricane formation off the Mexico coast could spread moisture into the Desert Southwest under such a pattern. Temperatures will also likely remain at average under such a weather regime. Let's see if the future models hold to this or not!

In the meantime, there are some amazing heroes among us. The brave firefighters that helped protect Idyllwild have been in town (Many located at the V Hotel). Idyllwild will need our help once the town is ready to accept visitors and the electricity returns. Our cherished local mountain getaway and the local businesses that rely on tourism will need us! Let's hope the fire continues to be brought under control and this horrific week will be behind us soon. Stay hydrated out there folks!

 

MORE DUST LATER TONIGHT?

A wall of dust moved through the Coachella Valley early this morning before 2:30 and 3:30 am, reducing visibility to below 2 miles for several hours, before a very gradual improvement this afternoon. 

The haboob was caused by several large thunderstorm complexes that formed in Arizona late last night, and moved west toward California. Most of the storms began weakening after moving across the Colorado River, but the high winds of 30-45 mph were enough to propel the dust storm northwest from Yuma and across the Imperial Valley, the Salton Sea, and finally, into the Coachella Valley. Here's a graphic displaying the progress late last night and early this morning.

Screen Shot 2018-07-09 at 6.39.02 PM.png

An even stronger batch of thunderstorms is moving west through Central Arizona tonight. It is unclear if they will hold together long enough for a repeat dust storm tonight, but current observations suggest we have a decent chance of a repeat performance.

As of 645p, widespread dust storms are marching westward, west of Phoenix and Casa Grande, along I-10 and I-8. Winds tonight have been gusting 60-70 mph as storms moved through the Phoenix area. This is much stronger than last night's gusts, which started in the 50 mph range. Travel along I-10 and I-8 into Arizona will be dangerous this evening and should be postponed if possible, until conditions improve. Here's a current radar image.

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This is a very impressive line of storms. 

It's always difficult to predict thunderstorm development, but it is quite possible they could hold together enough to drift through our area tonight. Movement would suggest the potential of an earlier arrival than last night, most likely after 10-11 pm and into the early morning hours. More humidity, haze and high winds are possible, as well as reduced visibilities once again.

Even if we are lucky enough to be spared another haboob tonight, Tuesday and Wednesday will see a renewed chance of thunderstorms, high winds, more dust storms and possible flash floods. This will keep temps down from their extreme levels felt a few days ago. Things appear to be trending drier Friday through the weekend, but that is of medium, not high probability.

Take those outdoor umbrellas down the next few days in case we get more strong weather, and watch/listen to the National Weather Service for any severe weather warnings, if they are issued.