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!!!