FIRST SIGNIFICANT STORM OF THE SEASON FOR SO CAL!

STORM.

Definition, in case anyone has forgotten:

"noun. A violent disturbance of the atmosphere with strong winds, and usually rain, thunder, lightning or snow."

After the driest start ever on record for many portions of Southern California, a powerful winter storm will finally change our sensible weather of late, with the opportunity for damaging winds, a small/moderate amount of rainfall and much cooler temperatures for a few days.

After a long hiatus, and nearly perfect weather the past few months, I've had little reason to post. This ridiculously extended period of benign weather will at least see a temporary reprieve. Palm Springs area residents should expect a rapid deterioration of sunny and warm weather conditions and a low-moderate potential for a high wind event. Wet droplets may fall from the sky again as well.

POTENTIAL IMPACTS

WIND: Moderate to High Impact Possible. There is a low-moderate probability of damaging gusts as high as 50-75 mph in some areas Monday evening through Tuesday night. There is the possibility of some strong southerly gusts surfacing along the southern foothills Monday night, especially in the Andreas Hills, Araby, Cathedral City Cove, 111 corridor in Rancho Mirage, and South Palm Desert. The cold front should pass through Tuesday morning, with WNW gusts coming down along the 10 corridor from Whitewater to Indio by Tuesday afternoon. There is a low possibility of a downsloping event in more widespread areas of Central and South Palm Springs if the jet stream aligns from the WSW direction on Tuesday morning and afternoon. This is NOT a sure bet, but the potential exists. If downsloping were to occur, gusts over 50-75 mph could hit portions of Palm Springs normally sheltered by high winds. Therefore, Monday would be a GREAT TIME to tie up open pool umbrellas and other loose backyard furniture, just in case! Large areas of the high deserts and Joshua Tree will likely experience strong winds from Monday afternoon through Tuesday night as well!

RAINFALL: Low to Moderate Impact. Rainfall amounts currently are expected to range from just a few sprinkles in some areas, to as much as 1 inch on the higher peaks of Joshua Tree National Park, and near the mountains. Most areas, however, will likely see only 0.10-0.50 of an inch - which will be enough to give a nice soaking, sans major flooding concerns. Isolated thunderstorms are possible Tuesday morning and could bring isolated higher rainfall amounts and localized flooding of roadways and washes if this were to occur. The potential for heavy rainfall is currently low to moderate.

TEMPERATURES: High temperatures will drop for several days, but will recover back to near 80 degrees by the upcoming weekend, for those that enjoy sunny warm winter weather.

Monday: 70/52

Tuesday: 62/47

Wednesday: 73/50

Thursday: 77/51

Friday: 78/52

Saturday: 80/52

Sunday: 81/52
 

ANALYSIS

As of Sunday night, the latest satellite pictures show two areas of low pressure off the West Coast.

source: SFSU (GOES West image)

source: SFSU (GOES West image)

The upcoming storm system consists of two components currently. Area #1 is a subtropical area of low pressure that has been lingering far to the west of the southern tip of Baja for several days. This system is weakening, and will bring mild and mostly cloudy conditions for most of tonight and Monday, with a few sprinkles possible.

Area #2 is the stronger portion of the system, which is currently strengthening and moving to the southeast. It will absorb weaker system #1 and will create a strong cold front that will move through Palm Springs sometime on Tuesday morning. A strong jet stream digging in around this system creates the potential for high winds in many areas of Southern California.

Current computer models show strong jet stream winds circulating right into Southern California on Tuesday (below), centered around the low pressure that is expected to crash ashore north of Santa Barbara.

source: SFSU

source: SFSU

SIGNIFICANT RAIN AND SNOW FOR MOST OF THE WEST

Computer model projections show impressive rainfall (or rainfall equivalent for higher elevations where snow will fall). Large areas of the mountains of California are expected to receive 4-6 inches of rain, which may translate to 3-4 feet of snow at the highest elevations.

source: NOAA/NWS/NCEP/WPC

source: NOAA/NWS/NCEP/WPC

Our local mountains will likely receive some white by Tuesday, as snow levels come down from 8,000 feet to near 5,500 feet. Expect 2-7 inches in Idyllwild on Tuesday, with more than a foot possible on the higher peaks near Big Bear. Areas west of the mountains such as the Inland Empire, San Diego, Orange County and Los Angeles could see 1-3 inches of rain, and lower mountain slopes could receive over 5 inches. Mudslides and debris flows could be a major problem for recent fire zones such as near Santa Barbara/Ventura, the San Fernando Valley and in Northern California.

LONG RANGE HOPE FOR MORE STORMS?

Currently, long term forecasts show another strong high pressure building back off the Pacific to the west of California after the next storm, with warm dry weather lasting about another week. The soonest another system could possibly tease California would likely be the middle of next week, but it's too soon to know if this will occur. Longer range forecasts show additional opportunities for systems later in January. One can hope!

Enjoy the wild skies and windy days we will be treated to the next few days!