High temperatures for today will remain as much as 5 to 10 degrees below average for the inland valleys thanks to the marine layer stretching well inland. A slight warming and drying trend into this weekend takes temperatures back to near normal for Saturday and Sunday as the marine layer becomes gradually shallower. After a briefly cooler day on Monday, another warming trend will begin next Tuesday with high temperatures returning above average by Wednesday.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
Today through this weekend,
Current satellite and 500mb RAP analysis this afternoon reveals a potent upper low centered across northern California this afternoon. This feature is inducing low thickness and southwesterly flow aloft, which is fueling the below average temperatures seen the last few days. Highs this afternoon are running around 10 degrees below normal for the inland areas. A very deep marine layer has also resulted from the influence of the nearby upper low, which spread well through the coastal mountain slopes, with even isolated instances of drizzle along the coast this morning. As we progress into this weekend, this upper low will gradually kick east towards the northern Rockies, allowing a weak upper ridge to pass through. This will bring a subtle warming trend to the region, bringing temperatures back to near normal for Saturday/Sunday. This passing ridge will also serve to squish down the marine layer some, restricting cloud cover towards the coasts and western valleys.
Monday through midweek,
Following the subtle weekend warmup, another weak trough is set to swing through Monday/Tuesday. This will knock temperature back down a few degrees, back to cooler than seasonal norms, for Monday and Tuesday. Beyond Tuesday, models begin to divergence in the resolution of the upper ridge across the south-central United States. Some ensemble clusters favor a stronger ridge that can push further west, with other clusters keeping the ridge weaker and further east. This is leading to a fairly large spread in temperatures come mid next week, thought the NBM mean is favoring a warming trend that brings temperatures around 5 degrees normal for Wednesday.
180400z, Coast/Valleys, Low clouds based around 2000-3000 feet MSL will become widespread along the coast 06-08Z, filling in the entire coastal basin by 12Z Fri. Decreased confidence in timing of cig development for KSNA/KONT/KSBD. Clouds will scatter 16-18Z Fri. Low clouds are expected to return to coastal TAF sites after 06Z Sat.
Mountains/Deserts, Mostly clear and VFR conditions through Fri.
No hazardous marine conditions are expected through Tuesday.
Ca, None. PZ, None.
