High temperatures will gradually rise through Friday and Saturday to as much as 10 to 15 degrees above average for the inland valleys. Weak onshore flow will spread low clouds and cooling into the coast and valleys for Sunday and Monday with not much change for the deserts.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
This afternoon, Temperatures are generally warmer than at this time yesterday especially in the mountains and deserts, although the coastal areas are near or a little cooler. Surface pressure gradients are offshore but only enough to support east winds gusting to around 25 mph in the wind-prone locations of the mtns. A weak upper level disturbance embedded in the flow to our southwest will bring increasing mid and high clouds over SoCal tonight through Wednesday. This could prevent low temps from dropping as low as this morning.
From previous discussion, An amplified ridge of high pressure over the west coast will weaken a little and shift eastward briefly on Wednesday as a shortwave trough moves inland to our north. This may slow the general upward trend in temperatures but that trend will continue into Saturday under mostly clear skies as the ridge rebuilds. Friday and Saturday will likely be the warmest days with high temperatures reaching the low 80s in portions of the inland valleys. These temps are 10-15 degrees above average. Temps elsewhere will mostly be in the lower to mid 70s near the coast, with the lower deserts in the low 80s. Nights will continue to be cool through the end of the week but the lack of moisture will likely limit
For Sunday and Monday, The dominant ridge is weakened significantly and displaced eastward on Sunday and Monday as a more vigorous shortwave trough moves in from the Pacific. This will bring a return of onshore flow, with marine layer low clouds/fog and lower temperatures spreading inland. Forecast details are uncertain but Monday looks like it will be the coolest day with daytime high temps near to about 7 degrees above seasonal averages.
Temperatures begin to rebound next Tuesday as the upper level ridge begins to rebuild and the marine layer is once again restricted to the immediate coast..
272130z, VFR conditions with increasing high clouds AOA 20000 feet MSL through Wednesday morning.
No hazardous marine conditions are expected through Sunday.
Ca, None. PZ, None.
