Patchy drizzle and light rain at times tonight into Thursday morning and again Thursday night. The marine layer will steadily decrease in depth into next week, with night and morning coastal low clouds only spreading into the western valleys at times. Southwest to west winds will continue through tonight in the mountains and deserts. Minor warming Thursday, then the warming trend will continue through the middle of next week with high temperatures for next Wednesday around 8 to 12 degrees above average for inland areas.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Evening update, Isolated light showers are moving into Orange County this evening, but hi-res guidance shows this will taper off over the next couple hours. Otherwise patchy drizzle is possible tonight as a very deep marine layer, upwards of 6000 ft, remains in place. The 00Z sounding shows no saturation in this layer, however, and the cloud deck itself is somewhat thin, so even drizzle may be a stretch. Better chances of light showers tomorrow evening as the main trough axis with the upper level low moves through. Otherwise breezy southwest to west winds will persist in the deserts this evening, weakening overnight.
Previous discussion, The low pressure system with a closed upper low over central CA will continue to bring the following conditions: A marine layer which will remain near 5000 feet deep into Thursday, with patchy drizzle or light rain at times tonight into Thursday morning. The marine layer will then steadily decrease in depth into next week. Southwest to west winds will continue in the mountains and deserts through tonight, with gusts to 40 to 50 mph and isolated gusts to 65 mph through the passes.
High temperatures will rise a few degrees on Thursday and another 8 to 12 degrees for inland areas on Friday as the low pressure system moves inland. High temperatures on Friday will still be around 10 degrees below average for the valleys and deserts and 10 to 15 degrees below average for the mountains. High temperatures on Friday will range from the mid to upper 60s near the coast to the lower to mid 70s for the Inland Empire with the lower deserts in the mid to upper 80s.
Numerical models are in good agreement through Saturday with respect to the synoptic pattern before diverging as we move into next week. Forecast details are somewhat uncertain but we can reasonably say that the warming trend will continue through the middle of next week with high temperatures for inland areas around 8 to 12 degrees above average for next Wed. The marine layer will become shallower into next week with night and morning coastal low clouds only spreading into portions of the western valleys late each night.
272350z, Coast/Valleys/Foothills, Patchy low clouds with bases 3500-5500 ft MSL are spread through the coastal basin. Cigs will intermittently SCT-BKN through 16-18Z with the exception of the coastal slopes and foothills where low clouds will cling. Low clouds will increase in coverage once again after 00Z Friday beginning in the valleys. Chances for patchy DZ/-RA again late this evening into tomorrow morning from 03-14Z. Higher Mountains/Deserts, Mostly clear skies and VFR conditions expected through the TAF period. West winds with gusts of 25-40 kts, locally up to 50 kts through passes continue. Winds will gradually ease between 04-10z, but will remain elevated through passes overnight. West winds will slowly increase after 18Z but with gusts 15-25 kts, locally up to 30 kts in the deserts and desert mountain passes.
Winds and seas will continue to decrease through this evening, with no hazardous marine conditions expected through Sunday.
Ca, Wind Advisory until 5 AM PDT Thursday for Riverside County Mountains-San Diego County Deserts-San Diego County Mountains-San Gorgonio Pass near Banning.
PZ, None.
