The marine layer will remain near 5000 feet deep with patchy drizzle and light rain at times from tonight into Thursday morning. The marine layer will then 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, with gusts 40 to 50 mph and isolated gusts to 65 mph through the passes. High temperatures today will be as much as 20 to 25 degrees below average for the mountains. High temperatures on Thursday will warm a few degrees. 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, into the 90s for the Inland Empire and to near 110 for the lower deserts.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
This afternoon, The marine layer remains about 5000 ft deep with low clouds covering most of the area west of the mtns. The light precip west of the mtns from last night/this morning has ended. Inland temperatures are mostly a few degrees lower than at this time yesterday and as much as 10-15 degrees cooler in the mtns.
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 today will be as much as 20 to 25 degrees below average for the mountains with high temperatures mostly in the 60s for the coast, valleys, and high desert, in the 40s and 50s for the mountains, and in the upper 70s to mid 80s for the lower deserts. 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.
271800z, Coast/Valleys/Foothills, SCT-BKN cumulus clouds based 4-6 kft MSL are covering most of the coastal basin, scattering out intermittently over coastal areas. Clouds are expected to scatter out further early this afternoon, leaving patchy cigs limited to the foothills and FG (vis 0-3 SM) to the lower mountain areas. Cloud coverage will expand slightly into lower elevations after 01z this evening, though total coverage is expected to remain patchy all night. After 02z, the main bases will generally be 3-5 kft MSL with periodic MVFR cigs and spotty DZ/-RA through Thursday morning. Higher Mountains/Deserts, Mostly clear skies and VFR conditions expected through the TAF period. West winds pick up once again this afternoon gusts of 25-40 kts, locally up to 50 kts through passes. Winds gradually taper off between 04-10z Thursday, but remain elevated through passes overnight.
Elevated winds (gusting to 20 knots) and seas (6-8 feet) continue through early this afternoon, particularly near San Clemente Island. These conditions may generate hazardous conditions for small craft, and a Small Craft Advisory remains in effect until 1 PM this afternoon. Winds and seas decrease through this evening, with no hazardous marine conditions expected thereafter 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, Small Craft Advisory until 1 PM PDT this afternoon for Waters from San Mateo Point to the Mexican Border Extending 10 to 60 nm out including San Clemente Island.
