textproduct: San Diego

SYNOPSIS

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.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

Updated Aviation discussion coincident with the 06z TAF package.

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.

AVIATION

280600Z...Coast/Valleys/Coastal Mountain Slopes...VFR conditions prevail this evening, with FEW-SCT clouds around 3500-5000ft MSL, with more BKN-OVC clouds at 5000-7000ft MSL along and adjacent to the coastal mountain slopes. Very sparse DZ/-RA is possible overnight (<10% chance) until around 14z Thurs. Should any instances of this occur near terminals, brief CIGs near 2500-3500ft may accompany them. Mostly clear skies expected through the day on Thursday, with perhaps FEW Cu ~5000ft MSL. A very similar set up of cloud cover returns by 03z Fri, with clouds near 5000ft up against the higher terrain, with FEW-SCT clouds ~3500ft for the coasts/valleys. DZ/-RA is possible again between 06-18z Fri, though chances will be a little higher than tonight, closer to 20-30%.

Higher Mountains/Deserts...Mostly clear skies and VFR conditions expected through the TAF period. Gusty westerly (onshore) winds currently gusting 25-35 kts gradually wind down through 12z overnight, but remain elevated through the passes into Thursday morning. Widespread gusts pick back up after 18z Thurs, with gusts closer to 20-30 kts.

MARINE

No hazardous marine conditions expected through Sunday.

SGX WATCHES/WARNINGS/ADVISORIES

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.