textproduct: San Diego

SYNOPSIS

Cooler and breezy conditions will continue through Thursday with west winds in the mountains and deserts gusting 35 to 50 mph. For Friday and Saturday, offshore surface flow and high pressure aloft will bring warming and drying with northeast winds along and below the coastal slopes of the mountains. Slightly cooler with weaker winds for early next week.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

Evening update... The 00Z sounding shows the boundary layer nearly 6000 ft deep topped by a weak inversion. With the loss of daytime heating, the stratocumulus clouds have dissipated except where they remain banked up against the mountains. Hi-res guidance seems to be struggling with this lack of cloud cover and is spitting out light precipitation overnight. If clouds can redevelop and thicken enough with the approaching upper level low moving into the Pac NW, some spotty drizzle isn't totally out of the question. Otherwise breezy southwest to west winds continue across the mountains and deserts into Thursday with gusts around 35-45 mph, locally as high as 55 mph along the wind prone desert mountain slopes and below the San Gorgonio Pass. Thursday will remain cool with highs a few degrees below normal.

Previous discussion... Friday, winds at the surface shift to offshore as high pressure builds aloft. This will bring higher temperatures to the coasts and valleys with temperatures 5-10 degrees above the seasonal average. Northeast winds will be breezy with the highest winds in the coastal slopes and mountain areas. Gusts of 35-45 mph area expected in desert areas and the San Diego Valley. Stronger wind gusts of 50-65 mph will be possible on coastal mountain slopes and adjacent valleys.

Saturday through Wednesday... Offshore winds continue into Saturday as high pressure continues to fill in over the area. Expect wind gusts of 40 to 50 mph in the coastal slopes of the mountains and deserts, locally 55-60 mph. High temperatures will be in the 70s and mid 80s along the coast and in the valleys, upper 50s to mid 70s in the mountains, and 80s to low 90s in the Coachella Valley and San Diego deserts.

Conditions west of the mountains will cool Sunday as onshore flow returns. Temperatures will continue to increase in the mountains and deserts. Next week, temperatures fluctuate a few degrees into mid- week with mostly clear skies in the afternoon.

AVIATION

020400Z...Coast/Valleys...SCT low clouds based 2000-5000 ft MSL currently over the foothills with patchy coverage through the coastal basin. Coverage of low clouds will continue to increase this evening with most of the coastal basin filling in by early Thursday morning. Bases will hover around 2000-3000 ft MSL overnight. By late Thursday morning, clouds will rise above 3000 ft with most areas scattering out 17-19Z. Areas in San Diego County may remain BKN (40- 50%) through the afternoon. Coverage increases and bases lower below 3000 ft again 02-05Z Fri, but low clouds should remain mostly confined to San Diego County as flow begins to turn offshore.

Mountains/deserts...Coastal slopes below 5000 ft shrouded in FG, occasionally reaching higher elevations through 18Z Thu. Otherwise, VFR conditions through Thursday evening. Strong westerly winds will continue through Thursday afternoon with gusts 35-50 kts along coastal slopes and through the High Desert. Gusts reaching 25-40 kts along the floor of the lower desert. Areas of BLDU expected with vis 3-5SM, especially in the High Desert. Winds slowly weaken 00-06Z Fri before turning northerly and strengthening along coastal slopes Thursday night.

MARINE

Areas of northwest wind gusts to exceed 20 knots late Thursday in the outer waters. Otherwise, no hazardous marine conditions expected through Monday.

SKYWARN

Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions.

SGX WATCHES/WARNINGS/ADVISORIES

CA...Wind Advisory until 11 PM PDT Thursday for Apple and Lucerne Valleys-Coachella Valley-Riverside County Mountains-San Bernardino County Mountains-San Diego County Deserts-San Diego County Mountains-San Gorgonio Pass near Banning.

PZ...None.