textproduct: San Diego

SYNOPSIS

A low pressure system from the northwest moving into the western states will bring stronger onshore flow and a cooling trend through the weekend with Sunday high temperatures near the coolest for the date for a few locations. Southwest to west winds for the mountains and deserts during the afternoon and evening will strengthen through Saturday, then weaken for early next week. The marine layer will deepen into the weekend with night and morning coastal low clouds extending well inland and onto the coastal slopes of the mountains by early Sunday with some patchy late night and early morning drizzle for the coast and valleys over the weekend. Then gradually warmer next week with high temperatures returning to near average some time late next week.

SHORT TERM (Today through Saturday)

A low pressure system from the northwest moving into the western states will bring stronger onshore flow across southern California through the weekend with the strongest onshore flow on Saturday. This will spread cooling inland through the weekend. High temperatures for today for the coast, valleys, and mountains will be a few to around 5 degrees below average with the lower deserts a few to around 5 degrees above average. High temperatures for today will range from around 70 near the coast to the 80s to around 90 for the Inland Empire with 106 to 112 for the lower deserts.

With the cooling, high temperatures on Saturday will be as much as 10 to 15 degrees below average for the mountains and inland valleys. High temperatures on Saturday will range from around 70 near the coast to the mid 70s to lower 80s for the Inland Empire with the mid 90s to 103 for the lower deserts.

Onshore flow will strengthen through Saturday with southwest to west winds for the mountains and deserts during Saturday afternoon and evening gusting to 30 to 40 mph with gusts to 75 mph in the northern Coachella Valley below the San Gorgonio Pass.

The marine layer will deepen more slowly into Friday, then more rapidly for the weekend with night and morning coastal low clouds extending into the western valleys early today, into portions of the inland valleys for early Friday, inland across much of the valleys for early Saturday, and onto the coastal slopes of the mountains for early Sunday. There could be some patchy drizzle from this deeper marine layer over the weekend.

LONG TERM (Sunday through Wednesday)

The cooling trend will continue into Sunday with high temperatures on Sunday ranging from around 70 near the coast to the 70s for the Inland Empire with the 90s for the lower deserts. High temperatures for some locations on Sunday could be near the coolest on record for the date. A slow warming trend will begin on Monday with high temperatures returning to near average some time late next week.

AVIATION

251730Z...Coast/Valleys...Patchy low clouds to persist along beaches, but coastal airports will be scattered out through the afternoon. Low clouds around 2000 feet MSL will push ashore around 01Z and eventually fill the coastal basin again overnight. Vis reduced inland 1-5SM with partial terrain obscuration 2000-3000 feet MSL. Scatter out Friday 16-18Z.

Mountains/Deserts...Mostly clear and VFR conditions expected through Friday morning, except for coastal slopes shrouded in fog below 3500 feet MSL 10-15Z Friday. West-southwest winds 25-35 kts gusts to 45 kts through mountain passes and locally into deserts after 21Z, decreasing a little early Friday morning. Occasional MOD up/downdrafts in lee of mountains.

MARINE

No hazardous marine conditions are expected through Tuesday.

BEACHES

A long-period south swell will continue to bring surf of 3 to 6 feet today with the highest surf on south facing beaches. See the Beach Hazards Statement for details.

FIRE WEATHER

Lowest daytime humidity for the deserts will fall to around 10 percent for today and Friday during the afternoon and early evening. That low humidity combined with southwest to west winds gusty to 25 to 35 mph during the afternoon and evening will bring near critical fire weather conditions for the deserts onto the desert slopes of the mountains during the afternoon and early evening for today and Friday.

SGX WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement through this evening for Orange County Coastal Areas-San Diego County Coastal Areas.

Extreme Heat Warning until 8 PM PDT this evening for San Diego County Deserts.

PZ...None.