textproduct: San Diego

SYNOPSIS

Showers with a slight chance of thunderstorms will move southeastward across the area today through this evening. Drying will develop over the weekend and continue into early next week with periods of weak to moderate strength gusty Santa Ana winds for Sunday through Tuesday. A low pressure system from the southwest could bring a return of precipitation some time during the middle to latter part of next week.

SHORT TERM (Today through Sunday)

Showers will move southeastward across the area for this morning into this evening along with a slight chance of thunderstorms. Additional rainfall through tonight for Orange and southwestern San Bernardino Counties is expected to range from 0.50 to 0.75 inch near the coast to 1.5 to 2.5 inches in the San Bernardino County mountains, locally exceeding 3 inches on the coastal slopes of the eastern San Gabriel Mountains. Amounts will decrease from north to south with around 0.25 inch expected over far southern San Diego County. Island-band showers may continue near the coast, especially in San Diego County, overnight into early Saturday.

Otherwise, drying will develop over the weekend and continue into early next week with offshore flow developing on Sunday. High temperatures will continue to cool on Saturday, then begin to warm for the coast and valleys on Sunday by around 5 degrees. High temperatures on Sunday will be mostly in the 60s for the coast, valleys, and lower deserts.

LONG TERM (Monday through Thursday)

Dry weather with offshore flow will continue for Monday and Tuesday with weak to moderate strength Santa Ana winds. High temperatures will continue to warm for Monday and Tuesday with high temperatures for the coast and valleys a few to around 5 degrees above average on Tuesday and within a few degrees of average for the mountains and deserts. High temperatures on Tuesday for the coast, valleys, and lower deserts will be mostly in the mid 60s to lower 70s.

For mext Monday, the models are in reasonably good agreement in having a cutoff low well to the southwest of the area, centered around 20N/130W, with another low pressure system moving eastward across the Gulf of Alaska. The general evolution beyond that for the middle and latter part of next week is for the Gulf of Alaska low pressure system to move southeastward toward the California coast while the cutoff low weakens and moves toward the northeast while drawing subtropical moisture northeastward into far southern California.

While precipitation chances are increasing for southwestern California for the latter half of next week, there is lower confidence on when and how much precipitation might fall. Currently, chances for measurable rainfall as well as chances for relatively heavier precipitation are highest on Thursday (New Year's Day) and Friday. For early Wednesday morning through early Saturday morning for the coast to the mountains, NBM chances to receive one inch or more of rainfall some time during that period are generally 45 to 65 percent.

AVIATION

260945Z....Coasts/Valleys...Very patchy low clouds are beginning to develop, generally below 1000ft MSL bases with more widespread mid level clouds around 5000-7000ft MSL. Low clouds will increase in coverage for both Orange and San Diego counties generally after 12z with bases ranging from 700-1500ft MSL and locally higher around 2500ft MSL. Bases should rise to above VFR after 18z but incoming RA today may briefly bring conditions down to MVFR/IFR. Gusty southerly winds up to 20kt are possible as this next surge of moisture moves through the area. Moderate up/downdrafts downwind of the Santa Anas into the Inland Empire through through early afternoon. Rain chances decrease after 05z for everywhere other than San Diego County.

Mountains/Deserts...Low clouds around 7000 ft MSL are expected to slowly lower to around 1000-3000 ft MSL after 12z. Winds will fall off today before increasing westerly winds for the desert slopes of the mountains after 06z Sat. Surface gusts up to 35-45 knots at times, locally higher through mountain passes, with mod up/downdrafts near the mountains.

Region-wide...A band of moderate to locally heavy rain moves into the region from the northwest starting around 14z, and will move across the area through the daytime, reaching San Diego County likely around 23z-03z. A few hours of MVFR to locally IFR CIGS/VIS are expected as the rain moves through. SCT -SHRA in the wake of the main band will create intermittent CIG/VIS reductions through tonight.

MARINE

South to southwest winds strengthen again today with gusts near 20 knots at times. Winds will then turn northwest and gradually decrease late tonight into Saturday. Otherwise, no hazardous marine weather.

BEACHES

Westerly swell (250-270 degrees) will lead to surf building 5 to 8 feet through Saturday. Highest surf is expected for west-facing beaches. A High Surf Advisory is in effect now through Saturday afternoon.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...High Surf Advisory until 11 AM PST Saturday for Orange County Coastal Areas-San Diego County Coastal Areas.

Flood Watch through this afternoon for Apple and Lucerne Valleys- San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire.

PZ...None.