textproduct: San Diego

SYNOPSIS

Windy over the mountains and into the deserts, well below average temperatures across Southern California, and a deeper marine layer can be expected this weekend. Areas of drizzle are possible, with Saturday morning as the most likely day. Conditions will gradually warm into next week.

Updated Aviation Discussion for the 00z TAF Package

A unseasonable trough of low pressure is expected to dig into the Great Basin this weekend. This will increase the onshore pressure gradient, resulting in stronger westerly winds on the desert mountain slopes into the deserts, well below average temperatures, and a deeper marine layer. By Sunday, highs are expected to be 7 to 9 degrees below average at the coast and low deserts and 15 to 20 degrees below average in the valleys, mountains, and High Desert. There is also a potential for patchy drizzle west of the mountains, most likely on Saturday morning.

Winds will begin to increase today on the desert mountain slopes and in the deserts and strengthen into Saturday. Wind gusts Friday will be 35 to 50 mph, combined with relative humidity 7 to 15 percent in the deserts will create periods of near critical to locally critical fire weather conditions in the deserts. For more information on fire weather concerns, see the Fire Weather section below. Winds are expected to peak in strength on Saturday afternoon and evening, with peak gusts 50 to 65 mph with locally higher gusts possible below the San Gorgonio Pass. Winds will decrease Sunday into next week.

Global ensembles are indicating broad scale weaker troughing may linger into the end of next week. Even with the lingering troughing, heights will rise leading to a gradual warming. About 27 percent of ensemble guidance is indicating a ridge may begin to build back in by next weekend. By next Thursday, highs will be 3 to 7 degrees below average. Additionally, the weak troughing will maintain a deeper marine layer into at least the middle of next week.

AVIATION

252330Z...Coast/Valleys...Low clouds based near or just below 2000 ft MSL will return to coastal San Diego County starting 01-03z. Clouds spread northward and inland overnight, filling into most of the coastal basin by 11-13z. Portions of the Inland Empire may remain SKC. Minor vis reductions (3-6SM) expected for elevated inland valleys (KSBD, KRNM). Clouds clear toward the coastline 15- 18z Fri with SKC expected for the afternoon.

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 currently. Occasional MOD up/downdrafts in lee of mountains. Winds slowly weaken 06-12z. West-southest winds return slightly stronger Friday afternoon. Widespread gusts 25-35 kts with gusts 35-50 kts along desert slopes and through passes (locally higher through the Banning Pass).

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 through this evening with the highest surf on south facing beaches. See the Beach Hazards Statement for details.

FIRE WEATHER

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement until 10 PM PDT this evening for Orange County Coastal Areas-San Diego County Coastal Areas.

Wind Advisory from 11 AM Friday to 5 AM PDT Sunday for Apple and Lucerne Valleys.

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

Wind Advisory from 5 PM Friday to 11 AM PDT Sunday for San Diego County Deserts.

Wind Advisory from 11 AM Friday to 5 PM PDT Sunday for San Gorgonio Pass near Banning.

PZ...None.