textproduct: San Diego

SYNOPSIS

High temperatures peak on Saturday, before a slight cooling for early next week. Locally gusty offshore winds will continue through Saturday for mountains and foothills. Warmer conditions return for the middle to end of next week, with additional periods of Santa Ana winds.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

This evening...some thin high clouds moving over the northern portions of the region, otherwise skies are clear. Surface pressure gradients remain offshore and the wind-prone locations have reported easterly winds gusting 25-35 mph in the last hour. The dry airmass will enable temperatures to once again fall into the 30s at some wind-sheltered areas of the inland valleys tonight...unless enough high clouds move in to inhibit the radiation cooling.

From previous discussion... A slight strengthening of the winds is expected tonight into Saturday morning, with strongest winds most likely in foothills and canyons prone to easterly winds. Winds will slowly weaken into Saturday afternoon, with a brief return of weak onshore flow expected for Sunday and Monday.

Highs temperatures will peak on Saturday and are expected to be a few degrees warmer than today. Highs tomorrow are forecast to be 15 to 20 degrees above average for inland valleys and about 10 degrees above average for the coast, deserts, and mountains. Cooler conditions are expected on Sunday for the coast and valleys, with cooler conditions reaching further inland on Monday. Even with the cooling, highs Sunday and Monday will remain above average for this time of year. We may also see a return in low clouds and fog along the coast early next week with the break in prevailing offshore flow.

By Tuesday, all global ensemble guidance indicates a ridge of high pressure will rebuild over the US West Coast. The upper level ridge is expected to remain in place, and potentially strengthen, through the end of next week. This will bring another period of warm and dry weather to Southern California. NBM chances for highs exceeding 85 degrees are currently highest on Wednesday at 60 to 80 percent for the valleys and inland Orange County. Chances go down slightly Thursday but remain 50 to 60 percent. Chances of exceeding 80 degrees is near 100 percent on Wednesday for the valleys and inland Orange County and 70 to 80 percent for Thursday. The absence of marine layer influence for the middle to end of the week will allow coastal high temperatures to rise as well. A surface high is expected to form over the Great Basin for the middle to end of the week, bringing another period of offshore winds. Most of the latest ensemble guidance is indicating the offshore winds will be similar in strength to today and Saturday's. There does still remain some spread between ensembles in the strength of the winds, with 10 percent of the guidance showing the potential for a moderate to locally strong Santa Ana wind event.

AVIATION

310400...VFR conditions continue through the TAF period. Expect mostly clear skies with breezy northeasterly winds continuing in the foothills and below mountain passes and into adjacent valleys. Gusts up to 25-35 kts will be possible in these areas through Saturday evening.

MARINE

No hazardous marine conditions are expected through Wednesday.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...None.