textproduct: San Diego

SYNOPSIS

Cooler and breezy weather will occur this weekend as a weak weather system moves over the area. This system will bring gusty winds across the mountains and deserts along with the chance for some light precipitation along and west of the mountains as well. Next week will remain cooler with highs near to slightly below average and mainly dry weather.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

A zonal pattern aloft remains overhead, generating fair weather with temperatures near normal this afternoon. A weak area of low pressure is seen developing off the coast. This system, along with a shortwave from the north will move over our region Friday into the weekend. As it does so, the onshore pressure gradient will tighten, leading to an increase in winds across the mountains and deserts. Widespread westerly wind gusts of 25-45 MPH will be common across these areas Friday afternoon and night.

As the pair of systems draw closer to the region on Saturday, the pressure gradient will tighten further, leading to the highest winds of the event. Models show mountain winds 45-55+ MPH with desert winds 35-45 MPH, generating some blowing dust across the deserts at times. Model consensus is fair in light showers moving into the area as early as Saturday morning, mainly along the coastal slopes. The weather system will move over the area Saturday night into Sunday morning, giving way to the best chance of showers from the mountains to the coast. Hourly rain rates will mainly be near one tenth of an inch or less, with total accumulations below one quarter of inch west of the mountains. Snow levels will also drop near 6,500 feet, where there is high confidence that totals will remain below one inch. Sunday will be the coolest day of the week for many with highs 40s/50s across the mountains, 60s in the highest desert and coastal basin, and comfortable 70s in the lower deserts.

The troughing pattern will stick around for much of the week, which will lead to lighter onshore winds and temperatures near to slightly below average with dry weather. Models do hint at another weak area of low pressure forming in our vicinity by later on Tuesday or Wednesday, which may bring some increased wind and chances for precipitation. The forecast details still remain in flux as model timing and placement differences are present. After this, forecast models have better agreement on a dry weather pattern as we head into the month of May.

AVIATION

231800Z...Coast/Valleys...VFR prevails today under SCT-BKN high cirrus clouds. Patchy low clouds will struggle to reform tonight after 06z Friday with 30% chance of cigs over coastal airports. Best window for any CIGs will be between 12-17z. Should any CIGs form over the airports, bases will likely be between 1800-2400ft MSL.

Mountains/Deserts...Westerly winds gusting 25-35 kts through passes and along desert slopes expected to pick back up after 00z Friday. Local up/downdrafts in lee of mountains during periods of strong winds. Gusts gradually weakening after 09z Friday.

Otherwise...SCT high clouds today and tonight.

MARINE

No hazardous marine conditions are expected through Monday, though brisk westerly winds 15 to 20 kts are each afternoon, through Sunday.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

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