textproduct: San Diego

SYNOPSIS

A warming and drying trend is expected through this weekend as weak zonal flow returns to the region. Therafter, temperatures will hover slightly above seasonal averages through next week. Marine layer clouds expected for coastal areas and western valleys each night and morning. Clouds may lower and become more confined to coastal areas by early next week.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

As our most recent low pressure system departs to the east, low clouds and fog are starting to disperse along coastal slopes and elevated winds along the desert slopes are starting to abate. Satellite imagery shows that marine layer clouds are struggling to develop under a weak inversion tonight. However, a return to quasi-zonal flow will allow the inversion to strengthen by tomorrow. Thus, marine layer clouds should return to coastal areas and western valleys from Saturday night onward. Weakening onshore flow and slowly increasing upper heights may allow the marine layer to become shallow enough for patchy fog for coastal areas by early next week.

Temperatures will rebound to near seasonal averages on Saturday with highs near 70 at the coast, upper 70s to low 80s for inland valleys, and 90s in the lower deserts. A slow warming trend will continue into Sunday. Thereafter, the deserts will continue to warm through early next week while the coastal basin cools a few degrees. Overall, temperatures will hover around 2-7 degrees above seasonal averages across the region through mid-next week with minor flucutations each day. NBM temperatures reach up to 105 in the lower deserts mid-next week, though a lack of any notable ridging begs the question of whether temps may be slightly overdone.

By late next week, model solutions diverge. An upper trough is expected to pass through the NW CONUS late next week, but the timing, position, and amplitude are all quite uncertain at the moment. The mean of the ensembles leans toward a cooling trend for late next week into the weekend, but not much can be said beyond that at this time.

AVIATION

300330Z...Coast...SCT-BKN low clouds based around 1500-1800 feet MSL will gradually increase overnight. Scatter out Saturday by 16-17Z. Low clouds based around 1000-1500 feet MSL to gradually develop after 03Z Saturday evening.

Valleys/Mountains...BKN clouds based 4000-5000 feet MSL mainly near foothills will continue to gradually clear overnight. Areas of low clouds based around 2000 feet MSL and very localized vis reductions 4-6SM in western valleys 11-16Z. Otherwise, mostly clear, except for some cumulus around 9000 feet MSL over mountains 19-00Z Saturday.

Deserts...Mostly clear and VFR conditions through Saturday. Westerly wind gusts 25-30 kts east of mountain passes gradually diminishing after 07Z.

MARINE

Northwest wind gusts will approach 20 kts over outer coastal waters Saturday afternoon and evening. Otherwise, no hazardous marine conditions are expected through Tuesday.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

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