textproduct: San Diego

SYNOPSIS

Fair and seasonal weather will continue for the coming week, with a gradual warming trend. The marine layer will gradually decrease in depth with night and morning low clouds not spreading as far inland nor lasting as long. Subtropical moisture will bring some higher level clouds this holiday weekend, but with seasonal temperatures.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

Our deep marine layer covered the entire coastal basin in clouds this morning. In what has become a typical pattern over the last couple weeks, low clouds cleared this morning in San Diego County before Orange County and much of the Inland Empire. Also, typical of this recent marine layer pattern, clouds will move ashore and inland in San Diego County early this evening, while developing much later in Orange County and the Inland Empire. High pressure aloft softly and gradually builds over the next week. However, the low clouds by Friday morning will not have the extent of overall coverage as they did this morning. On Saturday, the fourth of July, copious high level subtropical moisture arrives from the south. With no real triggers to lift this moisture to produce showers or thunderstorms, there is less than a slight chance of any preciptation with this moisture this weekend. Upper levels dry out Sunday night and Monday. The marine layer will get disrupted by the high level moisture this weekend, and the higher pressure aloft will suppress it. These factors will combine to reduce the spatial coverage and duration of coastal clouds. Friday morning will already begin the decreasing low cloud trend, continuing through the weekend. Low clouds should become more uniform again for Monday morning, as the upper level disruption exits. Models and associated ensembles agree on higher pressure aloft next week over the Southwest, but disagree on the timing, location, and strength of this upper ridge. With confidence, we believe there will be a warming trend next week, felt most noticeably in the mountains and deserts, where temperatures will rise to about 4-8 degrees above normal. On Wednesday, our forecast high temps show 110-113 degrees for the low desert, 96-102 for the high desert, and 90-100 for the Inland Empire. This time of year, that means a moderate HeatRisk for the deserts, with isolated major levels in the lower deserts Tuesday and beyond. The marine layer, reestablishing itself after the weekend disruption, will continue to moderate temperatures in coastal areas and valleys, remaining only a few degrees above seasonal.

AVIATION

030000Z....Coast/Valleys...SKC and VFR throughout the coastal basin. Low clouds based around 1200-1800 ft MSL are expected to develop around 02z at the SD County coast, slowly filling into SD County inland valleys through 07z, then filling into Orange County 07-12z. Confidence has decreased for cigs in the Inland Empire tonight: 40% chance for KONT and 25% chance for KSBD, between 12-16z. Patchy VIS reductions down to 3-6SM in eastern valleys and IE valleys. VIS improves and clouds scatter out 15-18z Friday. VFR Friday afternoon.

Mountains/Deserts...Clear skies with unrestricted VIS through Friday afternoon.

MARINE

No hazardous marine conditions are expected through Monday.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

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