textproduct: San Diego

SYNOPSIS

Below average temperatures with limited marine layer low clouds and fog this morning. Low clouds and fog return with more coverage tonight into Sunday morning, spreading into portions of the valleys. Gusty westerly winds expected in the mountains and deserts this afternoon and evening. Warming trend expected Monday through at least the middle of next week. Areas of major HeatRisk possible for the deserts and moderate HeatRisk for inland Orange County, valleys, and mountains mid next week. The marine layer will become shallower next week, staying confined to coastal areas.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

This morning...There is a lot less low cloud coverage than at this time yesterday, likely due to onshore pressure gradients trending weaker. The low clouds will increase in coverage over the next 6 to 8 hours before clearing out, although they will likely remain limited to the coastal areas and valleys of San Diego County.

Weak upper level troughing over the western states and onshore flow will keep daytime temperatures near or several degrees below normal through Sunday. The marine layer will remain relatively deep with low clouds and fog spreading up to 20 miles inland tonight into Sunday morning. The onshore flow will produce westerly winds gusting 25-45 mph in the mtn passes and adjacent desert areas this afternoon/evening and again Sunday afternoon/evening.

A warming trend is expected for Monday through mid-week as high pressure builds over the western states. Current model solutions show that Wednesday will be the warmest day overall with high temperatures 5 to 12 degrees above average and areas of moderate HeatRisk away from the coast and areas of major HeatRisk in the low desert. Some guidance is indicating an increase in moisture aloft for the middle of next week. This could bring lower than expected daytime temperatures and higher than expected overnight low temperatures. The high pressure aloft will also result in a shallower marine layer with overnight low clouds and fog mostly restricted to the coastal areas.

Numerical model guidance is coming into better agreement with respect to the pattern late next week. A majority of ensemble members now show some weak troughing aloft approaching the west coast. This could result in a slight cooling trend as we approach the end of next week. By next Friday, daytime temperatures could be near or a little below normal west of the mtns and 2-7 degrees above normal in the deserts.

AVIATION

200630Z...Coast/Valleys...Low clouds are getting a late start this evening with just a finger of low clouds around 1500ft MSL poking into KCRQ. Low clouds with bases 1500-2000ft MSL will slowly form over the next few hours, mainly over San Diego COunty, but is expected to be patchy in nature and not to the same extent as was seen last night. Inland vis restrictions 1-5SM will be possible where low clouds intersect terrain. Low clouds will scatter out 16- 19Z. Low clouds redevelop after 01Z Sunday beginning over coastal SD County.

Mountains/Deserts...VFR conditions expected through the TAF period. Breezy westerly winds with gusts 30-45 kts, locally 50 kts through mountain passes into deserts through 10Z. Local vis reduced in BLDU. Moderate up/downdrafts in lee of mtns. Westerly winds 30-40 kts redevelop through mountain passes into deserts after 18Z.

MARINE

No hazardous marine conditions are expected through Thursday.

BEACHES

Elevated surf and strong rip currents continue through Sunday and potentially longer. Surf of 3-5 feet with local sets to 6 feet are expected at south-facing beaches. Expect locally hazardous swimming conditions with high rip current and longshore current risk. See the Beach Hazards Statement for more details.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement through Sunday evening for Orange County Coastal Areas-San Diego County Coastal Areas.

PZ...None.