textproduct: San Diego

SYNOPSIS

Gradual cooling through the weekend with a return of marine layer low clouds and fog at the coast. Even with the cooling, temperatures will remain 15-25 degrees above normal into next week, highest on Wednesday during the next peak in the heat.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

Today through tomorrow night...

Currently, low clouds are still nearly absent within the inner waters of the SoCal bight, and will likely continue to struggle to develop throughout the morning, with likely just some patchy low clouds and fog being possible along some of the coastal areas, with higher confidence along the southern coast of San Diego County.

The very strong ridge overhead that has resulted in record-breaking heat is finally going to begin to weaken and allow for some relief in the intense heat, although temperatures will still be well above average for this time of year. The low deserts still have an Extreme Heat Warning in place for today as temperatures still look to approach 110 for some areas. There will be an enhancement in onshore flow, bringing a slight cooling trend from west to east through tomorrow. This will help to knock down high temperatures nearly 10 degrees cooler from where they were yesterday for some of the inland areas by Sunday. This will also help to some of the lower level moisture to surge in from the west as there is some weak troughing upstream which will help to influence the marine layer with better coverage expected overnight Saturday into Sunday morning. There could also be some patchy fog, which may even be locally dense along some of the coastal slopes. Winds will become stronger and gusty out of the west by later this afternoon and through the early evening, especially across the higher terrain and within the mountains passes and canyons which are more vulnerable to gusty winds. These winds look to primarily remain below criteria, and will be gusty again during the afternoon hours on Sunday, although even slightly weaker.

Monday through Friday...

As the ridge continues to break down, the longwave flow will become more zonal, then followed by more ridging (although not as strong as the ridge in place this past week) going into the latter part of the week, which will bring back a gradual warmup and keep temperatures still some 15 to 20 degrees above the seasonal average for this time of year, especially within the inland valleys and IE. There is pretty good agreement with the ensemble solutions showing slight ridging becoming the dominant feature again, and then a little beyond the forecast shows that there could begin a pattern shift going beginning the following weekend, although this is still too far out in the forecast to be reliable at this time.

AVIATION

211100Z...Mostly clear skies and VFR conditions across the region currently. Patchy fog may develop near the coastline after 12Z, though coverage looks to be less than previously anticipated. Any FG that develops will stay mostly within 5 miles of the coastline. 40% chance for vis below 1SM at KSAN, 20% at KCRQ and KSNA. Scattering out of land areas 15-17Z, but may linger at the beaches through 20Z. Low clouds return to coastal areas tonight with slightly higher bases. Minor vis reductions (2-5SM) for coastal areas with FG along elevated coastal terrain.

MARINE

Chance for patchy fog (30-40%) near the coastline after 12Z this morning, locally reducing visibility under 1 nautical mile. If any FG develops, local vis reductions will improve by late this morning. Otherwise, no hazardous marine conditions expected through Wednesday night.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...Extreme Heat Warning until 8 PM PDT this evening for Coachella Valley-San Diego County Deserts-San Gorgonio Pass near Banning.

PZ...None.