textproduct: San Diego

SYNOPSIS

High pressure over the region will bring very warm weather with record-breaking temperatures likely by Friday into Saturday. An area of low pressure will approach the State this weekend into early next week. This will bring greater cooling each day through Monday with elevated winds across the mountains and deserts and better chances for coastal fog each day. Weak high pressure returns by the middle of next week, where slight warming will be expected.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

A large area of high pressure is currently anchored over the central Baja California peninsula, as an area of low pressure spins far off the California coast. High clouds from the low are mainly over Northern California, with thinner cirrus clouds over our region. The ridge of high pressure will strengthen/amplify today into Friday, bringing hotter temperatures over the area. High temperatures will reach well into the 80s east of the 5 in Orange County and east of the 15 in San Diego County, with mid 90s into Coachella Valley. Not many records will be broken this afternoon, with areas of the lower deserts having the best chance to do so. Low continue to decrease off the coast this afternoon. Some of these may return by early Friday morning, but models show weak offshore flow keeping the clouds primarily offshore.

The ridge will peak in intensity on Friday with 850 mb temperatures rising near 21C. This accompanied with light winds over the region will allow our area to warm to 15-25 degrees above normal. Chances for highs to reach 100 degrees are low (10-25%) across much of the lower deserts, with closer to 50-60% across southern areas of the Coachella Valley. Highs will reach into the lower 90s for valleys west of the mountains. Multiple cities are expected to break records, including areas of the mountains will rise into the near 70 into the lower 80s. While some cities see records 5 degrees above the record, some cities may struggle to do so, especially coastal areas, including San Diego and Newport Beach. As the high begins to weaken, onshore flow will bring slight cooling west of the mountains. Plentiful 80s are still expected for the valleys and 70s near the coast, with the potential for daily record high temperatures to be broken yet again. Winds will also increase along the mountain desert slopes into the deserts with winds 20-35 MPH at times. These areas will see breezy conditions through next Monday.

The area of low pressure off the coast today will begin to move closer to the coast this weekend, bringing continued cooler weather by Sunday as it moves inland over Northern California. High across the mountains and western valleys will be around 10 degrees cooler by this time vs. Friday, around 5 degrees across the Coachella Valley. As the low pressure system moves over Northern California, the coolest weather of the week will occur by Monday and Tuesday. Highs will be near to slightly above average. The weather system will also bring a building marine layer with best chances for fog to return to the coastal areas by this weekend into early next week.

A weak area of high pressure will move over the region by early next week, bringing near average temperatures. Another area of low pressure is expected to move in from the north by Wednesday into Thursday of next week. Models continue to show a trend of the system moving further inland, where the chance for any precipitation continues to decrease. High pressure off the coast will also build slightly during this time as well, so we are looking more likely to see slight warming with continued drier weather. As the low pressure system passes by the region, we will also have to keep an eye on Santa Ana winds that may show up by the end of next week.

AVIATION

270000Z...Coast...Mostly clear skies out there with a few high clouds passing by around 20k-25k feet MSL. VFR conditions are expected through the TAF period with patchy fog and a few low clouds around 200-400 feet MSL along the coast after 06Z. Patchy fog is not expected to be impactful to coastal TAF sites.

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.