textproduct: San Diego

SYNOPSIS

High pressure aloft and weak offshore flow will bring record- setting heat today. A return of onshore flow on Saturday will begin to spread cooler marine air inland but with record-setting heat continuing for many areas on Saturday. Cooling will continue through Monday, but with high temperatures remaining above average. There will be stronger and gusty west winds for Sunday and Monday afternoon and evening in the mountains and deserts with gusts 30 to 40 mph in the wind-prone areas. A little warmer and continued dry for Tuesday through Thursday of next week.

DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE

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

This morning...Temperatures are generally higher than at this time yesterday, and as much as 15 degrees higher in the coastal areas, as much as 10 degrees in the inland valleys, as much as 9 degrees in the mountains and as much as 6 degrees in the deserts. Surface pressure gradients are still offshore, and northeast to east winds gusting 20-35 mph in the wind-prone locations of the mtn passes and foothills. Variable high clouds continue under the extensive upper ridge of high pressure over the west coast. High temperatures today will be reach record or near-record levels for most areas today with many areas having high temperatures 20 to 25 degrees above seasonal averages. High temperatures for today will range from around 80 near the coast to the upper 80s to mid 90s for the valleys and inland Orange County with the lower deserts in the mid to upper 90s.

The ridge will begin to weaken and shift east in response to a low pressure system moving inland to our north. Onshore flow will return on Sat then strengthen for Sunday and Monday as the low pressure system moves inland to the north. This will bring noticeable cooling. Monday will likely be the coolest day with temperatures up to 5 degrees above average near the coast and inland areas. Monday high temperatures will range from the 60s to low 70s near the coast, lower to mid 70s for the valleys with the lower deserts in the low to upper 80s. Widespread record high temperatures and record warm overnight temperatures are expected for today through Saturday night with the near record high temperatures on Sunday mainly for the mountains and deserts.

The low pressure system moving inland through California into the Great Basin will bring gusty southwest to west winds to the mountains and deserts Monday afternoon and evening with the stronger gusts reaching 30 to 40 mph in the mtns and adjacent desert areas.

A weak, transient high pressure ridge will follow for Tuesday with a low pressure system moving inland to the north on Wednesday. This system will move toward the southeast after reaching the coast, but with differences on how far south it will go before moving farther east. High temperatures on Tuesday and Wednesday will be a few degrees warmer, then a few degrees cooler on Thursday. NBM shows increasing spread in the high temperature guidance for the coast and valleys for Tuesday through Thursday with the greater spread for the deserts for next Thursday and beyond.

AVIATION

271800Z...Mostly clear and VFR conditions will continue into Saturday morning. FEW-SCT high clouds AOA 25,000ft MSL. Patchy offshore low clouds may develop tonight, with less than a 10% chance for impacts at any coastal TAF sites.

MARINE

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.