Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 272055
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
155 PM PDT Tue Sep 27 2022

.SYNOPSIS...
Hot conditions will continue across the region through tomorrow.
Increasing moisture will lead to a slight chance for showers and
thunderstorms on Wednesday across the mountains, High Desert and
eastern portions of the inland valleys. Greater cooling is
expected for Thursday through the weekend.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

A 590 DM is centered over the Southern High Plains today. Mostly
clear skies and rising heights will lead to warmer temperatures
west of the mountains today with highs generally 5 to 15 degrees
above average. Satellite water vapor imagery is starting to show
increasing moisture across Arizona with some cumulus development
across southeastern California, and moisture will continue to
make its way into Southern California. A stray light shower will
possible in the mountains this afternoon, though most areas will
remain dry.

For Wednesday, increasing moisture will lead to a slight decrease
in temperatures by a degree or two region-wide, though highs will
remain well above seasonal averages. This will continue to lead to
moderate to locally high heat risk across the region. Scattered
showers and thunderstorms will be possible through the afternoon,
mainly across the mountains, High Desert and eastern portions of
the inland valleys. The main threat will be frequent lightning and
gusty winds, though heavy rainfall leading to local flooding will
be possible.

The ridge will weaken on Thursday as an upper-low moves through
the Pacific Northwest. Onshore winds and drying conditions are
anticipated for Thursday through the weekend, allowing for cooler
temperatures. By Saturday, high temperatures are expected to be
near or slightly below average west of the mountains, and slightly
above in the deserts.

The 12z ECMWF Ens Mean shows ridging moving into the western
United States for the second half of the weekend, with positive
height anomalies returning to Southern California Sunday night
into Monday. This may lead to slight warming early next week.

&&

.AVIATION...
272030Z...Pockets of coastal low clouds west of KSAN through 06Z Wed
with bases 500-700 ft...otherwise clear.

06Z-17Z Wednesday...SCT-BKN004-007 vcnty KSAN and KCRQ with the most
widespread CIGS from 12-16Z and vis 1-4SM, lclly blo 1 mile in dense
fog.

&&

.MARINE...
No hazardous marine weather is expected through Saturday.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 8 PM PDT Wednesday for Orange County Coastal
     Areas-San Diego County Coastal Areas-San Diego County
     Valleys-Santa Ana Mountains and Foothills.

     Excessive Heat Warning until 8 PM PDT Wednesday for Coachella
     Valley-Orange County Inland Areas-San Bernardino and
     Riverside County Valleys-The Inland Empire-San Diego County
     Deserts-San Gorgonio Pass Near Banning.

PZ...None.

&&

$$

PUBLIC...Schenk
AVIATION/MARINE...Moede


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