034
FXUS66 KSGX 250424
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
824 PM PST Sun Nov 24 2024

.SYNOPSIS...
Temperatures will fluctuate between slightly below normal and
slightly above this week. Additional chances of precipitation
Monday for the High Desert and San Bernardino mountains. Rain
chances expand southward for Tuesday and Wednesday, with at least
slight chances for places in and west of the mountains. Periods
of gusty westerly winds for the mountains and deserts are expected
Tuesday into Wednesday. Dry conditions are expected for the
Thanksgiving holiday with another increased chance of
precipitation by the weekend.

&&

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

Evening Update...

High clouds above will continue to from west to east tonight off
the Pacific. This, in combination with light offshore flow
observed this evening, will increase chances for low clouds to
stay further offshore, though some may cover coastal areas by
early morning. We`ll bump it up a few degrees for folks along and
west of the mountains for your Monday. An area of low pressure
currently spinning off the coast of Oregon will move into Norther
California for the early part of next week. Latest thinking
remains the same far northern areas see the best chance of precip
by Monday morning and afternoon. Chances increase further south by
Tuesday and Wednesday, but model trends continue to sway a touch drier
for San Diego County.

Thanksgiving continues to look dry with models differing on the
placement and strength of an area of low pressure developing
somewhere off the coast, which may bring more light precipitation
into SoCal this weekend.

.Previous Discussion (137 PM PST Sun Nov 24 2024)...

The upper level pattern is expected to stay mostly zonal over
Southern California for Monday but a low pressure system digging
south along the Pacific Northwest will allow for heights to fall and
for moisture to reach the northern portions of our forecast area.
Latest guidance is indicating some light accumulating precipitation
is possible in the High Desert and San Bernardino county mountains
Monday. Based on current guidance it looks unlikely for
precipitation to make it to Orange County or the Inland Empire
Monday. A tenth of an inch or less of rain is expected for the High
Desert and western portions of the San Bernardino county mountains
on Monday. As the low pressure system moves east into the upper
Great Basin on Tuesday, weak troughing is expected over Southern
California which will allow the moisture to move south, reaching San
Diego county by Tuesday evening. Up to a tenth of an inch of rain is
expected to accumulate in Orange County, the Inland Empire, and the
San Bernardino county mountains for Tuesday through Wednesday
morning. There is a 10 to 20 percent chance some locations in
northern Orange County and Inland Empire could exceed 0.25", with a
35 percent chance of exceeding 0.25" of rain in the San Bernardino
mountains. Mostly light rain is expected for San Diego county, with
only a 5 to 10 percent chance of rainfall totals exceeding 0.10",
highest chances in northern San Diego county for Tuesday through
Wednesday morning.

In addition to periods of rain, westerly winds will increase for
Tuesday night into Wednesday. Winds will be strongest over the
mountains into the deserts. Peak gusts will be 35 to 45 mph, local
gusts up to 50 mph are possible in wind prone passes and canyons.
Snow levels for Monday through Wednesday are expected to stay above
8000 ft. Dry conditions are expected for Wednesday night into
Thursday with weak ridging over Southern California. Temperatures
will be near to slightly below normal through Wednesday, becoming
near to slightly above normal for the end of the week away from the
low deserts. In the low deserts temperatures will remain near to
slightly above normal for the forecast period.

There remains some uncertainty in the forecast for next weekend.
Global models are depicting a ridge of high pressure over the
Pacific Northwest with a trough of low pressure off the coast of
Southern California. Historically, this is a tricky set up for
models to depict correctly and global model ensemble solutions
continue to show differences in placement and amplitude of the
previously mentioned ridge and trough. Most model solutions are
leaning drier for Friday, although some individual members of the
GEFS and ECMWF still show the potential for precipitation,
especially for areas north of San Diego County. About 50 percent of
ensemble solutions are trending wetter for Saturday. Current
forecast for Friday and Saturday follows the NBM with slightly
higher chances of precipitation on Saturday vs Friday. Hopefully,
subsequent runs will bring more clarity on if the forecast will
trend drier and warmer or wetter and cooler for next weekend.

&&

.AVIATION...
250350Z...Coast/Valleys...SCT-BKN clouds at or above 10,000 ft MSL
continue to stream from the west to east tonight and Monday. These
will prevent widespread low cloud formation overnight, but very
patchy low clouds at 700-1000 ft MSL will be intermittently present.
Expecting impacts from low clouds to be minimal, with CIGs FEW-SCT,
but brief periods of BKN are possible through about 12Z tonight.

Mountains/Deserts...SCT-BKN clouds at or above 10,000 ft MSL
continue to stream from the west to east tonight and Monday, with
mostly unrestricted VIS through the period. Local west surface gusts
20-30kts will occur over mountain crests/desert slopes through
about 09Z tonight.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

PUBLIC...APR
AVIATION/MARINE...CSP