Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 250418
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
918 PM PDT Sun Mar 24 2024

.SYNOPSIS...
Periods of rain, mountain snow, gusty winds, and cool conditions
will continue into this evening. Periods of gusty winds in the
mountains and deserts expected this week. Areas of drizzle
possible west of the mountains Tuesday morning. Conditions are
expected to gradually warm through the middle of the week. Another
storm system will likely bring additional rain, mountain snow,
and gusty winds to the area next weekend.

&&

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

No significant changes to the forecast package this evening as
showers and gusty winds continued to impact much of San Diego
County into the overnight hours.

Periods of rain and mountain snow are expected to continue through
the evening, mainly in San Diego County. Snow levels will remain
between 4500-5000 ft into tonight. Precipiation and wind gust
summaries are headlined on our weather.gov/sandiego homepage.

Gusty westerly winds will continue overnight, and are expected to
weaken as the storm moves through.

Conditions are expected to warm several degrees Monday and
Tuesday as the trough shifts east. Breezy conditions will
redevelop in the mountains and deserts during the afternoons and
evenings, with peak gusts 40-50 mph. A weak wave moving through
the northwest flow aloft and a marine layer about 5000 ft deep on
Tuesday may generate spotty drizzle or light showers along and
west of the mountains, again favoring San Diego County with lower
chances further north. Any accumulation will be less than a tenth
of an inch. Conditions will continue to warm into Wednesday as an
upper level ridge moves across the region with high temperatures
near normal.

A long wave trough moves towards the West Coast on Thursday, pushing
the ridge to the east. This is expected to kick off a cooling trend
for Thursday into the weekend. Highs on Thursday are forecast to be
a few degrees cooler than Wednesday west of the mountains, but still
a degree or two warmer in the deserts. Further cooling is expected
on Friday for all areas. Most ensemble guidance has backed off on
the idea of any precipitation with this initial wave, so PoPs remain
below 10%.

A wave on the back side of the upper trough eventually drops out of
the Gulf of Alaska and dives south as it closes off and eventually
moves inland somewhere across Central or Southern CA. Conditions are
expected to cool even farther for the end of the week and into the
weekend. Widespread precipitation is expected as the low moves
through, but there is uncertainty surrounding when and how much. The
GEFS and CME are on the faster end of the spectrum, bringing rain as
early as Friday night. The ECMWF is on the slower end, holding off
until later Saturday or even Sunday. Current forecast follows NBM
with chances of precipitation from late Friday night through Sunday
evening. There remains a lot of uncertainty in rainfall amounts,
with a wide range of solutions. For example, the NBM has rainfall
totals from one-tenth inch for the coasts/valleys on the lower end
of the spectrum to 1-2 inches on the high end. In addition to the
precipitation, much cooler and windy conditions, with periods of
mountain snow can be expected next weekend.

&&


&&

.AVIATION...
250400Z...Coasts/Valleys...SCT-BKN020-030 with -SHRA in San Diego
County through 08Z, then clearing through 12Z. Elsewhere...SCT050.
Monday 12Z-24Z...SCT030-050 SCT150.

Mountains...Locally obscured in clouds and pcpn through 12Z, mostly
in San Diego County. Aft 12Z...SCT-BKN060-080 SCT150.

Deserts...Gusty northwest winds 15-30 kt slowly decreasing through
12Z Monday. Northwest winds increasing again Monday afternoon to 15-
30 kt and continuing through evening.

&&

.MARINE...
A Gale Warning is in effect through early Monday morning for winds
of 20-30 kt gusting to 40 kts, and combined seas of 9-17 feet. Winds
over the Inner Waters will slowly diminish after midnight. Gusty
northwest winds are likely on Monday over the Outer Waters where a
Small Craft Advisory may be needed.

&&

.BEACHES...
A High Surf Advisory is in the effect for the San Diego County
Beaches and a Beach Hazards Statement is in effect for Orange County
through Noon Monday. A large swell from the west-northwest produce
breaking waves 4 to 7 feet, with sets of 8-10 in San Diego County.
The swell will subside Monday.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until noon PDT Monday for San Diego County
     Coastal Areas.

     Wind Advisory until 11 PM PDT this evening for Apple and Lucerne
     Valleys-Coachella Valley-Riverside County Mountains-San
     Bernardino County Mountains-San Diego County Deserts-San
     Diego County Mountains-San Gorgonio Pass Near Banning.

     Winter Storm Warning until 11 PM PDT this evening for Riverside
     County Mountains-San Bernardino County Mountains-San Diego
     County Mountains.

     Beach Hazards Statement through Monday morning for Orange County
     Coastal Areas.

PZ...Gale Warning until 6 AM PDT Monday for Coastal Waters from San
     Mateo Point to the Mexican Border and out to 30 nm-Waters
     from San Mateo Point to the Mexican Border Extending 30 to
     60 nm out including San Clemente Island.


&&

$$

PUBLIC...Suk/CO
AVIATION/MARINE/BEACHES...Moede


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