San Diego Forecast Discussion

FXUS66 KSGX 220431

Area Forecast Discussion
National Weather Service San Diego CA
930 PM PDT Tue Mar 21 2023

Occasional rain, snow and gusty winds will continue over Southern
California through Wednesday night as a powerful spring storm moves
slowly inland. Precipitation will wind down on Thursday, setting up
A period of dry, and continued cool weather through the weekend.
Another low pressure system dropping south across the West, could
bring more precipitation by the middle of next week.



-The Zone Forecasts, Warnings and Advisories have been updated. The
Flood Watch remains in effect.

An organized line of moderate rainfall swept inland earlier this
evening, adding another one-quarter to one-half inch of rain to many
sites west of the mountains. Scattered showers remain, and will
likely continue through the night. Locally heavy rain is still
possible near any of the heavier showers or thunderstorms that may
develop. Please see our webpage for all the latest storm reports,
Rainfall totals, and the Advisories and Warnings still in effect at

A deep low pressure center near San Francisco will slowly weaken
overnight, but continue to spread showers and gusty winds over large
portions of the State through Wednesday. Precipitation should wind
down on Thursday, as the last disturbance associated with this storm
drops SE, allowing the parent trough to drift farther inland.

A broad trough will remain over the West for the remainder of the
week, holding temperatures in check, but keeping any further
significant precipitation well to the north. This weekend, northerly
flow down the west coast of Canada, will steer another wave to just
off the PacNW Coast by Monday. The track of this system remains to
be confirmed, but it looks like at the very least, it will keep our
temperatures below average into next week, and could even bring more
precipitation. This is evident in the spread of ensemble solutions
of all of our major global models. We will have to wait to see how
they coalesce in the coming days to see just how this system might
impact us.


220330Z...Coast/Valleys/Mountains...SCT -SHRA is expected through
the evening into much of Wednesday. SCT-BKN clouds low clouds with
bases mostly 3500-6000 ft MSL, closer to 2500 ft MSL in heavy rain
with vis reduced 1-3 sm at times. Widespread terrain obscurations
will prevail through tonight. Southwest winds will weaken for
coastal and valley areas sticking near 20 kts, though still be quite
strong across the mountains through Wednesday with gusts 30-45 kts.
Snow levels lowering tonight, with -SHSN continuing through the night
into much of Wednesday across the mountains.

Deserts...ISO -SHRA before midnight, with drying through early
morning. Some areas may see ISO -SHRA Wednesday afternoon. Southwest
winds on desert mountain slopes and locally into the deserts will
lower, with gusts 25-35 kt with MOD UDDFS and LLWS over/northeast of
the mountains. BKN-OVC bases 3000-5000 ft MSL, locally 1500-2000 ft
MSL with clouds lifting to above 5000 ft MSL after midnight.


A pacific storm will bring southerly gales and hazardous seas into
Wednesday. There is a chance of thunderstorms and waterspouts
tonight and Wednesday morning. Check the Gale Warning for details
and stay tuned for any special marine weather bulletins that may be
issued. Winds and seas will gradually subside late Wednesday.
Northwest winds will increase again for Thursday through Saturday in
the outer waters, which would bring more hazardous winds and choppy


A Pacific storm will bring large short-period swells and surf
tonight through Thursday. Breakers will range from 4 to 8 feet, with
sets up to 10 feet in southern San Diego County. This will produce
hazardous swimming conditions and local beach erosion. Swell and
surf should subside Thursday. Check the High surf advisory for



After this evening, showers will become more scattered and
intermittent through Wednesday night. This will help to diminish the
flood threat at lower elevations. In the meantime, a Flood Watch
remains in effect.

The snow level will fall from between 4500 and 5000 feet this
evening, to 4000/4500 feet by Wednesday morning.

Additional rainfall and liquid equivalent above the snow level
through Thursday morning is expected to range from around 0.5 to
one inch coast/valleys, to 1 to locally 3 inches in the mountains.
One-tenth to one-half inch additional is possible for the deserts.

The Santa Margarita and San Diego Rivers are forecast to crest at
minor flood stage at 3 AM PDT overnight, then trend lower through
Thursday. Low-lying roads near the rivers will be impacted. Other
areas of concern are the Mojave River, which is flowing within it`s
banks; the Whitewater River, and Coachella Canal in the Coachella
Valley, which is expecting to see some flow; and possibly low-lying
areas in the Tijuana River watershed.


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


CA...Flood Watch through Wednesday evening for San Diego County
     Coastal Areas-San Diego County Mountains-San Diego County

     High Surf Advisory from 2 AM Wednesday to 9 PM PDT Thursday for
     San Diego County Coastal Areas.

     Flood Watch through Wednesday afternoon for Orange County
     Coastal Areas-Orange County Inland Areas-Riverside County
     Mountains-San Bernardino County Mountains-San Bernardino
     and Riverside County Valleys-The Inland Empire-San Gorgonio
     Pass Near Banning-Santa Ana Mountains and Foothills.

     Winter Storm Warning until 5 AM PDT Thursday for Riverside
     County Mountains-San Bernardino County Mountains.

     Winter Weather Advisory until 5 AM PDT Thursday for San Diego
     County Mountains.

     High Wind Warning until noon PDT Wednesday for Apple and Lucerne
     Valleys-San Diego County Deserts-San Gorgonio Pass Near

     Wind Advisory until 10 PM PDT this evening for Coachella Valley.

     High Surf Advisory from 2 AM Wednesday to 9 AM PDT Thursday for
     Orange County Coastal Areas.

PZ...Gale Warning until 9 AM PDT Wednesday 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.




NWS SGX Office Area Forecast Discussion