Area Forecast Discussion
Issued by NWS San Diego, CA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
000
FXUS66 KSGX 221613
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
913 AM PDT Fri Mar 22 2024

.SYNOPSIS...
Cooler conditions today with periods of both high and low clouds.
Periods of rain, mountain snow, and gusty westerly winds are
expected this weekend. Drier with warming for Monday and Tuesday. A
low pressure system from the northwest could bring additional
precipitation Wednesday night. A more substantial storm is possible
toward the end of next week, but there remains a lot of
uncertainty in the details.

&&

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

Visible satellite imagery at 9 AM was showing low cloud coverage up
to 20 miles inland. Areas of fog are still being reported along
the coast and near higher coastal terrain. Low clouds and fog are
expected to clear through the morning, with areas of high clouds
expected to linger through much of today. Cloud coverage will
increase into Saturday ahead of an incoming low pressure system.
This weather system will bring cooler, wetter, and windier
conditions to Southern California with periods of mountain snow
down to 4500-5500 ft. More details on rain and mountain snow can
be found in the Hydrology section below.

Periods of gusty westerly winds are expected Saturday into Sunday.
Breezy southwesterly winds are expected along the coast ahead of a
passing weakening cold front late Saturday morning, becoming
northwesterly as the front passes from north to south. Gusty
northwest winds are expected along the coast after the front passes
Saturday night into Sunday night. Peak gusts of 30 to 45 mph
expected, with the strongest winds looking to be Sunday afternoon.
Gusty westerly winds are also expected on the desert mountain slopes
into the deserts. Strongest winds will be Saturday evening into
Sunday morning, with peak gusts 55 to 65 mph.

High temperatures today will be similar to a few degrees cooler than
yesterday, with further cooling into the weekend. Conditions will be
5 to 10 degrees below average for coastal areas, 10 to 20 degrees
below average for the valleys and deserts, and 15 to 20 degrees
below average for the mountains this weekend. The coolest day for
inland areas will be on Sunday. Monday and Tuesday will be warmer
and drier with northwest flow aloft. High temperatures on Tuesday
will be around 5 degrees below average for lower elevations to
around 10 degrees below average for the mountains.

A low pressure system from the northwest could move across the area
sometime Wednesday night and Thursday with a slight chance for
mostly light precipitation. Unsettled weather looks to continue
into next weekend with another stronger low pressure system making
its way towards the Western US with low confidence in details.

&&

.HYDROLOGY...

A weakening cold front will move southward across the area on
Saturday bringing periods of precipitation. Latest high resolution
guidance indicates the front will move from Orange County south and
east into San Diego County from early Saturday afternoon into
Saturday evening. Periods of moderate rain are expected during that
time, with guidance indicating rain rates will be 0.25-0.35 inches
per hour. After the front passes, shower coverage will become more
scattered. Showers will be moderate to locally heavy at times as a
couple shortwaves move through Southern California Saturday night
into Sunday morning and again Sunday afternoon and evening. The
majority of the shower activity on Sunday is expected to be in San
Diego County and in the mountains. There is a slight chance of
thunderstorms for late Saturday night into Sunday evening. Showers
will taper off from northwest to southeast into Monday morning.

For Orange, southwestern San Bernardino, and western Riverside
Counties, rainfall is expected to range from one-quarter to one-
third inch near the coast to 1 to 1.5 inches in the mountains,
locally up to 2 inches possible. For San Diego County, rainfall is
expected to range from one-half to three-quarters of an inch near
the coast to 1 to 2.50 inches in the mountains. There are some
uncertainties in rainfall amounts, mainly for locations in San Diego
County on Sunday. 40% of ensemble members are showing 1 inch of
rainfall Saturday night into Sunday night for southern San Diego
County.

A snow level of 6500 to 7000 feet for Saturday morning will fall to
around 4500 feet for early Sunday morning, then fluctuate between
4500 and 5000 feet for Sunday afternoon and evening. Snowfall of
less than 3 inches is expected below 5000 feet, 3 to 6 inches from
5000 to 6000 feet, 6 to 12 inches from 6000 to 7500 feet, with
locally 12 to 18 inches above 7500 feet.

&&

.AVIATION...
221530Z...Coasts/Valleys...Low clouds based at 300-800 feet MSL with
tops to 1400 feet and vis 0-5SM will scatter out by 17-18Z. Low
clouds will redevelop and push ashore after 03Z and farther inland
overnight. Bases will start at 800-1500 feet MSL and will rise
through Saturday morning, some areas over 2000 feet MSL. Clouds
should fill the coastal basin, extending to and obscuring some
foothills, by 11Z Saturday.

Mountains: SCT to locally BKN clouds at/abv 20000 feet MSL with
unrestricted VIS through Saturday morning. Except coastal foothills
below 4000 feet MSL should receive low clouds and fog with partial
obscuration after 11Z Saturday.

Deserts: SCT to locally BKN clouds at/abv 20000 feet MSL with
unrestricted VIS through Saturday morning.

&&

.MARINE...
No hazardous marine conditions are expected through Saturday
morning. Strong northwest winds will generate hazardous conditions
for Saturday afternoon through Monday. A Gale Watch has been issued
from Saturday afternoon through Monday morning. The strongest winds,
gusting 30-35 kts, and combined seas of 9-13 feet are expected late
Sunday. Conditions will improve Monday.

&&

.BEACHES...
Large short-period swell from the west-northwest will arrive early
Sunday, peak Sunday night, and subside Monday. This storm swell will
likely produce breaking waves 4 to 7 feet, with sets up to 8-10 feet
Sunday night, highest in southern San Diego County.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 8 AM Saturday to 11 PM PDT Sunday 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 Watch from Saturday morning through Sunday evening
     for Riverside County Mountains-San Bernardino County
     Mountains.

PZ...Gale Watch from Saturday afternoon through late Sunday night 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/HYDROLOGY...CO
AVIATION/MARINE/BEACHES...MM


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.