829
FXUS66 KSGX 221017
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
217 AM PST Fri Nov 22 2024

.SYNOPSIS...
Sunny, warm and dry weather will continue today. An atmospheric
river impacting Northern California will slide south into
Southern California Saturday, but it will weaken considerably.
Additional moisture arrives Monday and continues through Tuesday
possibly into Wednesday. Periods of light rain are expected
Saturday into early Wednesday, with greater rainfall north and
less rain south. Dry weather arrives by Wednesday or Thursday.

&&

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

Skies are clear again this morning, but there are a couple
patches of low clouds and fog along the coast. These will continue
to develop at the coast, but the day will be mostly sunny.
Onshore flow increases today, bringing cooler weather west of the
mountains as the marine layer rebuilds. More widespread low
clouds will develop and push ashore early this evening and move
locally inland by Saturday morning. An atmospheric river that has
been dropping copious rainfall on Northern California will
gradually sag southward today and Saturday. The moisture plume and
energy seem to fizzle somewhat on its southward journey. Skies
will cloud up Saturday with chances of light rain becoming
widespread. With no discernible trigger mechanism for getting
that moisture to turn into rain, the mountains will use their
orographic power to harvest the most rain. Except for isolated
foothills, there won`t be heavy or prolonged rainfall. Snow
levels will be way up, above 9,000 feet Saturday, but dropping to
around 7,000 feet by early Sunday. Snowfall will not accumulate
in mountain communities. This won`t be a particularly windy
system. The mountain ridges will get some strong gusts of 30-40
mph, but lower elevations won`t get strong winds. Sunday is
trending drier with recent model guidance. Overall, we`re in a
moist pattern and waves of moisture will come and go for several
days. Another plume of moisture arrives in SoCal Monday through
Tuesday. Pinpointing when and where rain will fall next week is a
tough problem. A broadbrush approach is probably best, with
chances of mostly light rainfall Monday into early Wednesday. Our
moist zonal pattern seems to buckle around Wednesday or Thursday,
which would put SoCal in a transient ridge and its corresponding
dry weather. Of course by that time there is a big spread in
model solutions. There are hints the wet pattern could redevelop
late next week, or we could stay dry for a while.

&&

.AVIATION...
220920Z...Coastal areas...Patchy low clouds with bases 700-900ft MSL
are expected 10Z-12Z. 65%-70% chance of CIG impacts at KSNA 11Z-17Z,
about a 50% chance of CIGs at KSAN 12Z-17Z and about a 35%-45%
chance at KCRQ 14Z-17Z. Local VIS 1-3SM on coastal mesas. Expect
clearing 17Z-18Z. Low clouds should push back ashore around 00Z-03Z
Sat, with likely higher bases and spreading farther inland.

Valleys/Mountains/Deserts...FEW-SCT clouds at or abv 20000 ft MSL
and unrestricted VIS through this evening.

&&

.MARINE...
No hazardous marine weather conditions expected through Tuesday.

&&

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

&&

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

&&

$$

PUBLIC...MM
AVIATION/MARINE...PG