San Diego Weather at Mission Trails, CA

000
FXUS66 KSGX 100409
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
909 PM PDT Sun May 9 2021

.SYNOPSIS...
A trough over the Rockies will maintain onshore flow with periods of
gusty westerly winds over the mountains and deserts through Monday.
Low clouds and patchy fog will be extensive nights and mornings west
of the mountains, clearing to the coast by afternoon. Weak high
pressure will build over the Southwest on Tuesday, bringing warmer
weather through the work week. Cooler weather likely returns by next
weekend.

&&

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

Low clouds were disorganized earlier this evening over the CA Bight
and onshore a few miles. The reason, unlike yesterday, there is no
eddy circulation. The clouds were slowly increasing in areal
coverage anyway, and were mainly below 2300 FT MSL, which was the
base of the inversion on our 00Z Miramar sounding. The sfc pressure
gradients were slowly increasing, supporting gusty winds through the
passes and into the deserts. Strongest winds were around 30 MPH with
gusts to 45 MPH.

Expect little weather change tomorrow with plenty of morning low
clouds west of the mountains, clearing to the coast by afternoon,
and fair, breezy conditions over the mts/deserts.

By Tuesday, some warming will begin as onshore flow decreases, and
high pressure over the far EastPac begins to drift east across CA.
The low clouds will be less extensive for the remainder of the week,
as the marine layer shrinks a bit under higher pressure aloft, but
still may not completely clear some coastal areas each afternoon.
Weaker onshore flow will then prevail until next weekend for a
warmer week ahead. Onshore flow will then increase as another trough
develops over the West next weekend. This will set up cooler weather
into next week, and maybe even some light precipitation. A number of
CMC/ECMWF ensemble solutions are wet over SoCal, while the GFS is
largely dry.

It is getting a bit late in the season, but certainly not unheard of
to get some winter-type systems this far south in May. Obviously a
precip event carries a lot of uncertainty, but the temperature
trends currently forecast, come with solid support of the ensemble
members of all the major global models. The warmest days will be
Wed/Thu as daytime temps rise to a few degrees above average.

&&

.AVIATION...
100350Z...Coast/Valleys...Areas of low clouds with bases 1600-2000
ft MSL and tops to 3000 ft MSL will fill in along the coast through
06Z and spread into the inland valleys by 08Z. Clouds clearing
inland 16-19Z. Areas along the coast and up to 5-10 mi inland likely
staying BKN through the afternoon, including KSAN and KCRQ, though
bases will generally be around 2000-2500 ft MSL. Clouds will begin
to spread back inland after 11/00Z with bases 1500-2000 ft MSL.

Mountains/Deserts...Mostly clear with unrestricted visibility
through Monday evening.

&&

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

&&

.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...10
AVIATION/MARINE...SS