March Air Force Base, California Weather Forecast Discussion

568
FXUS66 KSGX 192032
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
132 PM PDT Fri Sep 19 2025
.SYNOPSIS...
Isolated thunderstorms off the San Bernardino Mountains and High
Deserts today before drier and warmer weather into Saturday.
Tropical moisture moves up Sunday morning with periods of heavier
rain showers into Sunday evening, especially across San Diego
County and the mountains. Lesser rain/storm chances after Sunday
which will be more confined to the mountains, and more seasonable
temperatures prevail with ample cloud cover and moisture.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Water vapor imagery shows a large upper level low sweeping down
along the California coast with weak ridging over the region,
setting up southwest flow and squashing some of the better moisture
we`ve had the past few days. As such, storm and shower activity this
afternoon will be very limited as the lower levels dry out, but a
few thunderstorms off the San Bernardino Mountains that then move
into the High Deserts will not be out of the question, with
significantly lower rainfall rates than those seen yesterday. Any
storms that manage to develop today will come to an end or move out
of the region by sunset, with drier weather prevailing thereafter.
Given lower dew points and less cloud cover tonight and tomorrow,
more seasonable temperatures ensue, with highs in the 70s and 80s
for coasts/valleys, 60s and 70s for the mountains, and upper 90s for
the deserts. On Sunday, tropical moisture once again pushes up into
Southern California from a developing system off of Baja. Hi-res
models are pulling the moisture up as early as Sunday morning,
spreading over San Diego County and then up into Riverside, Orange,
and San Bernardino counties by the afternoon. Soundings show
significantly drier air in the lower levels with most of the
moisture elevated, indicating better rainfall chances will be in the
mountains, but isolated spots of 0.50" rainfall totals throughout
the day Sunday are not out of the question. This pattern is
especially difficult to resolve and confidence in how far north the
moisture makes it as well as the drier air at the lower levels will
make or break this event. Regardless, better moisture and ample
cloud cover should make for slightly cooler temperatures on Sunday
compared to Saturday.
Additional moisture will surge into the region Monday-Wednesday,
with less confidence in the overall upper level pattern. Rain
showers will be possible during this time, with thunderstorm chances
returning primarily for the mountains by Monday afternoon and
becoming more widespread on Tuesday. At this point the spread in
models is a bit too great to nail out the details, but confidence in
precipitation/storm chances will be highest in the mountains for the
Mon-Wed time frame. With the incoming clouds and moisture,
temperatures will hold fairly steady into the end of next week.
&&
.AVIATION...
191530Z....Coast/Valleys...Ceilings have scattered out for this
afternoon with IFR to LIFR ceilings returning along the coast around
01z-02z for San Diego County and arriving at Orange County coast
around 04z-05z tonight into tomorrow morning. Minor vis reductions
will be possible along higher coastal terrain in the late evening
around 06z to the late morning hours around 16Z Saturday. Ceiling
will slowly begin to lift around 17z.
.
.Mountains/Deserts...VFR conditions expected through the TAF
period with some SCT mid level clouds based 5000-10000 ft MSL
lingering through the late afternoon today. MVFR vis will be
possible around 15z-18z around KSBD Saturday. Otherwise SKC at
Inland sites.
&&
.MARINE...No hazardous marine conditions are expected through
Wednesday morning.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
PUBLIC...Zuber
AVIATION/MARINE...Villafane

NWS SGX Office Area Forecast Discussion