Cmp Pendleton, California Weather Forecast Discussion

370
FXUS66 KSGX 281619
AFDSGX
Area Forecast Discussion
National Weather Service San Diego CA
919 AM PDT Sun Sep 28 2025
.SYNOPSIS...
Slight chances of showers and thunderstorms over the mountains
this afternoon, then dry weather for the remainder of the week.
High temperatures remain well below normal with a deep marine
layer through Tuesday. Gradual warming expected Wednesday through
the end of next week with a shallower marine layer.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Update: Satellite as of 8:45 AM shows low clouds covering the
coastal basin. These clouds will gradually clear through 1 PM,
yielding to partly cloudy skies and high temperatures 5 to 10
degrees below average for inland areas. Cumulus clouds will
develop over the mountains and with some weak leftover
instability still present, a shower or two with light rain rates
cannot be ruled out this afternoon. Otherwise, another deep marine
layer is expected to fill the coastal basin with low clouds this
evening into tonight.
Previous discussion from 2:55 AM...
Water vapor imagery shows the center of the upper low moving east
into western Arizona. A few light showers continue to wrap around
the north side of the low into northern San Bernardino and Kern
Counties, but are remaining out of our forecast area. The marine
layer is about 4000 ft deep based on the 00Z KNKX sounding and low
clouds have filled in across most areas west of the mountains,
except a strange clear slot over southwest San Diego County. This
will continue to fill in through the morning, followed by at least
partial clearing this afternoon. Some residual mid-level moisture
hangs around today for a slight chance of showers and
thunderstorms over the mountains this afternoon. Latest hi-res
models have backed off on rainfall rates, generally around one-
quarter inch per hour or less, so any flooding threat is minimal.
Otherwise cool today with highs several degrees below normal.
For Monday, the upper low over AZ continues to lift out and
short-wave ridging moves over So Cal for very minor warming and a
slight decrease in the marine layer depth. The is short lived as a
short-wave within the mean trough off the coast moves across the
West Coast, bringing minor cooling and breezy winds in the
mountains and below the passes.
Ridging amplifies across northern Mexico into the Desert Southwest
Wednesday and Thursday for another minor warming trend, bringing
highs closer to seasonal normals. Some uncertainty is introduced
into the forecast beyond Thursday as ensemble spread increases on
the timing and depth of the mean trough axis as it tries to
progress eastward. In general there will be a cooling trend into
the end of the week with more widespread low cloud coverage, but
the degree to which these things occur will depend on the details
of the trough placement. Currently the difference in the NBM 10th
and 90th percentile max temperatures for the Friday and Saturday
timeframe is on the order of about 8 degrees for inland areas.
&&
.AVIATION...
281540Z....Coasts/Valleys/Foothills...Low clouds based 2000-4000 ft
MSL will clear the coastal basin through 20Z. Low clouds 1500-2500
ft MSL develop along coastline after 03Z Mon, starting in San Diego
County then moving north and into inland valleys, including
KONT/KSBD, by 12Z Mon. Vis restrictions of 2-4 SM BR where low
clouds intersect higher coastal terrain. Low clouds and any
vis restrictions expected to scatter out 17-19Z Mon.
Mountains/Deserts...10-20% chance iso -SHRA along with 10% chance
for TSRA mostly over the mountains 20-00Z. Otherwise, VFR conditions
with cu based 7-10k ft MSL over mountains in the afternoon.
&&
.MARINE...
No hazardous marine conditions are expected through Friday.
&&
.BEACHES...
South swell from Hurricane Narda will reach Southern California
coast by this afternoon. 4-5 feet swell with a period of 12-14
seconds will produce elevated surf and a high rip current risk
through Tuesday. Surf of 4-7 feet with sets 8 feet on south facing
beaches expected. Strong longshore currents will impact all beaches.
More information can be found in the Beach Hazards Statement.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Tuesday evening for Orange
     County Coastal Areas-San Diego County Coastal Areas.
PZ...None.
&&
$$
PUBLIC...Westerink
AVIATION/MARINE/BEACHES...CO

NWS SGX Office Area Forecast Discussion