Pomona, California Weather Forecast Discussion

327
FXUS66 KLOX 052344
AFDLOX
Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
444 PM PDT Fri Sep 5 2025
.SYNOPSIS...05/1216 PM.
Temperatures are expected to be within a few degrees of
normal today through the weekend. Then next week much cooler
weather is expected as a low pressure system approaches
California.
&&
.SHORT TERM (TDY-MON)...05/230 PM.
The current benign weather pattern will continue through the
weekend as a weak upper ridge hangs out over Southern California.
Temperatures will remain near normal with minimal day-to-day changes,
while coastal locations experience night through morning low
clouds and patchy fog (even pushing into the valleys at times).
Some low clouds and fog are also expected in the southern Salinas
valley during the morning hours. As for winds, Sundowner winds
will start to pick up Sunday night across the southwestern Santa
Barbara Coast, where gusts up to 40 mph will be possible.
An upper level low pressure system will start to move over the
Pacific Northwest on Monday, with a trough extending southward
over the entire West Coast. As a result, quite a bit of cooling
will start to occur on Monday, with high temps dropping 3-6
degrees below normal, while low clouds and fog push into the
valleys during the night and morning hours.
.LONG TERM (TUE-FRI)...05/226 PM.
Good model agreement continues to show a cooling trend through at
least mid week with the biggest decrease in temps on Tuesday,
when highs drop to 6-12 degrees below normal, especially inland
where highs in some areas may not even reach 80 degrees. There may
even be some drizzle up against the coastal slopes as the marine
layer deepens and reaches at least 3000 feet, especially later in
the week.
Model agreement starts to fall off a bit late next week. While a
majority of the longer range model solutions show a slow warming
trend beginning later next week, some of the more recent solutions
are now favoring well below normal temperatures continuing
through at least next Friday, and then only a very slow warming
trend into the week of the 14th.
Additionally, as the trough continues to move through the
region next week, the GFS and ECWMF deterministic runs and several
members of their respective ensembles are hinting at a low
pressure system dropping into the region, followed by another
piece of energy shortly after, bringing the potential for
instability and rainfall (though under a tenth of an inch), and
suggesting a very small, but non- zero chance of thunderstorms as
early as Thursday (although non- monsoonal, tstms). However, as
with any low pressure system, the rainfall is highly dependent on
how far west the low tracks, and if it picks up enough moisture to
produce any storms.
&&
.AVIATION...05/2341Z.
At 2217Z at KLAX, the marine layer was 1100 feet deep. The top of
the inversion was 2200 feet with a temperature of 28 C.
High confidence in VFR TAFs for desert airfields (KPMD & KWJF).
Overall, moderate confidence for remaining TAFs. Least confident
in arrival of CIGs (+/- 3 hours). Good confidence in flight
categories. There is a 25% chance of no low clouds at KSBA and
KPRB. There is a 10% chance of that LIFR to IFR CIGs at KVNY &
KBUR between 08Z and 17Z.
KLAX...Moderate confidence in TAF. Arrival and departure times of
CIGs may be off by 2 hours. Flight cats could be off by one, but
high confidence in IFR/MVFR flight cats. No significant east wind
component expected.
KBUR...Moderate confidence in TAF. There is a 10% chance of LIFR
to IFR CIGs from 08Z to 16Z Sat.
&&
.MARINE...05/113 PM.
Small Craft Advisory (SCA) winds are expected through late tonight
for much of the outer waters. SCA level winds will become focused
across the waters south of Point Conception & far northeastern
portions of the northern outer waters on Saturday. Thereafter, SCA
level winds will be mainly focused south of Point Conception and
around the Channel Islands through Thursday. Also, there is a
moderate chance for SCA level winds across eastern portions of
the northern outer waters from Monday through Thursday. Relative
lulls will be possible each morning. There is a small chance of
Gales between Monday and Wednesday during the afternoon and
evening hours across the waters south of Point Conception. Seas
will remain below advisory levels.
Inside the southern California bight, SCA level wind gusts will
be possible across western portions of the Santa Barbara Channel,
near Point Dume, and across the San Pedro Channel each afternoon
and evening through Sunday. Elsewhere, winds and seas are expected
to remain below advisory levels. Chances notably increase next
week for SCA level winds across the SBA channel, potentially
impacting eastern portions. Seas will remain below SCA criteria
during this time, however may increase above 5 feet.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 9 PM PDT this evening
      for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Saturday for
      zones 670-673-676. (See LAXMWWLOX).
&&
$$
PUBLIC...Lund
AVIATION...Lewis
MARINE...Black
SYNOPSIS...MW
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox

NWS LOX Office Area Forecast Discussion