Glassell, California Weather Forecast Discussion

355
FXUS66 KLOX 091020
AFDLOX
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
320 AM PDT Tue Sep 9 2025
.SYNOPSIS...08/724 PM.
A significant cooling trend will continue through Thursday as a
low pressure system approaches northern California. This will
result in much cooler temperatures across Southwest California.
In addition, marine layer clouds will expand across coastal areas
and well inland over the valleys with morning drizzle possible
through Friday. A small warming trend is then expected Friday into
the weekend.
&&
.SHORT TERM (TDY-THU)...09/235 AM.
A large and unseasonably cool (569 dam) upper low will move into
NRN CA today and will persist over the area through early Thursday
before slowly pushing to the east. The upper low will bring
increasing cyclonic flow and lowering hgts to Srn CA. Hgts this
morning are near 586 dam and will fall to 578 dam by Thursday.
Moderate onshore flow to the east will continue through the
period. In the N/S direction there will be weak offshore flow in
the morning and moderate onshore flow in the afternoon.
There is no eddy this morning and as a result there is not much
marine layer stratus across the LA cst. Moist westerly flow has
brought low clouds into the VTA county coast. Marine layer clouds
are much better established in across the Central Coast and the
Paso Robles area. The increasing cyclonic flow tonight will bring
a hefty amount of lift and low clouds should penetrate deep into
the vlys. The lift will be strong enough to bring areas of drizzle
to much of the coasts and vlys as well. The low cloud pattern will
be similar on Thursday morning, but there will be much less lift
and the threat of drizzle will be much reduced.
The deeper marine layer and lowering hgts will combine to bring
two days of cooling to almost all areas. Look for 3 to 6 locally 8
degrees of cooling today and then an additional 2 to 4 degrees on
Wednesday. There will be slightly less cooling across the near
shore area. Thursday`s temps will change little from Wednesday`s
values. Max temps across the vlys on Wed/Thu will be 6 to 12
degrees blo normal.
The gusty winds aloft assoc with the trof and a moderate onshore
push to the east will bring low end advisory level wind gusts to
interior passes and canyons of the San Gabriel Mountains and the
Antelope Valley Foothills through this evening.
.LONG TERM (FRI-MON)...09/303 AM.
The trof will continue to slide to the east on Friday and will be
replaced by a weak ridge which will raise hgts to about 585 dam
and persist into Saturday. The increase in hgts will smoosh the
marine layer some and this will limit the vly penetration south of
Pt Conception. Weak offshore flow across the Santa Ynez range will
also keep most of the SBA south coast clear as well. Moderate
onshore flow into the Central Coast will keep a robust stratus
layer across the area as well as the Santa Ynez Vly. The ridge as
well as a faster clearing marine cloud layer will allow for 2 to 3
degrees of warming each day. Despite this warming max temps will
remain 3 to 6 degrees blo normal across the coasts and 5 to 10
degrees across the vlys.
The ridge is short lived and will be replaced by a weak trof for
Sun and Mon. Hgts and pressure gradients really do not change much
at all and there will actually not be much change in the night
through morning cloud pattern or the temperatures.
&&
.AVIATION...09/1018Z.
Around 0430Z at KLAX, the marine layer depth was around 800 feet
deep. The top of the marine inversion was near 1800 feet with a
temperature around 23 degrees Celsius.
High confidence exists in the current forecast for desert
terminals. Low-to-moderate confidence exists in the current
forecast for coastal and valley terminals.
IFR to MVFR conditions will develop at most coastal and valley
terminals through 15Z. There is a low-to-moderate chance of VFR
conditions persisting at Los Angeles County coastal and valley
terminals through tonight. There is a small chance of IFR
conditions in drizzle or light rain through 17Z. There is a better
chance of low clouds with IFR to MVFR conditions tonight at
terminals south of Point Conception.
KLAX...IFR to MVFR conditions could spread into KLAX as soon as
12Z. There is a 10 percent chance of VFR conditions persisting
through at least 06Z Wednesday. VFR conditions should develop by
18Z at the latest. A return of IFR to MVFR conditions could occur
as soon as 01Z Wednesday or as late as 08Z Wednesday. There is a
30 percent chance of IFR conditions in drizzle this morning and
after 08Z Wednesday. There is a 30 percent chance of east winds
between 7 and 10 knots between 14Z and 17Z.
KBUR...There is a 40 percent of no low clouds at KBUR. VFR
conditions should develop by 16Z at the latest. IFR to MVFR
conditions could arrive as soon as 05Z or as late as 10Z.
&&
.MARINE...09/318 AM.
For the waters west through northwest of Point Sal including the
nearshore waters along the Central Coast, winds and seas should
remain below Small Craft Advisory (SCA) levels through early
Wednesday, but there is a moderate-to-high (30-50 percent) chance
of SCA level winds on Tuesday afternoon and evening. By Wednesday
evening, there is a high-to-likely (50-70 percent) chance of SCA
level northwest winds developing and lingering into at least
Sunday. Brief lulls in the winds are possible at times during the
late night and early morning hours.
For the waters south through west of the Point Sal and outside the
southern California bight, there is a likely (60-80 percent) chance
of SCA level northwest winds through at least Sunday. The highest
chance of SCA level winds will occur between Wednesday evening
and Friday morning from around Point Conception south to San
Nicolas Island.
Inside the southern California bight, there is a high-to-likely
(50-70 percent) chance of SCA level west winds each afternoon and
evening through Wednesday night, highest across the Santa Barbara
Channel, near Point Dume, and across the San Pedro Channel. There
is a high (40-50 percent) chance of hazardous short period seas
developing this evening across the Santa Barbara Channel. There
will likely be brief lulls in the winds during the morning hours
each day. For late week, there is a moderate-to-high (30-50
percent) chance each afternoon and evening through the remainder
of the week.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory remains in effect until 5 AM PDT early this
      morning for zones 349-351. (See LAXNPWLOX).
     Wind Advisory remains in effect from 10 AM this morning to 9
      PM PDT this evening for zones 379>382. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Wednesday for
      zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 9
      PM PDT this evening for zone 655. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Thursday for
      zones 673-676. (See LAXMWWLOX).
&&
$$
PUBLIC...Rorke
AVIATION...Hall
MARINE...Hall
SYNOPSIS...CC/KL
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox

NWS LOX Office Area Forecast Discussion