405
FXUS66 KLOX 110058
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
558 PM PDT Mon Aug 10 2026

.SYNOPSIS...10/534 PM.

A cooling trend will continue through Thursday, with cooler than
normal temperatures expected across the area into the weekend.
There is a chance of mountain and occasional lower elevation
convection through at least Wednesday night. More robust marine
layer cloud coverage is likely this week, however, higher clouds
may disrupt the formation of the marine layer at times.

&&

.SHORT TERM (TDY-THU)...10/206 PM.

After a long and persistent period of widespread above normal
temperatures, Southwest California is finally on the downward
trend temperature-wise. While today will remain seasonably warm
across much of the area, we`re expecting the gradual cooling trend
to result in below normal temperatures virtually everywhere by
Wednesday. The upper level ridge of high pressure responsible for
the above August-normal temperatures will finally be pushed east
while a weak trough moves down the West Coast by Wednesday and
sits along the coast of California for some time.

The threat of monsoonal convection will continue through at least
Wednesday as upper level flow remains south to southeasterly and
PWs sit around 1.5 inches at KLAX. Over the northern Ventura
County mountains as well as Eastern LA County mountains and
Antelope Valley, a 10-15% chance of showers/thunderstorms exists
this afternoon. Chances increase to 30-50% for similar areas plus
interior Santa Barbara County tomorrow and Wednesday. The upper
level trough along the coast will try to siphon in monsoonal
moisture on Wednesday, and this moisture combined with elevated
instability brings a 10-15% chance for thunderstorms in the
afternoon through late evening across much of SLO and Santa
Barbara Counties, highest in northwestern SLO County. While the
trough hangs out along the coast, there still exists a 5% chance
for convective storms to develop anywhere Thursday through Friday,
with lowering PW`s helping to keep any thunderstorms chances very
low.

Outside of potential convection, we can expect cooling each day
through Thursday thanks to the influence of this weak trough along
the coast. As the troughing pattern sets up, southwest flow aloft
will help aid in the slight increase in onshore flow, helping
bring cooler temperatures and more widespread marine layer cloud
coverage to the coasts coastal valleys this week. However, mid to
upper level clouds will try to inhibit the formation of marine
layer clouds. But with a fairly solid marine layer already in
place, we`re forecasting it to move into the coasts each day
through Thursday. We also expect it to deepen and reach most
coastal valleys by early Thursday morning. Regarding the increase
in onshore flow, wind advisories are not likely, but there is a
low to moderate chance for advisories to be issued for Wednesday
and Thursday across the Antelope Valley.

.LONG TERM (FRI-MON)...10/206 PM.

Weak upper level troughing will continue into the weekend.
However, 500 mb heights are expected to steadily climb Saturday
through Monday. The EC and GFS are in fairly good agreement that
500 mb heights will rise to around 590-592 dam by Sunday. Beyond
Sunday is where a significant disagreement occurs. Yesterday, the
EC favored another troughing pattern and the GFS favored the
ridging building back in. Today the two models have completely
flipped. There is even quite a range of outcomes starting Monday
within the EC Ensemble members. To say there is considerable
uncertainty for Monday and beyond would be an understatement.

What does seem likely is much lower chances of any sort of
convection as much of the monsoonal mositure moves back to the
south and east. However, there still remains a very low chance
(5%) for thunderstorms to develop virtually anywhere into the
weekend and the trough along the coastal will try to pull in some
remnant monsoonal mositure. Any sort of forcing from the trough
will attempt to create a build up. With generally limited
moisture, we would expect storm threats to generally be dry
lightning or gusty outflow winds rather than downpours.

Slightly increasing temperatures into the weekend also appear
likely. The good news for folks tired of the hotter than normal
temperatures is that current forecast high temps will still
remain below mid-August normals. One wrinkle is that onshore flow
is expected to steadily weaken into the weekend and the cooling
effects of nature`s air conditioning will decrease. The magnitude
of the decrease in onshore flow will certainly influence maximum
temperatures for this weekend into Monday.

&&

.AVIATION...11/0057Z.

At 2338Z at KLAX, the marine layer was 800 feet deep. The top of
the inversion was at 2400 feet with a temperature of 27 Celsius.

High confidence in TAFs for the valleys and deserts with VFR conds
expected. Lower confidence along the coast with LIFR to IFR conds
along the Central Coast, with a 30% chance that FG does not affect
KSMX. Further south, IFR conds at KSBA, KOXR and KCMA, but with a
chance of periodic or short duration CIGs occurring. IFR to MVFR
conds for the LA Coastal sites, where CIGs could also occur
periodically or for a short time.

There is a chance of -TSRA at KWJF KPMD through 03Z (10%) and on
Tuesday (30%). All other sites have a 5% chance of of -TSRA on
Tuesday.

KLAX...Low confidence in the 00Z TAF for the overnight period,
with bkn008-012 CIGs from 07Z to 17Z. There is a 40% chance that
CIGs do not occur, or they form and dissipate through that time
frame. There is also a 5% chance of -TSRA on Tuesday. High
confidence in minimal easterly winds.

KBUR...High confidence in VFR TAF with typical winds through
Tuesday. 5% chance of -TSRA Tuesday.

&&

.MARINE...10/152 PM.

High confidence that conditions will remain below Small Craft
Advisory (SCA) across all of the southwestern California coastal
waters through at least Friday night. Patches of dense fog are
possible on the Central Coast each morning. There is also a 5-10%
chance of a thunderstorm over the coastal waters Tuesday through
Wednesday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory in effect until midnight PDT Wednesday
      night for zones 349-350-354-362-366. (See LAXCFWLOX).
PZ...NONE.

&&

$$

PUBLIC...Lewis
AVIATION...Ciliberti
MARINE...RK
SYNOPSIS...Lewis

weather.gov/losangeles

Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox