550
FXUS66 KLOX 241226
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
526 AM PDT Sun Aug 24 2025

.SYNOPSIS...23/811 PM.

High pressure over the Four Corners Region will persist through
at least Sunday, keeping a very warm air mass over the region.
Monsoonal moisture moving over the area will cause continued
humid conditions, along with possible showers and thunderstorms
over the mountains and desert in the afternoon to evening hours
through Tuesday. A cooling trend is expected for next week as a
weak upper- level trough approaches the West Coast.

&&

.SHORT TERM (TDY-TUE)...24/332 AM.

A 593 dam upper high continues to sit atop of the 4 corners
region. At the sfc there will be weak onshore flow both to the
east and west. Temperatures will be similar to ydy save for the
Antelope Vly where less cloud cover is forecast and temps are
forecast to rise by 3 to 6 degrees. The monsoon has pumped up
humidities across the area. In addition to making the daytime
temperatures feel worse the added moisture is also hindering the
overnight cooling. The combination of warm overnight lows,
humidity and above normal temperatures will create one more day of
dangerous heat conditions and heat warnings and advisories are in
effect through this evening.

The monsoon flow will also continue the threat of showers and
TSTMs. There is a little more moisture at the lower levels this
afternoon, so any TSTM that develops could produce more rainfall
than those ydy. The steering flow is also weak so there is risk
of flash flooding this afternoon. Some of the TSTMs will be high
based and will continue the threat of dry lightning. In addition,
there will still be the threat of strong/erratic wind gusts up to
50 mph under and near to any TSTM that develops.

The high pretty much collapses on Monday and a weak upper low sets
up over the northern 2/3rds of the state. Some coastal low clouds
will develop as well. Hgts will fall to 588 dam. Max temps will
drop 3 to 6 degrees. This cooling will be enough to end the heat
issues. Enough residual moisture will remain over the mtns to
warrant a slight chc of TSTM for the LA/VTA mtns and the AV.

More marine layer and better onshore flow along with the upper
low`s influence will knock another 2 to 3 degrees off of the
temps on Tuesday. This cooling will bring max temps down to near
normal. Mdls still show just enough moisture for a slight chc of a
shower of TSTM in the afternoon over the LA/VTA mtns and the AV.

.LONG TERM (WED-SAT)...24/342 AM.

Mdls are in decent agreement that an upper low will approach the
PACNW and then sweep into British Columbia. This will bring dry SW
flow into Srn CA which will eliminate the monsoon threat. Onshore
flow increases to moderate levels and along with troffing aloft
will work to bring night through morning low clouds to most of the
coasts and some of the lower vlys. Most max temps will slowly
cool through Friday when vly highs will only be in the mid 80s to
lower 90s or 4 or 5 degrees under normal. A few degrees of warming
is forecast for Saturday although given the pattern this may be
optimistic.

Looking further out to the rest of the Holiday weekend there does
not look like any meaningful weather with a warming likely both
days Sun and Mon.

&&

.AVIATION...24/1226Z.

At 0653Z at KLAX, the marine layer was 1000 ft deep. The top of
the inversion was 2000 feet with a temperature of 29 C.

Good confidence in all TAFs xcp for KSMO, KLAX and KLGB where
there is a 30 percent chc of IFR cigs until 16Z, with any cigs
that do form likely to scatter and reform. Low confidence in any
flight category restrictions tonight, especially for coastal sites
south of Point Conception.

There is a 30 percent chc of TSTMs over LA county 14Z-02Z mainly
over the mtns.

KLAX...Moderate confidence in TAF. There is a 30 percent chc of
OVC005 conds until 16Z. There is a 10 percent chc of a shower or
TSTM 14Z-02Z. Good confidence that any east wind component will be
under 5 kt.

KBUR...High confidence in TAF. There is a 15 percent chc of a
shower or TSTM 14Z-02Z.

&&

.MARINE...24/235 AM.

For the Outer Waters, high confidence in Small Craft Advisory
(SCA) level winds through at least late tonight. For Monday
through Thursday, there is a 40-60% chance of SCA level winds,
mainly around Point Conception during the afternoons and evenings.

For the western half of the Santa Barbara Channel, there is a
20-30% chance of SCA level winds through Thursday during the late
afternoon and evening hours. Otherwise, high confidence in winds
and seas remaining below SCA levels through Thursday for the
remainder of the Inner Waters.

Dense fog with visibilities of one nautical mile or less will be
possible this weekend during the night and morning hours,
especially off the Central Coast.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Extreme Heat Warning in effect until 9 PM PDT this evening
      for zones 38-88-342>345-348-351>353-368>383-548. (See LAXNPWLOX).
     Heat Advisory remains in effect until 9 PM PDT this evening
      for zones 356>358. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Monday for
      zones 670-673. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Monday for zone 676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...Rorke/Schoenfeld
MARINE...Ciliberti/Schoenfeld
SYNOPSIS...Hall/Ciliberti

weather.gov/losangeles

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