215
FXUS66 KLOX 111720
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1020 AM PDT Fri Sep 11 2026

UPDATED AVIATION SECTION

.SYNOPSIS...11/243 AM.

A cooling trend will affect the region through the weekend with
max temps dropping to below normal by Sunday. The sticky tropical
air will finally exit the region by this weekend. Marine layer
clouds will likely return to many coastal areas.

&&

.SHORT TERM (TDY-SUN)...11/814 AM.

***UPDATE***

Heat advisories will continue through this evening for coastal
areas from Santa Barbara south through Los Angeles due to moderate
risk of heat illness from still warm morning temperatures and
highs running up to 10 degrees above seasonal normals. Some
inland areas are on the fringe of heat advisories due to warm
morning temps, but we will leave them since max temps in those
areas will run only around 5 degrees above normal.

Otherwise the cooling trend today will start the first over the
next few days or so, with very quiet weather on the horizon.
Additionally humidities will continue to lower through today, but
even more so into Saturday.

The one exception to the quiet weather is the potential for
advisory level Sundowner winds tonight through the weekend,
likely peaking Saturday or Sunday. A wind advisory has been issued
for tonight across the Santa Barbara southwest coast.

We finally saw a return of some marine layer stratus this
morning, with some patchy stuff south of Point Conception and a
little more solid along the Central Coast. Expecting better
coverage tonight.

***From Previous Discussion***

The ridge that brought the very high hgts will flatten out and
hgts will fall to a about 588 dam. At the sfc there will be weak
to moderate onshore flow in the E/W direction. The N/S gradients
will feature weak offshore flow in the mornings and weak onshore
flow in the afternoons.

This will kick off a three day cooling trend with most max temps
falling 4 to 8 degrees today, 3 to 6 degrees Saturday and 2 to 4
degrees Sunday. By Sunday Max temps will mostly be in the upper
70s to 80s across all of the csts/vlys or 3 to 6 degrees blo
normal.

The marine cloud layer is advancing down the coast and there are
signs of an eddy. Marine layer stratus will slowly increase in
coverage through the period, although the very warm sea sfc temps
will have an inhibiting effect.

The real good news is the the humidities will fall back to normal.
PWs over srn LA county ydy were near 1.70" and will fall to 1.3"
today and then to .85" Saturday.

The decrease in available mositure will eliminate the threat of
afternoon convection.

Not much in the way of winds through the short term. Just the
typical gusty west afternoon winds in the Antelope Vly and the
evening Sundowners west of Isla Vista on the SBA south coast.

.LONG TERM (MON-THU)...11/928 AM.

Not much change through Wednesday, with zonal flow continuing at
the upper levels. Temperatures will remain below seasonal
normals. Weak to moderate onshore flow will continue with light
northerly offshore flow each night through morning. There will
likely be some morning low clouds each day with the greatest
coverage across the Central Coast. Skies, otherwise, will be
mostly clear.

A good degree of mdl confusion creeps into the forecast later
Wednesday into Thursday as the mdls struggle with the handling of
some energy coming out of British Columbia. The sfc pattern is
also in question as there is wide assortment of possible values
ranging from 1mb onshore to 6.5 mb onshore. While the actual
outcome regarding how much warmer it will be and how quickly
things warm up is still uncertain, ensembles do suggest a slight
warming trend Thursday and Friday. So confidence in at least some
warming is growing, with the details remaining in question. A
majority of the European ensemble members also increase PWATs to
over an inch as early as Thursday, so there is also potential for
increased mugginess once again. The good news is most members are
keeping PWATs below 1.5, much lower than the peak of the extreme
heat and humidity this past week.

No significant wind issues are expected, although there will be
the usual gusty southwesterly winds each afternoon across the
mountains and deserts and the typical near advisory level evening
gusts across the SW corner of SBA county.

&&

.AVIATION...11/1718Z.

At 1622Z at KLAX, the marine layer was 1700 ft deep. The top of
the inversion was at 2600 ft with a temperature of 25 C.

High confidence in VFR TAFs for desert airfields (KPMD & KWJF).

Moderate confidence in VFR conditions for KPRB (10% chc of brief
LIFR CIGs 12/12Z-15Z), KVNY (15% chc of LIFR/IFR CIGs 10Z-15Z).

For remaining TAFs, low to moderate confidence. Timing of
CIG/VSBY restrictions may be off +/- 3 hours & flight minimums
by one category.

KLAX...Moderate confidence in TAF. Arrival and clearing of IFR
to MVFR Cigs (008-012) may be off +/- 2 hours. No significant
east wind component expected.

KBUR...Moderate confidence in TAF. 15% chc of LIFR/IFR CIGs
12/10Z-15Z. No wind issues expected.

&&

.MARINE...11/819 AM.

Conditions are expected to become increasingly hazardous across
the outer waters into the weekend. A Gale Watch (50-60% chc) has
been issued for PZZ676/673 Saturday evening into Monday morning.
The coastal Jet may develop across PZZ670 Saturday evening causing
winds to increase there as well, but confidence in winds reaching
Gale force is low at this time. Otherwise, widespread SCA winds
are expected across the outer waters through early next week.
Small Craft Advisory (SCA) conditions are expected to reach into
the nearshore waters along the Central Coast and the Santa Barbara
Channel at times (especially during afternoon/eve hours) through
early next week.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory in effect until 6 PM PDT this evening for zones
      349-350-354-355-362-366>368. (See LAXNPWLOX).
     Wind Advisory in effect from 6 PM this evening to 3 AM PDT
      Saturday for zones 349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 2 PM this afternoon to 9
      PM PDT this evening for zone 645. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 PM this afternoon to 3
      AM PDT Saturday for zone 650. (See LAXMWWLOX).
     Small Craft Advisory in effect until 9 AM PDT Monday for zone
      670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 6 PM PDT Saturday for
      zones 673-676. (See LAXMWWLOX).
     Gale Watch in effect from Saturday evening through Monday
      morning for zones 673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Lewis/Rorke
AVIATION...Black
MARINE...Black/Ciliberti
SYNOPSIS...Lewis/Ciliberti

weather.gov/losangeles

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

NWS Los Angeles (LOX) Office