939
FXUS66 KLOX 150529
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1029 PM PDT Sat Mar 14 2026

.SYNOPSIS...14/736 PM.

A significant heat wave will kick off on Sunday, peak next
Tuesday and Wednesday, and then continue through Friday. MODERATE
to HIGH heat impacts will occur each day Monday through Friday.

&&

.SHORT TERM (SAT-TUE)...14/823 PM.

***UPDATE***

Good cooling occurred across the area today, with most locations
seeing high temperatures around 5 to 10 degrees cooler than
Friday. Valley highs dropped from the lower to mid 90s on Friday
to the 80s today, with similar trends in coastal areas of Ventura
and LA Counties. Along the Central Coast, temperatures lowered
around 2 to 6 degrees, with some locations in Central San Luis
Obispo County showing little change. Gusty northerly winds are
affecting isolated areas, mainly over SW Santa Barbara County and
in the I-5 Corridor, with mainly sub-advisory gusts.

For the overnight period, broken low clouds with patchy dense fog
will affect portions of the LA Coast, with a small chance that
the clouds will spread north to the Ventura Coast. Northerly winds
will continue over the interior of Ventura and LA Counties, with
northeast flow developing for the interior of the counties north
of Pt. Conception.

Sunday will be the first day of an extended heat wave, with highs
increasing anywhere from 3 to 12 degrees warmer in most locations.
Much more significant warming is expected to begin on Tuesday
under strongly increasing high pressure aloft combined with
offshore flow at the surface.

***From Previous Discussion***

Forecast-wise for the short term, main story remains a historic
heat event for the area. With the ridge building overhead and the
increase in offshore gradients, temperatures will be on a
dramatic upswing through the period. On Sunday, temperatures will
climb into the 80s to lower 90s for most areas with the beaches in
the mid to upper 70s. On Monday, temperatures will climb into the
mid 80s to upper 90s then into upper 80s to 104 on Tuesday. At
the same time, overnight lows will also exhibit a warming trend,
especially across the coastal foothills. Depending on the strength
of the offshore flow, temperatures on Monday and Tuesday could
even be little bit warmer than currently forecast for areas west
of the mountains. Given the associated heat risk, have decided to
issue a HEAT ADVISORY on Monday for all coastal and coastal
valley zones as well as the mountains. For Tuesday, have left
these same areas as an EXTREME HEAT WATCH, but this will likely be
upgraded tomorrow to warnings.

Other than the temperatures, no significant issues are expected.
There will be some gusty northerly winds through tonight across
the usual areas (I-5 Corridor and Santa Ynez Range), but any
advisory-level winds are expected to remain localized. For Monday
and Tuesday, the offshore gradients in the morning will generate
some gusty northeasterly winds, but again, any advisory-level
gusts are expected to remain localized.

As for clouds, other than some stratus/fog across the Bight and
the LA county coast tonight/Sunday morning, skies should remain
mostly clear through Tuesday.

.LONG TERM (WED-SAT)...14/1251 PM.

Overall, 12Z models remain in good synoptic agreement through the
period. At upper levels, the high will slowly meander to the
southeast through the period. Near the surface, models continue
the trend of previous runs, the GFS forecasts weak diurnal
gradients while the ECMWF has weak offshore gradients through the
entire period.

Forecast-wise, nothing in the latest model guidance deviates from
the expectation of a historic, long-duration, heat event for the
area. The only uncertainty remains around the surface pressure
gradients. If the ECMWF is correct with the persistent weak
offshore flow, then temperatures will even be warmer than the
currently forecast temperatures (which have many areas breaking
daily and even monthly records). Essentially, just how extreme
will the extreme heat be is the major question. For the forecast,
have continued toeing the line between the NBMEXP and the 75th
percentile NBM numbers both for the maximum and minimum
temperatures. So with the afternoon forecast, will keep EXTREME
HEAT WATCHES in effect through Friday for all coastal and coastal
valley zones as well as the mountains. Most likely, these will be
upgraded tomorrow.

Given the unprecedented length and magnitude of this extreme heat
wave, heat stress will be a real threat each day, especially in
areas that aren`t used to the heat, like the coastal areas, where
people may not have methods to cool off their homes. Try to
complete outdoor activities early in the day or in the evening,
and don`t leave people or pets in cars.

As for any rain chances, latest deterministic and ensembles have
changed tunes slightly, indicating some low chances of light
showers after the 25th. However, models do not indicate any
significant storms.

&&

.AVIATION...15/0528Z.

At 0445Z at KLAX, there was no marine layer. There was a surfaced
based inversion with a top at 1600 ft and a temperature of 21 C.

Low to moderate confidence in TAFs south of Point Conception.
Timing of CIG/VSBY restrictions may be off +/- 3 hours and
flight minimums by one category. There is a 40% chance that LIFR
CIGs arrive at KSBA from 15/11Z-16Z.

Chances CIGs do NOT arrive: KOXR (30%), KCMA (5O%).

KLAX...Moderate confidence in TAF. Generally expecting: OVC002-006
with 2-4SM Vsbys. 30% chance conditions fall to VLIFR thru 15/12Z.
Clearing times of CIGs may be off by +/- 2 hours. 50% chance LIFR
CIGs return after 16/06Z. Good confidence that any east wind
component will be below 7 kts.

KBUR...High confidence in VFR TAF.

&&

.MARINE...14/755 PM.

Small Craft Advisory (SCA) level NW-N winds of 20-30 kt will
continue across the Outer Waters through Sunday night. Gusts will
reach GALE FORCE (35 kt) through tonight especially beyond 30 NM
from Shore. Short- period seas will also peak near 10 ft across
these waters through tonight. Conditions are likely to improve
early next week, with relatively small seas expected.

SCA level NW winds will affect the Inner Waters along the Central
Coast especially during the afternoon and evening hours today,
with localized SCA wind gusts lingering into Sunday. Otherwise,
conds will likely remain below advisory levels through Thursday.

Inside the Southern California Bight, conditions are expected to
remain below SCA levels for the foreseeable future, except for
marginal SCA winds this afternoon and evening focused across the
western portion of the Santa Barbara Channel.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory remains in effect from 10 AM to 8 PM PDT Monday
      for zones 87-88-340>342-345>358-362-366>376-378>380-548. (See LAXNPWLOX).
     Extreme Heat Watch in effect from Monday evening through
      Friday evening for zones
      87-88-340>342-345>358-362-366>376-378>380-548>550. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Sunday for zone
      645. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Sunday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Thompson
AVIATION...Black
MARINE...Black/RS/KL
SYNOPSIS...RAT/CC

weather.gov/losangeles

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

NWS Los Angeles (LOX) Office