Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 260332
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
832 PM PDT Mon Mar 25 2024

.SYNOPSIS...25/830 PM.

Weak high pressure will develop over the West Coast through
Wednesday which will bring warmer temperatures to the region.
Cooler temperatures are expected Thursday before a significant
storm moves into the region Friday through the weekend, possibly
bringing heavy precipitation and gusty winds.

&&

.SHORT TERM (MON-THU)...25/829 PM.

Drier northwest flow has developed over the area as the weekend
storm has moved into the Plains. The main short term issue will be
gusty northwest to north winds through tonight, reaching advisory
levels in the mountains and southern Santa Barbara county, with
gusts in the 35 to 50 mph range. Overall the winds are expected to
diminish in most areas on Tuesday as weak ridging develops over
the west coast. There will be the potential for more localized
wind advisory conditions on Tuesday night across southwest Santa
Barbara county and the I5 corridor.

Overall a very quiet period of weather through Thursday. Low
confidence with possible developing marine layer stratus Tuesday
or Wednesday morning across coast and valleys, however any low
clouds and fog should clear out by mid to late morning. Daytime
highs will warmer slightly each day through Wednesday, then
increasing onshore flow Thursday ahead of the next storm system
will result in cooling and increasing cloud coverage.

.LONG TERM (FRI-MON)...25/221 PM.

There is increasing confidence that a strong storm system will
generate significant impacts across our area by later this Friday
and continue through the weekend. Grand ensemble mean rainfall
amounts are still well over 1 inch for lower elevations and there
are at least 30% of the solutions that are over 3 inches. In fact,
the chances for those higher amounts are higher than the chances
for under 1 inch which is a very strong signal so many days out
that the models are trending stronger. Still, this is a dreaded
cut off low and the upper low center is expected to remain at
least 300 miles west of the coastline at least until Sunday. Even
a slight shift farther west over the ocean could result in a much
weaker system, but so far at least the ensembles have been
consistently favoring the stronger solution and given how the last
couple months have gone it`s certainly reasonable to err towards a
heavier system.

With that in mind, periods of heavy rain are expected to develop
by later Friday and continue into Saturday. Moderate southerly
flow will enhance rain rates and totals over the south and
southwest facing mountains generating at least twice if not three
times the rain amounts produced at lower elevations. Snow levels
expected to hold around 6000 feet through Saturday, but above that
level there could be snow accumulations in excess of 2 feet, and
at even elevations above 7500 feet as much as 3-4 feet.

Steady precipitation is expected to turn to more showery and
possibly convective Sunday into Monday. Although most of the
model solutions show the upper low moving onshore over northern
Baja, cyclonic circulation aloft along with a higher sun angle
creating better surface heating could be a recipe for strong
thunderstorms and possible waterspouts and even small tornados.

Also, given the state of our hillsides after the heavy rain
earlier this season it`s very likely that this storm will create
many additional mud and rock slides in the hills and mountains so
residents in those areas are urged to take any precautions as soon
as possible.

&&

.AVIATION...25/1842Z.

At 18Z at KLAX, there was no marine layer nor a marine inversion.

Low to moderate confidence in forecast between 06-18Z for KSMX
and north (40-60 percent of low MVFR/IFR cigs/vsbys) and KLAX,
KSMO, and KLGB (20-40 percent of low MVFR/IFR cigs/vsbys) due to
uncertainty in low cigs/vsbys. There is a less than 10 percent
chance for KBUR. Otherwise and elsewhere high confidence in VFR
conditions prevailing.

KLAX...Moderate confidence in TAF. There is a 20-30 percent
chance of MVFR cigs from 09Z-17Z. There is less than a 10 percent
chance of brief east component to 8 kts between 12-17Z.

KBUR...High confidence in TAF. There is a 10-20 percent chance of
SW winds from 230-240 at 12-15 kt from 20Z-00Z. There is less
than a 10 percent chance of low MVFR to IFR cigs after 10Z
tonight.

&&

.MARINE...25/111 PM.

In the outer waters, Gale Force winds will continue in the
southern zones (PZZ673/676) thru late tonight, with Small Craft
Advisory (SCA) level winds/seas to follow thru Tue night. In the
northern zone (PZZ670), SCA conds are expected thru Tue evening,
with a lull in winds and seas late tonight/Tue morning. SCA conds
are not expected in the outer waters Wed thru early Thu, then are
likely Thu afternoon into Thu night, with SCA level seas into Fri.

In the inner waters N of Pt. Sal, SCA level winds/seas are expected
thru tonight. There is a 30% chance of seas at SCA levels into Tue
morning. There is a 40% chance of SCA level winds Tue afternoon/eve,
and Thu afternoon/eve, with SCA level seas Fri.

In the SBA Channel and southern inner waters, SCA level winds are
expected thru tonight across the western portions, and this
afternoon/eve elsewhere. There is a 20% percent chance of brief
Gales between Malibu/Point Mugu and the Channel Islands late this
afternoon or early evening. SCA level winds and seas are likely
Tue afternoon/eve, and again Thu afternoon/eve.

Dangerous, large and rough seas across the entire waters will
slowly subside beginning later today, but will remain near SCA
levels across the outer waters into Tue night.

A late season significant storm is possible this weekend,
potentially bringing at least SCA west to south winds, large seas,
and a 10 percent chance of thunderstorms.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 3 AM PDT Tuesday for zones
      349-351. (See LAXNPWLOX).
     Wind Advisory in effect until 9 AM PDT Tuesday for zones
      350-352-353-376>378. (See LAXNPWLOX).
     Wind Advisory in effect until 10 PM PDT this evening for
      zones 381-383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 AM PDT Tuesday for
      zones 645-650-655-670. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Tuesday for zones
      673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Gomberg/Wofford
AVIATION...Munroe
MARINE...Munroe/DB
SYNOPSIS...MW

weather.gov/losangeles

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


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