603
FXUS66 KLOX 311258
AFDLOX
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
558 AM PDT Mon Mar 31 2025
.SYNOPSIS...31/351 AM.
It will be mostly cloudy and cool today. There will be occasional
light rain this morning and a slight chance of showers this
afternoon, possibly lingering on northern slopes tonight. The
southern end of a frontal system may bring light rain to northern
and mountain areas Tuesday into Tuesday night. Otherwise, it will
be partly cloudy and dry Tuesday through Wednesday with areas of
gusty winds. There is a slight chance of light rain Thursday
afternoon and evening, then dry weather is expected Friday through
the weekend, with a warming trend.
&&
.SHORT TERM (TDY-WED)...31/442 AM.
Skies were cloudy across the forecast area this morning, with
areas of light rain. A very weak trough was located just off the
West Coast, with broad weakly cyclonic flow through a deep moist
layer over the forecast area. A vort max moving toward the region
will cause the low and mid level flow to back slightly early this
morning, and will result in some improved low level lift. This may
help to increase rainfall coverage somewhat for a few hours early
this morning, but it now appears that the best lift will remain
just south of the region today. Still, areas of light rain are
likely through mid or possibly late morning, with a chance or
slight chance of showers lingering this afternoon. Additional
rainfall totals should be one quarter of an inch or less, with
locally higher totals possible in the foothills and mountains.
There may be some sunshine this afternoon, but overall it should
be a rather cloudy day. It will be quite cool today, with max
temps in the mid 50s to mid 60s west of the mountains, which is
about 6 to 12 degrees or so below normal for the end of March. It
will be quite windy across the interior, especially in the
Antelope Valley and adjacent foothills, where Wind Advisories are
in effect.
Low level flow will turn more northwesterly to northerly across
the region tonight. Upslope flow interacting with abundant
residual low level moisture will keep at least a slight chance of
showers on the northern mtns slopes tonight. Snow levels which
have been rather high will begin to lower tonight, with snow
possibly falling as low as 5000 feet by late tonight. This should
be above most major roadways through the mountains, and amounts
should be rather light anyway. Gusty NW winds will affect the
Santa Ynez Range and adjacent south coast of SBA County, and the
Interstate 5 Corridor tonight, but at this point, winds are
expected to remain below advisory levels there.
A fairly strong and cold upper low will move into the Pacific
northwest very late tonight and Tue with a broad trough extending
southward into the forecast area. The southern end of its
associated surface front may bring some light rain (with snow
above 5000 feet) to SLO County and most of SBA County, and to the
mountains of Ventura County Tue, lingering into Tue evening, with
the chance of showers spreading into the mtns of L.A. County.
Otherwise, skies will be partly cloudy Tuesday, and it will still
be quite cool, with max temps similar to those today. Gusty west
winds will affect coastal areas and some valley areas Tue
afternoon and evening, likely reaching advisory levels.
The upper low moving into the Pac NW Tue will drop south
southeastward into Nevada and southeastern CA Tue night and
Wed morning. Upper level flow will turn northerly and increase Tue
night, and low level winds will turn also turn northwesterly.
Advisory level NW winds are likely in the Interstate 5 Cooridor,
the mountains of VTU County, and possibly portions of southern
SBA County. Moist upslope northerly flow will keep a slight chance
of rain showers and snow showers across the mtns of northern VTU
County and NW L.A. County Tue night/early Wed.
The upper low will move eastward across northern Arizona Wed,
with weakly cyclonic NW flow aloft over the region. Wed will be
partly cloudy and cool, and there will be areas of gusty west to
northwest winds, possibly reaching advisory levels in some areas.
It will remain quite cool across the area Wed, with temps again
likely failing to reach 70 degrees anywhere in the forecast area.
.LONG TERM (THU-SUN)...31/557 AM.
The GFS and EC are in fairly good agreement with the upper level
pattern in the long range portion of the forecast. A short wave
will drop southward through the Pac NW and into the western Great
Basin Thu, evolving into a closed upper low over the lower Colorado
River Valley late Thu/Thu night. This system will be very starved
for moisture, but there is a slight chance of showers Thu
afternoon, especially in L.A./VTU Counties, lingering in the
mountains into the evening. Thu will be another chilly day, with
max temps again below 70 degrees everywhere in the forecast area.
The upper low will continue to drop southeastward into northern
Mexico Fri. Heights will begin to rise, and increasing N-S
gradients will bring gusty winds to portions of the region. There
will be drying through the atmosphere, so expect mostly clear
skies. Max temps will be up several degrees in most areas Fri,
with highs rising into the 70s in some valleys and across interior
sections of the coastal plain, close to normal for early April.
An upper ridge will amplify just off the West Coast over the
weekend, causing heights to rise. Low level N-S gradients will be
offshore, and W-E gradients between KLAX and KDAG will turn
weakly offshore as well. It will most likely be dry and warmer
over the weekend, with max temps possibly rising into the lower
80s in the warmest locations in the valleys and across interior
sections of the coastal plain. However, decent short wave energy
will drop southward through the Great Basin Sat. This will form an
upper over southern Nevada late Sat, which will track into
Arizona Sun. If that system digs a bit farther to the west, across
eastern CA, max temps would be lower than currently forecast.
&&
.AVIATION...31/1204Z.
At 1007Z at KLAX, there was no marine layer nor a sfc-based
inversion.
Overall, low to moderate confidence in 12Z TAF Package. Timing of
cig/vsby restrictions may be off +/- 2 hours. Flight cats could
be off one or two thru 00Z Tue. -SHRA chances at times. Gusty W to
SW winds will affect the Antelope Valley thru the fcst pd. Light
LLWS and turbulence possible at times over the Antelope Valley,
San Gabriel + Topatopa mtns.
KLAX...Low to moderate confidence in the 12Z TAF. Cigs and vsbys
will fluctuate significantly at times thru 00Z Tue - Generally
ranging anywhere from LIFR to MVFR conds. -SHRA chances thru
around 21Z Mon. East wind component around 10 kts expected thru
~18Z Mon (+/- 1 hour).
KBUR...Low to moderate confidence in the 12Z TAF. Cigs and vsbys
will fluctuate significantly at times thru 00Z Tue - Generally
ranging anywhere from LIFR to MVFR conds. -SHRA chances thru
around 19Z Mon.
&&
.MARINE...31/212 AM.
For the Outer Waters, moderate to high confidence in the
forecast. There is a 30-50% chance of SCA level W wind Mon, with
SCA level NW winds and seas likely (80% chance) Tue thru Thu
night. There is a 50-60% chance of GALE force wind gusts,
especially south of Pt Conception, Tue afternoon thru Wed morning,
decreasing to 30% chc thru Wed night. Issued a Gale Watch for Tue
afternoon thru Wed mid-morning for PZZ650/655/676.
For the Inner Waters N of Pt. Sal, moderate to high confidence in
the forecast. SCA conds are not expected Mon thru early Tue
morning. SCA level NW winds are likely during the afternoon/eve
hours Tue thru Thu, and seas are expected to be near or above SCA
levels except for Thu as it subsides.
For the Inner Waters S of Pt. Conception, moderate confidence in
the forecast. There is a 80% chc of SCA winds Mon afternoon/eve
for SBA Channel, and beginning in the evening hours for PZZ655.
SCA winds are expected to persist until it increases to GALE force
wind gusts Tuesday afternoon thru Wed mid-morning (50-60% chc). A
GALE watch has been issued for this timeframe. Seas may also
reach SCA levels Tue afternoon through Wed afternoon, with up to
11 feet possible across the San Pedro Channel.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 2 AM PDT Wednesday for zones
381>383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 3 PM this afternoon to 3
PM PDT Tuesday for zone 650. (See LAXMWWLOX).
Gale Watch in effect from Tuesday afternoon through Wednesday
morning for zones 650-655-676. (See LAXMWWLOX).
Small Craft Advisory in effect from 9 PM this evening to 3 PM
PDT Tuesday for zones 655-676. (See LAXMWWLOX).
&&
$$
PUBLIC...DB
AVIATION...Black
MARINE...Black/Smith
SYNOPSIS...DB
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=lox
NWS LOX Office Area Forecast Discussion
