556
FXUS66 KLOX 071125
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
425 AM PDT Tue May 7 2024

.SYNOPSIS...06/234 PM.

Dry conditions, warming temperatures, and areas of breezy north
to northwest winds are expected this week into the weekend. Low
clouds and perhaps patchy fog could return to coastal areas by the
end of this week and the upcoming weekend.

&&

.SHORT TERM (TDY-THU)...07/424 AM.

Except for patchy low clouds and fog across the southern Central
Coast and Santa Ynez Valley, and portions of interior SLO County,
skies were clear across the region. Any low clouds should
dissipate by mid morning. Otherwise, today will be a mostly sunny
day, with just some high clouds from time to time. Broad weakly
cyclonic northwesterly flow aloft will continue across the region
today. Heights will actually drop a bit today as a vort drop south
trough the Great Basin. The WRF shows a bit of cooling at 950 mb.
Overall, changes are minimal, so do not expect too much change in
max temps from those on Mon.

Gusty north winds continued across the Interstate-5 Corridor and
the northern Ventura County mountains early this morning, and a
Wind Advisory remained in effect thru mid morning, which looks
fine, since winds will be diminishing. However, N-S gradients,
winds aloft, and subsidence, support another round of gusty
northwest to north winds late this afternoon or early this evening
through late tonight. Winds should reach advisory levels late
this afternoon across southwestern SBA County, through the I-5
Corridor, in the western foothills of the Antelope Valley, and in
far western portions of the Antelope Valley itself. During the
early evening hours. advisory level winds should also develop in
the mountains of Ventura County, the interior mountains of SBA
County, southeastern SBA County, and the Santa Clarita Valley.
This is already nicely accounted for in the current batch of wind
advisories, with the only addition being the far western portion
of the Antelope Valley.

The low level flow should turn northeasterly late tonight and Wed
morning. This should bring an end to advisory level winds in most
area by late tonight. For late tonight and Wed morning, some gusty
NE winds are possible in the mtns of L.A. and eastern Ventura
County, and locally in the valleys, but expect the northeast
winds to remain below advisory levels. The WRF shows some stratus
moving into coastal areas of L.A. County and portions of the
southern Central Coast and Santa Ynez Valley late tonight and Wed
morning, but with weak offshore flow developing, any low clouds
should be gone quickly Wed morning. Heights across the region will
be lower on Wed, but 950 mb temps will actually rise west of the
mountain due to the weak offshore flow. Therefore, expect a few
degrees of warming in most areas on Wed, especially in the valleys
and across interior sections of the coastal plain.

Another strong vort will move south southwestward through the
Great Basin Wed night and Thu, causing a weak closed upper low to
develop over southern Nevada and southwestern Utah, with a trough
extending southwestward into the forecast area. There is still
some uncertainty as to how much stratus will develop Wed night and
Thu morning, but at this point, it does look as though there will
be more extensive low cloud coverage, affecting coastal areas of
L.A./Ventura Counties, the Central Coast and Santa Ynez, and
possibly the lower valleys of L.A. and Ventura Counties. With
lowering heights, cooling at 850 and 950 mb, and increasing
onshore flow, expect a few degrees of cooling in most areas Thu.

.LONG TERM (FRI-MON)...06/234 PM.

An upper low is forecast to cut off in the western portion of the
aforementioned broadly cyclonic flow aloft, meandering along a
highly uncertain track over the southwest states through the
upcoming weekend and early next week. Model solutions vary
significantly regarding the trajectory of this system, resulting
in uncertainty regarding sensible weather elements across the
forecast area.

If the upper low stays farther east across the Four Corners
region and southern Rockies, leaving upper ridging over the
forecast area, then considerably warmer temperatures well into
the 80s will occur in many areas by this weekend and completely
dry weather would occur. This general outcome appears most
probable (50% chance of occurrence). Farther-west tracks of the
upper low close to southern California would correspond to cooler
temperatures and perhaps non-zero precipitation chances -- though
this general solution appears unlikely (10% chance of occurrence).
Upper low tracks in between these two regimes would correspond to
dry conditions and temperatures closer to normal. Patchy low
clouds and fog could return farther inland by this weekend, with
additional rounds of local gusty winds, depending on the track of
the upper low.

&&

.AVIATION...07/1118Z.

At 1030Z, there was no marine layer or inversion at KLAX.

Overall, moderate to high confidence in 12Z TAF package. Thru the
period, high confidence in most sites being CAVU. The only
exceptions will be KPRB (with a 40% chance of IFR conditions
12Z-16Z) and KLAX/KLGB/KSMO (with a 50% chance of CIG/VSBY
restrictions after 09Z).

With gusty winds this afternoon, there is a 50% chance of MVFR
VSBYs in blowing dust for KPMD/KWJF 20Z-04Z.

KLAX...Overall, moderate confidence in 12Z TAF. High confidence in
CAVU conditions thru this evening. For tonight/Wednesday morning,
there is a 50% chance that CIG/VSBY restrictions will not develop
10Z-17Z. No significant easterly wind component is expected.

KBUR...High confidence in 12Z TAF.

&&

.MARINE...07/418 AM.

For the Outer Waters, high confidence in current forecast. Today
through tonight, Gale force winds are expected and GALE WARNINGS
are in effect. For Wednesday and Wednesday night, a combination
of Small Craft Advisory (SCA) level winds and seas are expected.
For Thursday through Saturday, winds and seas will remain below
SCA levels.

For the Inner Waters north of Point Sal, moderate to high
confidence in current forecast. SCA level winds are likely this
afternoon and evening. For Wednesday, there is a 30% chance of SCA
level winds in the afternoon/evening hours. For Thursday through
Saturday, high confidence in winds and seas remaining below SCA
levels.

For the Inner Waters south of Point Conception, high confidence in
current forecast. Across the western half of the Santa Barbara
Channel, SCA level winds are expected this afternoon and tonight.
Otherwise across the southern Inner Waters, winds and seas will
remain below SCA levels through Saturday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory remains in effect from 7 PM this evening to 3
      AM PDT Wednesday for zones 88-350-352-353-376-377. (See LAXNPWLOX).
     Wind Advisory remains in effect from 4 PM this afternoon to 3
      AM PDT Wednesday for zones 349-351-378-381. (See LAXNPWLOX).
     Wind Advisory remains in effect until 9 AM PDT this morning
      for zones 377-378. (See LAXNPWLOX).
     Wind Advisory in effect from 4 PM this afternoon to 3 AM PDT
      Wednesday for zone 383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect from 3 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 Wednesday for zone 650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Wednesday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...DB/Cohen
AVIATION...RAT
MARINE...RAT
SYNOPSIS...Cohen

weather.gov/losangeles

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