579
FXUS66 KLOX 151654
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
954 AM PDT Thu Aug 15 2024

.SYNOPSIS...14/800 PM.

Daytime highs will be near normal for most areas through the
weekend, followed by a warm up early next week. Patchy overnight
into morning low clouds and fog will impact coastal areas at
times. Gusty winds are likely across Southwest Santa Barbara
County and the Antelope Valley during the evening into overnight
hours through Thursday night.

&&

.SHORT TERM (TDY-SAT)...15/951 AM.

***UPDATE***

Last night advisory level Sundowner winds occurred across the
Santa Barbara Southwest Coast and Western Santa Ynez Mountains, as
well as locally gust winds across the eastern portion of the
mountains. While the general trend across high resolution models
shows a slight decrease in winds tonight, there remains a 50-70%
chance of northwest winds tonight gusting at 35 to 50 mph. A Wind
Advisory has been issued from 4 PM this afternoon through 3 AM
tomorrow morning for the Santa Barbara Southwest Coast and
adjacent mountains.

Marine layer cloud coverage this morning was confined to west-
facing Santa Barbara County, and currently clouds are dissipating
quickly. Weak onshore pressure gradients, increasing 500 mb
heights, and clear skies, set the stage for a few degrees of
warming today across the region.

***From Previous Discussion***

Three days of uneventful weather on tap for Srn CA. At the upper
levels a very warm upper high will slide over the CA/Mexico border
and into New Mexico today and Friday. On Saturday a cool (at least
for mid August) will approach the CA/OR border and this will push
hgts down. At the sfc there will be weak to moderate onshore flow
to the east and weak occasionally offshore flow in the N/S
direction.

Today and Friday will be very similar days. The lack of an eddy or
any other source of low level lift will really suppress marine
layer cloud formation and skies will be mostly clear over the next
48 hours. The only exception will be the western portion of SBA
county where there will be some morning low clouds. The SW tip of
LA county has a chc of some low clouds as well.

Almost all areas will see 3 to 5 degrees of warming today with the
only the LA/VTA county coasts excluded. Most of the vlys will be a
few degrees above normal today while the coasts and the interior
will be a few degrees blo normal. One notable exception will be
the SBA south coast where a N to S offshore push across the county
will boost temps 5 to 10 degrees above normal. Look for another 2
to 4 degrees of warming on Friday everywhere except the SBA county
south coast and the VTA county cst/vlys where a little better W to
E onshore push will bring a few degrees of cooling.

It will be noticeably cooler on Saturday. The approaching upper
low will lower hgts. In addition the lower hgts and better onshore
flow will bring more marine stratus to the coasts in the morning.
The lower hgts, deeper marine layer and stronger onshore flow
will all conspire to lower max temps 2 to 5 degrees. Most max
temps will come in 2 to 4 degrees blo normal.

The N to S offshore push across SBA county produced low end
advisory level gusts last evening and will likely produce another
round of advisory level Sundowner gusts tonight into early Friday
morning. The strongest gusts will occur near Gaviota.

The upper level flow pattern is not conducive to monsoonal flow
and the threat of afternoon convection is low - well under 10
percent.

.LONG TERM (SUN-WED)...15/312 AM.

Mdls and ensembles have come into better agreement for the xtnd
fcst. During the period big 598 dam upper high will slow push to
the west moving from the TX panhandle to western NM. Hgts over
Srn CA will climb from 590 dam to 594 dam. The sfc pressure
pattern will not change much during the period with weak to
moderate onshore flow to the east and weak onshore flow to the N
in the afternoon followed by weak offshore flow to the S in the
early mornings.

There will be little in the way of marine layer clouds as the
extra high hgts will keep the marine layer smooshed to under 800
ft. In addition there will be not be any low level lifting
mechanisms that would help to generate clouds.

Max temps will be the main talking point of the xtnd fcst with a 4
day warming trend on tap. Max temps will climb 1 to 3 degrees per
day Sun through Tue with perhaps a degree or two of additional
warming on Wed. By Wed the only 70s will be right at the beaches
with 80s and lower 90s across the rest of the coasts. The vlys
will see max temps in the 90s to 102 degrees. There will be plenty
of triple digit heat across the far interior and lower mtn
elevations as well. These max temps are 3 to 6 degrees above
normal. While rather warm these temps are a few degrees below
critical heat advisory thresholds.

The flow pattern on Tue and Wed is mildly conducive to monsoon
flow. Only a few ensembles pick up on any flow and right now the
chc of afternoon convection remains less than 10 percent. Still
days 6 and 7 are a ways off and this fcst could change.

&&

.AVIATION...15/1132Z.

At 1034Z at KLAX, the marine layer was 400 ft deep. The top of
the inversion was 3000 ft with a temperature of 24 Celsius.

Very high confidence in VFR conds for KPRB, KBUR, KVNY, KPMD,
KWJF.

Moderate to high confidence in all other TAFs, except KLGB and
KSMX where there is low confidence through 16Z. There is a 50%
chance that VFR conds at KSMX prevail through the period, and a
40% of VFR conds at KLGB. There is a 30% chance of cigs at KSBP
through 16Z. Moderate confidence in any ceilings being LIFR- IFR
at KSBP and KSMX, and IFR- MVFR at KLGB. Good confidence in cigs
clearing by 16Z.

KLAX...Moderate to high confidence in TAF. There is a 20% chance
of OVC008-012 cigs through 16Z Thurs, and 09Z-16Z Fri. Good
confidence that any east wind component will remain under 5 kt.

KBUR...High confidence in VFR TAF.

&&

.MARINE...15/936 AM.

For the offshore waters from the Central Coast to San Nicolas
Island (the outer waters), high confidence in Gale force wind
gusts through late tonight, with the strongest winds occuring in
the late afternoon through late evening hours. High confidence in
Gales subsiding late tonight, with SCA level winds thru at least
the weekend.

For the nearshore waters of the Central Coast, moderate
confidence in SCA level winds and/or steep seas through late
tonight, with strongest winds in the afternoon and evening hours.
Chances of SCA conditions are lower Friday, and even lower
through the weekend.

For the Santa Barbara Channel, high confidence in SCA levels
winds over the far western portion this afternoon thru late
night. Moderate confidence in conditions remaining below SCA
level tomorrow, but higher chances over the weekend. In the
Eastern portion, high confidence in conditions remaining below SCA
level thru the weekend.

For the waters off of Los Angeles and Orange Counties, high
confidence in conditions staying under SCA levels through the
weekend.

With a shallow marine layer, high confidence in dense fog with
visibilities under 1 mile effecting the Central Coast waters
through at least tomorrow morning.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect from 4 PM this afternoon to 3 AM PDT
      Friday for zones 349-351. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 5 AM PDT Friday for zone
      645. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PDT Friday for zone
      650. (See LAXMWWLOX).
     Gale Warning in effect until 3 AM PDT Friday for zones
      670-673-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke/Schoenfeld
AVIATION...Lund
MARINE...RK/Lewis/Lund
SYNOPSIS...RS/KL

weather.gov/losangeles

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