241
FXUS66 KLOX 151013
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
313 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)...15/237 AM.

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...15/0613Z.

At 16Z at KLAX, the marine layer was 700 ft deep. The top of the
inversion was 2300 ft with a temperature of 26 C.

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

Low confidence in TAF for KLGB with a 40 percent chc of no cigs
in the morning.

Moderate confidence in TAF for KSMX with a 20 percent chc of no
low clouds and a 30 percent chc of a 17Z VFR transition if low
clouds do develop.

Moderate confidence in all other TAFs. There is a 25 percent chc
of LIFR/IFR cigs and IFR/MVFR vis at all sites 11Z-17Z.

KLAX...High confidence in TAF except from 11Z-16Z. Where there is
a 25 percent chc of 3SM BR OVC005 conds. Good confidence that any
east wind component will remain under 5 kt.

KBUR...High confidence in CAVU TAF.

&&

.MARINE...14/831 PM.

For the offshore waters from the Central Coast to San Nicolas
Island (the outer waters), there is a 70% chance of gales
increasing to a 90% chance for Thursday night. Winds will be
strongest during the late afternoon through late evening hours.
High confidence of SCA level winds following the gales through at
least the weekend.

For the nearshore waters of the Central Coast, moderate
confidence in SCA level winds and/or steep seas through Thursday,
especially in the afternoon and evening hours. Chances of SCA
lower Friday through the weekend.

For the Santa Barbara Channel, high confidence in SCA levels winds
over the far western portion each afternoon and evening through
Thursday, with a 50% chance of SCA winds extending across the
entire western half. Moderate confidence that the eastern portion
will stay under SCA levels. Over the weekend, there is a 40%
chance of SCA level winds over the western half of the channel
during the afternoon and evening hours.

For the waters off of Los Angeles and Orange Counties, other than
local gusts to 20 to 25 knots in the San Pedro Channel, high
confidence in conditions staying under SCA levels.

High confidence in building short period seas through Friday
morning nearly everywhere, including the nearshore waters.

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

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect until 5 AM PDT Friday for zone
      645. (See LAXMWWLOX).
     Small Craft Advisory in effect from noon today to 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
AVIATION...Rorke
MARINE...RK/Lewis/Lund
SYNOPSIS...RS/KL

weather.gov/losangeles

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