653
FXUS66 KLOX 251019
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
319 AM PDT Wed Sep 25 2024

.SYNOPSIS...24/633 PM.

Low clouds and fog will continue across coastal areas through the
week with some afternoon clearing and below normal temperatures.
Valley temperatures are expected to be at or below normal for the
remainder of the week, while the far interior areas will remain
above normal. Otherwise, a quiet weather pattern will continue.

&&

.SHORT TERM (TDY-FRI)...25/301 AM.

Quiet early July like weather will continue through the short
term.

The area will be in between a upper level high to the east and a
large east pac trof to the west with weak SW flow over Srn CA. On
Friday the upper high exerts itself and pushes into the state from
the east. 584 dams hgts today will rise to 590 dam by Friday. At
the sfc gradients will slowly trend offshore as the high pressure
moves closer.

Currently the marine layer is 1600 ft deep and marine layer
stratus covers all of the coasts and most of the vlys including
the Santa Clarita. It will be another day of slow clearing with no
clearing likely at more than a few beaches. Today`s temps will not
change much across the coasts (the SBA south cst will be the
exception as a N to S offshore push will bring some warming). The
Vlys and interior will cool noticeably with 3 to 6 degrees of
cooling like and up to 10 degrees in the Paso Robles area.

The increasing hgts and offshore trends will decrease the marine
layer stratus coverage a little each morning Thu and Fri. Clearing
will be quicker and more complete each day as well. Max temps will
raise a degree or two on Thu and 1 to 3 degrees on Friday.

As mentioned at the top of the discussion this pattern will
produce a temperature distribution that resembles July with the
max temps across the coasts and lower vlys 3 to 6 degrees blo
normal and the interior running 3 to 6 degrees above normal.

.LONG TERM (SAT-TUE)...25/318 AM.

Decent mdl agreement for the weekend. A weak trof is fcst to swing
into the state and knock the upper high down to the SE. Hgts will
fall to 584 or 585 dam. More importantly onshore flow to the east
will increase to 7 or 8 mb. This surge in onshore flow coupled
with the lowering hgts will bring 2 to 4 degrees of cooling to the
area. The increased onshore flow will also great gusty conditions
across the LA mtns and the Antelope Vly.

Not much change on Sunday. Morning stratus will cover most of the
coasts, otherwise skies will be sunny. Max temps will change
little from Saturday and will be 3 to 6 degrees blo normals across
the csts/vlys and 4 to 8 degrees above normal inland.

The mdls diverge and the ensemble spread increases for the
forecast early next week. Despite the lower confidence in the
exact forecast there is good confidence that the benign weather
will continue. Most likely scenario calls for an upper high and
increasing hgts leading to a two day warming trend. Max temps on
Tuesday could reach into the upper 90s in the warmer vlys.

&&

.AVIATION...25/0048Z.

At 0030Z at KLAX, the marine layer was 1500 ft deep. The top of
the inversion was near 2200 ft with a temperature of 28 deg C.

High confidence in IFR or lower cigs/vsbys for coastal TAFs with
low confidence in timing of return to VFR with a 10-30% (highest
nearest the coast) chance that of brief or no return to VFR conds
occur.

Moderate confidence in valley TAFS (KBUR/KVNY/KPRB) with a 10-20%
chance VFR conds prevail for KBUR/KVNY and a 20% chance of IFR
conds KPRB (10-18Z).

High confidence in KPMD and KWJF TAFs.

KLAX...Moderate confidence in TAF. There is a 10% chance for
VV002 cigs and/or vsbys 1/2SM or lower between 04Z and 15Z.
However, there is also a 20% chance for cigs to remain OVC005 or
higher thru the period. High confidence in no significant east
wind component.

KBUR...Moderate confidence in TAF. There is 10% chance VFR conds
prevail thru the period.

&&

.MARINE...24/858 PM.

A low end Small Craft Advisory has been issued for the southern
Inner Waters and southern Outer Waters and is in effect late
Wednesday afternoon through early evening.

For the Outer Waters (Central Coast south to San Nicolas Island),
moderate to high confidence in the forceast. High confidence in
the northern zone (10 to 60 NM off the Central Coast) remaining
below Small Craft Advisory (SCA) level thru Thursday, then there
is a 40-60% chance of SCA winds Thurs afternoon thru evening. In
the two Southern Zones (Pt Sal to San Nicolas Islands), moderate
confidence in conditions remaining sub advisory thru Wednesday
afternoon. Then there is a 40-60% chance of SCA level winds form
Pt Conception to San Nicolas Island in the afternoon thru evening
Wednesday and Thurs. Then, moderate confidence in the Outer
Waters remaining sub advisory Friday thru late Saturday, then
increasing to SCA level thru late Sunday.

For the Inner Waters along the Central Coast, moderate to high
confidence in conditions remaining sub advisory thru the period,
with highest chances (20-40%) of SCA conditions Thurs afternoon
thru evening and late Sat thru late Sun.

For the Inner Waters south of Pt Conception, moderate confidence
in winds and seas remaining below SCA level thru Wednesday
morning. Moderate confidence (50-70% chance) in SCA level winds in
Santa Barbara Channel and from Anacapa Island to Pt Dume and the
San Pedro Channel Wednesday late afternoon thru early evening.
Then, moderate confidence in winds remaining sub advisory thru
Sunday, and increasing Sunday afternoon thru evening in the
Western Portion of the Santa Barbara Channel.

A shallow marine layer will bring at least patchy dense fog thru
Wednesday, especially in the afternoon thru evening hours. Please
refer to our marine weather statement for more information.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory in effect from 2 PM this afternoon to 9
      PM PDT this evening for zones 650-655-676. (See LAXMWWLOX).

&&

$$

PUBLIC...Rorke
AVIATION...Munroe/Lewis
MARINE...Lewis/Munroe
SYNOPSIS...MW/Smith

weather.gov/losangeles

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