958
FXUS66 KLOX 060303
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
803 PM PDT Sat Oct 5 2024

.SYNOPSIS...05/125 PM.

An extended period of hot conditions will continue over the
valleys and mountains into Tuesday, hottest today through Monday.
Widespread cooling is expected Tuesday through Friday. Low clouds
will continue to moderate the coastal areas, with dense fog and
low visibilities at times.

&&

.SHORT TERM (SAT-TUE)...05/803 PM.

***UPDATE***

Latest satellite and surface observations indicate stratus/fog
across the coastal plain with some mid-level clouds drifting
northeastward across SLO/SBA counties. Elsewhere, clear skies are
observed. Current sounding data indicates marine inversion remains
quite shallow (under 1000 feet in depth).

Forecast-wise for the immediate short term, no significant issues
are anticipated. With the mid-level clouds moving across SLO/SBA
counties, there may be some virga this evening, but no measurable
precipitation is expected. Therefore, main issue will be the
marine layer stratus/fog. Do not anticipate much, if any,
deepening of the inversion overnight. So, stratus/fog will remain
confined to the coastal plain. There will be some dense fog
through the overnight hours, but expect the coverage to remain on
the patchy side.

Overall, current forecast has good handle on the immediate short
term. So, no significant updates are expected at this time.

***From Previous Discussion***

Valleys and most other inland areas are warming up today as
expected with light offshore flow and strong high pressure aloft.
Temps there generally running 3-6 degrees warmer than Friday and
in some areas as much as as 10 degrees warmer. Quite a different
story for coastal areas, especially south of Pt Conception where
the marine layer has been stuck at the beaches and up to 2 miles
inland all day. Despite the offshore trends temperatures in those
areas have been anywhere from 2-9 degrees cooler than yesterday,
the larger of those trends being in the Downtown LA area.

Models are still showing some additional offshore push Sunday to
the tune of about 1.5mb more offshore than this morning. This
still may not have much impact at the beaches but just inland from
the beaches and into the valleys temperatures should climb at
least a couple degrees, and in some cases across the inland
coastal plain possibly several degrees. But as usual lower
confidence for coastal areas due to the uncertainties with the
stratus coverage. Not seeing much change in the pattern Monday so
for most areas conditions and temperatures should be very similar
to Sunday.

A cooling trend will begin Tuesday as a weak trough pushes onshore
along the West Coast. Most valley area temperatures are expected
to drop at least 5 degrees and some as much as 10 degrees.

.LONG TERM (WED-SAT)...05/223 PM.

The cooling trend will continue through next week with a second
and deeper trough coming through next Friday which will finally
bring most coast and valley area temperatures to slightly below
normal. Otherwise very little interesting weather in the 7 day
period. The most interesting weather feature is just outside of
that period starting next Sunday when several of the EPS ensemble
members continue to indicate the possibility of the first Santa
Ana event of this season. This matches up well with the 12z GFS
which shows a 5.4mb offshore trend next Sunday.

&&

.AVIATION...05/2252Z.

Due to a data outage, current marine layer and inversion height
data is not available for KLAX.

Moderate to high confidence in 00Z TAF package. High confidence in
return of CIG/VSBY restrictions to coastal sites tonight, but
moderate confidence in timing (+/- 3 hours of current forecasts)
and flight category (could range between IFR and VLIFR). Moderate
confidence in MVFR VSBYs for KBUR/KVNY in the 11Z-17Z time frame.
For KPRB/KPMD/KWJF, high confidence in VFR conditions through the
period.

KLAX...Moderate confidence in 00Z TAF. Timing of flight category
changes could be +/- 3 hours of current forecasts. No significant
easterly wind component is expected.

KBUR...Moderate confidence in 00Z TAF. There is a 50% chance that
MVFR VSBYs do not develop overnight.

&&

.MARINE...05/803 PM.

For the Outer Waters (off the Central Coast to San Nicolas
Island), high confidence in the current forecast through Sunday,
as winds will remain below SCA (Small Craft Advisory) levels.
Winds may pick up to SCA level in the far northern portion of the
northern zone (off the Central Coast) late tomorrow. However, for
Monday through at least Friday, there is a 50-70% chance for
widespread SCA level winds and seas. There is a 20-30% chance of
low end Gale Force winds Monday thru Wednesday, mostly from Point
Conception to Point Piedras Blancas.

For the Inner Waters north of Point Sal, high confidence in winds
and seas remaining below SCA levels thru Monday. SCA winds and
seas are possible (30-50% chance) during the afternoon thru
evening hours Tuesday through at least Friday.

For the Inner Waters south of Point Conception moderate to high
confidence in winds and seas remaining below SCA levels through
Monday. However, local SCA level winds are possible during the
afternoon and evening hours near Point Mugu and thru the San Pedro
Channel tomorrow. There is a 20-40% chance of SCA winds for the
western portion of the Santa Barbara Channel Tuesday thru Friday
during the afternoon thru evening hours, with highest chances
Tuesday and Friday.

A shallow marine layer will continue to generate patchy dense fog
across portions of the coastal waters through at least Monday
morning, especially in the overnight thru morning hours.
Visibilities of one nautical mile or less can be expected.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning remains in effect until 8 PM PDT
      Monday for zones
      38-88-342>345-351>353-356>358-369>376-378>380-548. (See LAXNPWLOX).
     Heat Advisory remains in effect until 8 PM PDT Monday for
      zones 341-348. (See LAXNPWLOX).
PZ...NONE.

&&

$$

PUBLIC...MW/Thompson
AVIATION...RAT
MARINE...Lewis/RAT
SYNOPSIS...RK/RS

weather.gov/losangeles

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