558
FXUS66 KLOX 191709
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1009 AM PDT Sat Oct 19 2024

.SYNOPSIS...19/954 AM.

Santa Ana winds will continue through this afternoon. Today will
be at least a few degrees warmer than yesterday in most locations,
and low humidities will continue to impact much of the area. A
slight warm up each of the next several days will continue to
bring above normal temperatures to most of the area through much
of next week. Fairly light winds are expected to accompany the
warm temperatures once the Santa Ana winds subside later today.

&&

.SHORT TERM (TDY-MON)...19/1005 AM.

***UPDATE*** No updates were needed this morning to the forecast.
 Windy conditions and very dry air will continue to be the main
 concerns for the short term forecast. Please see the updated fire
 weather discussion for more details.


***From Previous Discussion***

Clear skies across the entire region this morning. Skies will be
sunny today except for a few high clouds. W-E pressure gradients
were offshore between KLAX and KDAG. N-S gradients were also
offshore, but have begun to weaken across SLO and SBA County.
Gusty NE winds were affecting the mtns and northern and western
valleys of L.A. County, the Santa Monica Range, the Ventura County
valleys, and the Malibu area. Winds were mostly just below
advisory levels, with a few gusts to near 50 in the windier
locations. However, winds are expected to increase and become more
widespread around or just after sunrise, with gusty winds also
spreading into the Ventura County coast. While upper support for
winds will be weaker than it was Fri, gradients will be more
strongly offshore. Therefore, expect widespread advisory level
winds again today in the mtns of L.A. County including the Santa
Monicas, northern and western valleys of L.A. County, the VTU
County coast/valleys and the Malibu area. Winds will drop below
advisory levels in most areas by mid afternoon.

An upper low was centered near Phoenix early this morning. This
low will move little today and tonight, then begin to move slowly
northeastward Sunday, reaching southwestern Colorado by evening.
Heights and thicknesses will rise a bit over the region today, and
temps at 950 mb will edge upward. Do not expect too much change
in max temps today, though there may be a touch of warming,
especially in the Antelope Valley as the mtns due to height rises.
Expect the warmest weather today, just like on Friday, to be in
the lower valleys and across interior sections of the coastal
plain. Max temps could approach 85 degrees again in these areas.

The upper low will move through Colorado and into the Midwest Sun
night and Mon. Heights will rise a bit across the region both Sun
and Mon. Gradients will be offshore each night, but turn onshore
during the afternoon hours. Expect generally clear skies thru Mon,
although some night through morning low clouds and fog could push
into the Central Coast and coastal sections of L.A. County Sun
night/Mon morning.

Due to clear skies and dry conditions, tonight will be a rather
chilly night across the interior. There could be local frost in
the coldest wind-sheltered locations in the Antelope Valley and
the interior valleys of SLO County tonight. Max temps will likely
rise both Sun and Mon in the Antelope Valley and in the mtns.
West of the mountains, expect mostly minor changes in max temps,
as a return to onshore flow during the afternoon will offset
height rises. Overall, max temps should be 4 to 8 degrees (and
locally 10 degrees) above normal in most valley and interior
coastal plain locations. Near the coast, there may be a bit of
cooling, especially on Mon.

.LONG TERM (TUE-FRI)...19/555 AM.

The long range forecast thinking has changed little. Heights
across the region will rise on Tue as an upper high over southern
Texas and Mexico moves westward and expands into the area. The
upper high will hold strongly into Wed. There will be some
offshore N-S gradients Tue/Tue night, with W-E gradients turning
offshore Wed morning. Expect mostly clear skies Mon night thru
Wed, except for some night/morning low clouds and fog near the
coast. There should be a few degrees of warming Tue, with max
temps approaching or exceeding 90 degrees in the warmest valley
locations. Max temps on Wed will be quite similar. While max temps
will be well above normal for late October, do not expect any
records, as daily records for both days are generally in the 97 to
105 degree range in most coastal and valley areas.

A large broad trough will move into the eastern Pacific Thu and
move into the West Coast Fri. Heights will fall Thu and Fri, and
flow will turn onshore and increase. The upper flow will become
southwesterly which may bring increasing high clouds into the
region. The marine layer will likely deepen, with night thru
morning low clouds in coastal and possibly lower valley areas Wed
night/Thu morning, likely pushing father inland Thu night/Fri
morning. Max temps should drop several degrees in most areas both
Thu and Fri, with high back to near normal levels by Fri.

&&

.AVIATION...19/1622Z.

Over KLAX at 16Z, there was no marine layer. The surface
inversion top was at 1500 feet at 18 Celsius.

High confidence in VFR conditions through at least Sunday. Weak
LLWS potential exists through 21Z today at KCMA KOXR KVNY KBUR,
but high confidence in far less LLWS and UDDF over the area
compared to yesterday.

KLAX...High confidence in VFR conditions through at least Sunday,
with no wind concerns.

KBUR...High confidence in VFR conditions through at least Sunday,
with no wind concerns.

&&

.MARINE...19/922 AM.

Moderate confidence in a few hours of northeast winds gusting to
around 20 knots for a few hours this morning off of Malibu to
warrant a Small Craft Advisory (SCA). Moderate confidence in west
winds around 15 knots south of Point Conception this afternoon
and evening. Otherwise, high confidence in abnormally light winds
everywhere through Monday morning with lowering seas. West to
northwest winds increase Monday afternoon and evening, with a 30%
chance of SCA winds south of Point Conception. Moderate to High
confidence in SCA northwest winds for the waters 10+ miles off the
Central Coast to San Nicolas Island Monday Night through
Wednesday.

Dense fog potential will grow Monday and Tuesday, but far from
certain.

&&

.FIRE WEATHER...19/955 AM.

An upper level low pressure system, currently sitting over
Arizona, will slow move to the northeast over the weekend.
Widespread very dry air will remain over much of the region today,
with minimums between 5 and 15 percent common and poor overnight
recoveries of 15 to 30 percent in the mountains and foothills.
Santa Ana winds will be somewhat weaker today as compared to
yesterday, however northeast winds gusting between 25 and 45 mph
will be common today across the wind prone areas of LA and Ventura
counties, where the Red Flag Warning is in effect. Over Santa
Barbara and San Luis Obispo Counties, the combination of very dry
conditions and locally breezy conditions will bring elevated to
brief critical fire weather conditions today across interior
areas. High temperatures will warm over the weekend with highs
between 75 and 85 common. High confidence in improving conditions
with generally light winds for Sunday and Monday, but elevated
concerns will persist through Wednesday as warm and dry conditions
persist.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory remains in effect until 3 PM PDT this afternoon
      for zones 88-354-355-358-362-369>375-379-380. (See LAXNPWLOX).
     Red Flag Warning in effect until 6 PM PDT this evening for
      zones 288-358-369>376-378>380. (See LAXRFWLOX).
PZ...Small Craft Advisory in effect until noon PDT today for zone
      655. (See LAXMWWLOX).

&&

$$

PUBLIC...DB/JMB
AVIATION...Kittell
MARINE...Lewis/Kittell
FIRE...Gomberg
SYNOPSIS...Lewis/JMB

weather.gov/losangeles

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