Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 190624

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
1024 PM PST Sat Nov 18 2017

Surface high pressure over the Central Rockies will continue to
supply a cool and dry air mass to the region with another round of
frost and freeze conditions for cooler interior areas through
Sunday morning. A ridge of high pressure building into the region
early next week will bring significant warming with widespread
record heat possible mid-week, including Thanksgiving day.



Clear skies covered the forecast area this evening with little
change expected overnight. Gusty sub-advisory level NE winds were
noted this evening mainly across the foothills and mtns of VTU/L.A.
Counties. Pressure gradients for LAX-DAG at 03Z was -4.6 mb which
was stronger than the 00Z NAM was predicting. The good offshore
gradients will persist overnight with the gusty NE winds expected to
continue in these areas. For the Antelope Vly and interior vlys of
SLO/SBA Counties, light winds, clear skies and a dry air mass will
result in good radiational cooling tonight. Low temps in these areas
are expected to drop into the mid 20s to low 30s, and Freeze
Warnings and Frost Advisories are in effect overnight into Sun
morning. Please see the latest Non-Precipitation Weather Message
(LAXNPWLOX) for further details on the Freeze Warnings and Frost

A flat upper ridge over srn CA this evening is forecast to slowly
build over the area Sun thru Tue, with 500 mb heights rising to 588
to 590 dm by Tue afternoon.

Dry weather with a gradual warming trend is expected across the
region Sun thru Tue. Mostly clear skies for the most part will
prevail Sun and again on Tue, while a weak disturbance moving N of
the region should bring mainly mid and hi clouds clouds to the area
Sun night into Mon night, with partly to mostly cloudy skies
expected. Some offshore low level flow night and morning hours will
persist thru Tue, keeping any low clouds off the coast.

Temps will be a few degrees above normal for most areas on Sun, then
increase to much above normal by Tue. Highs in the warmest vlys and
inland coastal areas are expected to reach the mid 70s to around 80
on Sun, upper 70s to lower 80s Mon, and mid 80s to around 90 on Tue.



Wednesday and Thanksgiving Day expected to be the warmest days of
the week, as the upper level ridge of high pressure continues to
strengthen, with heights peaking at 592 DM. During this time,
temperatures could reach record levels, with highs in the lower
to mid 90s across many valley areas, and possibly inland portions
of the coastal plain. The unseasonably hot and dry conditions
combined with breezy offshore conditions will continue to bring
elevated fire weather concerns during the extended period. The
upper level ridge flattens out Friday and this will bring some
cooling to all areas but especially the coast. Additional cooling
and increasing high clouds expected by next Saturday as a weather
system approaches the California coast.



At 0530Z, there was a surface based inversion at KLAX. The top of
the inversion was at 1300 ft with a temperature of 21 deg C.

Clear skies and VFR conds expected across the region thru the pd.
There will be locally gusty ne winds thru and below passes and
canyons in the mtns and valleys of L.A./VTU Counties overnight
thru mid to late morning Sun with local LLWS and moderate UDDF.

KLAX...High confidence in the 06Z TAF. VFR conds thru the pd.

KBUR...High confidence in the 06Z TAF. VFR conds thru the pd.


.MARINE...18/830 PM.

Winds across the outer waters will increase on Sunday and there
is a forty percent chance of speeds reaching SCA levels during the
Sunday night through Monday night period.


CA...Frost Advisory in effect until 9 AM PST Sunday for zones
      36-38-44. (See LAXNPWLOX).
     Freeze Warning in effect until 9 AM PST Sunday for zone 37. (See LAXNPWLOX).
     Hard Freeze Warning in effect until 9 AM PST Sunday for zone
      59. (See LAXNPWLOX).


No significant hazards expected.



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