Area Forecast Discussion
Issued by NWS Los Angeles, CA

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942
FXUS66 KLOX 251144
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
344 AM PST Sat Nov 25 2017

.SYNOPSIS...
Above normal temperatures are forecast on Saturday. A low will
arrive Sunday for possible precipitation from Santa Barbara and
northward, then the possibility of precipitation should spread to
Los Angeles by Sunday night, and into Monday. A high should build
in next week for partly cloudy skies, offshore winds, and above
normals Tuesday into Friday.

&&

.SHORT TERM...(TDY-MON)

One last day of mostly sunny skies and above normal temps brought
on by an upper level ridge and weak offshore flow. Max temps will
be about 12 to 18 degrees above normal.

Tonight the upper ridge will be pushed to the south and east as a
Gulf of Alaska low plows into the PAC NW. The offshore flow will
turn weakly onshore and low clouds will likely develop over the
coasts of VTA and LA counties. Skies over SLO and SBA counties
will turn mostly cloudy as mid and high level clouds move into the
area from the NW.

A trof with a developing upper low at its base will move closer to
the Central Coast on Sunday. Clouds will increase and thicken over
SLO and SBA counties while VTA and LA counties will have partly
cloudy skies. Onshore flow returns and hgts will fall. Max temps
will cool across the area with the greatest drops north of Pt
Conception. Most of the area will not see rain during the day
except for the coastal areas from Cambria north later in the
afternoon.

South to Southwest winds will increase over the area Sunday
afternoon and overnight as the system approaches.

On Sunday night the upper low at the base of the trof will be
fully formed and it will move into the Bay Area towards dawn on
Monday. Rain will develop over SLO and SBA counties and there will
be a chc of rain over VTA county.

The trof and a weak sfc front will race through the area on Monday
morning. Monday will be cloudy day and there will be at least a
slight chc of rain everywhere. The best chc of rain will be over
the interior vlys and the mtns. Rain will taper off quickly early
in the afternoon as NVA moves in behind the front. A small chc of
showers will persist in the mtns. Max temps will collapse 8 to 12
degrees across the area and max temps will be 3 to 6 degrees blo
normal.

Rain totals forecast through Monday will be one quarter to one
half inch for Santa Barbara and San Luis Obispo Counties, with
close to an inch near Rocky Butte, up to one tenth in the Ventura
Mountains, and less for the remainder of Ventura and L.A.
Counties.

Gusty southwest to west winds Monday morning will shift to the
northwest Monday afternoon, then increase to near-advisory levels
in the evening.

.LONG TERM...(TUE-FRI)

The GFS and the EC are not in the greatest of agreement for the
extended period and both have not exhibited much in the way of run
to run consistency either. This is a prime indication that the
extended forecast is going to be pretty changeable.

Right now the forecast calls for a fast moving ridge to pop up on
Tuesday and then move out only to be replaced by a cull area on
Wednesday. Both mdls move an upper low in from the SW on Thursday
but the GFS places the upper low close enough to forecast rain
while the EC`s position is too far west for rain. On Friday the
GFS continues to advance the low and which continues the threat of
rain. The EC barely moves the low at all and is dry.

At one time fairly dramatic offshore flow was forecast either on
Tuesday or Thursday now there is just some weak to moderate
offshore flow forecast.

Pretty confident that Tuesday will be mostly sunny and will have a
solid 8 to 12 degrees of warming.

For the remainder of the forecast favored the dry EC solution as
the GFS just seems too progressive given the size of the ridge to
the east of the area. Max temps will cool some Wednesday and then
change little each day Thu and Fri.

Both the EC and the GFS are wet for next weekend but the mdls have
been too inconsistent to place any great amount of faith in their
day 8 and 9 solutions.

&&

.AVIATION...25/11Z

At 0910Z at KLAX, there was no marine layer. There was a sfc
based inversion. There top of the inversion was at 2200
feet with a temperature of 24 degrees C.

Expect VFR conds through this evening, with just some high
clouds. There could be local MVFR vsbys through 18Z due to mist or
haze in some coastal areas. Expect low clouds on the Central
Coast and across coastal sections of L.A. and VTU counties tonight
beginning around or just before midnight, with LIFR to VLIFR
conds expected.

KLAX...Moderate to high confidence in the 12Z TAF. There is a
20-30% chc of MVFR vsbys through 18Z, and a 10 percent chc of
LIFR cigs between 12Z and 16Z. There is a 20% chance that cigs
will arrive as early as 04Z this evening.

KBUR...High confidence in the 12Z TAF with VFR conds thru the pd.

&&

.MARINE...25/300 AM.

Good confidence in the forecast for the Outer Coastal Waters and
the northern inner waters. Conditions will likely be below SCA
levels through early Sunday night. There is a 20 percent chance
that there will be some SCA level S-SE wind gusts this afternoon
thru tonight. SCA level W-NW winds are expected late Mon thru Mon
night, possibly beginning as early as late Sun night. SCA conds
will likely linger thru Tue due to winds and seas across the
outer waters, and due to seas across the northern inner waters,
then due to seas in all areas Tue night and Wed.

Across the inner waters and the SCA Channel, expect conds to
remain below SCA levels thru Mon morning. SCA conds are likely
due to winds and seas Mon night, and possibly as early as Mon
afternoon. Seas will remain rough and choppy Tue.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.

&&

.HAZARD POTENTIAL OUTLOOK...(MON-FRI)
Between Sunday and Monday night, a storm system moving into the
region from the Gulf of Alaska could bring rain, high- elevation
snow and gusty west to north winds. After the storm passes,
offshore flow will likely develop and there is the potential for
elevated to near critical fire weather conditions Tuesday through
Thursday for portions of Southwest California. High surf is
possible at Southern California beaches between Monday and
Tuesday, and again between Wednesday and Thursday.

&&

$$

PUBLIC...Rorke
AVIATION...DB
MARINE...DB
SYNOPSIS...STu

weather.gov/losangeles



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