Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 220558

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
958 PM PST Sun Jan 21 2018

Conditions will be primarily warm and dry through early next
week, though there is a slight chance of light showers along the
Central Coast on Monday. A weak cold front will push through the
region later in the week, bringing cooler temperatures, gusty
winds, and possible rain and mountain snow showers.


.UPDATE...A weak upper level disturbance system crossing Northern
California will bring a slight chance of rain to the far NW
portion of the Central Coast late tonight into Monday. Mid to
upper level clouds will stream over the area, but little or no
rain is expected for SW California...except perhaps a hundredth or
two north of Cambria. As this system exits a weak ridge of high
pressure will begin to build over the West Coast, with weak
northerly gradients in place at the surface. At the present time,
north winds are gusting up to 20 mph in some of the L.A./Ventura
Valleys, and up to 25 mph in the L.A./VTA mountains. This should
keep low temperatures a few degrees higher than the last couple of
nights for most locations. The ridge aloft will produce a warming
trend through the next 2-3 days, with highs on Monday warming by around
3-6 degrees.



Ridging aloft will build back in for Tuesday and bring continued
warming. A developing shortwave trough spinning counter- clockwise
around the Aleutian low pressure system will phase with a wave
over the North Central Pacific Ocean and eject toward the West
Coast through Wednesday.


A cold frontal boundary will approach the region on Wednesday
night and move across the area on Thursday. Model solutions
indicate ample moisture for the possibility of precipitation. The
main question is if the westerly flow pattern will hold together
south of Point Conception. A majority of GFS ensemble members
suggest measurable falling as far south as Ventura County, which
agrees with the ECMWF/GFS solutions. PoPs have been nudged higher,
especially north of Point Conception. Rainfall amounts will
likely range from 0.10 inch or less south to Point Conception up
to 0.10-0.25 inch north of Point Conception. The main impact will
be colder temperatures Thursday and Friday, snow levels lowering
to as low as 3000-4000 feet Thursday, and gusty winds along and
behind the cold front. Snowfall could impact the Grapevine portion
of the Interstate 5 Corridor.

Ridging aloft looks to establish once again between Friday and
Saturday. Offshore flow could reach advisory levels over the
weekend and bring gusty Santa Ana Winds to the region between
Friday night and Sunday, possibly lingering into Monday. The
ridge axis should move over the region through next weekend,
setting up for a warm, dry, and breezy to windy weekend.




At 0523Z at KLAX, there was no marine inversion.

High confidence in CAVU TAFs.

KLAX and KBUR...High Confidence in CAVU TAF.



21/800 PM

Across the southern outer waters zones (PZZ673, PZZ676) SCA conds
for seas are likely much of the time Mon through Tue night due to
a combination of winds and seas.

Across the northern outer waters zone (PZZ670) SCA conds are
likely again Mon thru Mon night due to seas, with the SCA seas
expected to move into the nearshore waters north of Point Sal
during this time as well (PZZ645).

Across the SBA Channel and the southern inner Waters, SCA conds
are not expected until Thu.

A long period NW swell will arrive in the water late tonight,
rising to 10 to 13 feet by Monday. Another long period swell is
expected Thu into Fri.


CA...High Surf Advisory in effect from 4 AM Monday to 4 AM PST
      Tuesday for zones 34-35. (See LAXCFWLOX).
PZ...Small Craft Advisory for hazardous seas in effect from 3 AM
      Monday to 4 AM PST Tuesday for zones 645-670. (See LAXMWWLOX).
     Small Craft Advisory in effect until 3 AM PST Wednesday for
      zone 673. (See LAXMWWLOX).
     Small Craft Advisory in effect from 3 AM Monday to 3 AM PST
      Wednesday for zone 676. (See LAXMWWLOX).


Strong and impactful winds are possible Thursday and Friday over
the mountains and southern Santa Barbara County. Snow and travel
delays are possible over the Tejon Pass/Grapevine area late
Thursday into Friday. Gusty Santa Ana winds could develop over
next weekend.



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