Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 260112

512 PM PST Sat Feb 25 2017

Dry and cool conditions will continue today. A couple of weak
weather systems will bring and a chance of rain and mountain snow
tonight and early Sunday, with a chance of showers continuing
through Monday. High pressure will bring clear skies and a warming
trend to the region Tuesday through much of next week, with above
normal temperatures expected Thursday and Friday



A trough of low pressure off the North Coast of California, or
about 550 miles northwest of Los Angeles, will continue to move
southeast into the region tonight. Rain will likely spread into
the Central Coast late this evening, then likely spread south and
east into the Los Angeles Basin just before daybreak Sunday. PoPs
have been nudged a little higher in the latest forecast package,
especially for the Los Angeles Basin into Sunday afternoon.
Rainfall amounts are looking a bit more favorable for areas south
of Point Conception and rainfall amounts should range between 0.25
and 0.50 inch areawide. Local amounts up to 0.75 inch are
possible along southwest and west facing slopes.

Snow levels with this system will fall to between 3500 and 4000
feet between late tonight and into Sunday morning. With the snow
level this low, light accumulations from a dusting to an inch
cannot be ruled out on the Grapevine portion of Interstate 5
between Los Angeles and Kern Counties and on Highway 14 between
Canyon Country and the Antelope Valley. Travel could be impacted
on Sunday morning. Generally, snow accumulation between 1 inch
and 3 inches are expected across the mountains. Local amounts up
to 7 inches cannot be ruled out on favored mountain peaks.

Otherwise, cool and cloudy conditions will persist into at least
Sunday evening along with a slight chance to chance of showers.
The highest chance will be for the Los Angeles Basin, where
moisture and instability lingers into Sunday evening.

A cooler air mass should linger into early next week as a trough
of low pressure over British Columbia phases with a trough near
35N and 145W and moves over the region. Additional shower chances
should linger into at least Tuesday as the troughs combine while
dampening. Additional rainfall amounts between Sunday night and
Tuesday should be a tenth of an inch or less. Any extra snowfall
will amount to an inch or less. South of Los Angeles County, San
Diego and Orange Counties will be in a more favorable flow pattern
and higher rainfall total should be expected across Extreme
Southwest California.


Another trough could move into the region on Wednesday and bring
mainly clouds and possibly showers to the northern slopes of the
mountains, but ridging aloft should take ahold over the area for
the latter part of next week and into the weekend. Warmer and
drier conditions along with the possiblity of gusty Santa Ana
winds should develop between Thursday and Sunday. The warmest days
should be Friday and Sunday when offshore gradients and the ridge
position is in a favorable location respectively.



At 0000Z, there was no marine inversion at KLAX.

Moderate confidence with 00z tafs through 06z this evening. Then
low confidence as Cigs are expected to lower to MVFR and possibly
to IFR conds as approaching rain from the NW will move into
SLO/SBA counties later this evening, then overspread across VTU/LA
counties late tonight into Monday morning. 50 percent chance of
low mvfr cigs at all TAF sites once light rain begins,with 20-30
percent for IFR conds during the peak of the light rain occurring.
with highest chances between 09Z and 16Z. Moderate confidence in
TAF winds and rain timing and intensity.

KLAX...Moderate confidence in 00Z TAF. There is a 50 percent
chance of low MVFR cigs after 09Z with a 20 percent chance of
brief IFR cigs. There is a 30 percent chance that sustained east
to south winds will be 10 kt or greater sometime through 01z. then
once again from 12z to 23z Sunday.

KBUR...Moderate confidence in 00Z TAF. There is a 50 percent
chance of MVFR cigs after 10Z. Moderate confidence in TAF winds
and rain timing and intensity.


.MARINE...25/220 PM...

There is a 30 percent chance of Small Craft Advisory (SCA) levels
this evening into early tonight across the outer waters. Gusty
south to southeast winds are expected to develop across the
southern inner waters Sunday with gusts to around 20 kt and choppy
seas, especially across the San Pedro Channel.

There is a 70 percent chance of SCA conditions Tuesday into
Tuesday night as winds and seas approach SCA levels. There is a 70
percent chance of SCA conditions Wednesday night through Friday.




No significant hazards expected.



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