Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 080313
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
813 PM PDT Tue Apr 7 2020

.SYNOPSIS...07/732 PM.

Scattered rain and mountain snow showers will continue through
early Friday with light snow on the major passes Wednesday morning.
There is a slight chance of thunderstorms on Wednesday in Ventura
and Los Angeles counties, including across the adjacent coastal
waters. The weekend will be dry with a slow warming trend.

&&

.SHORT TERM (TUE-FRI)...07/147 PM.

The next little wave of showers is indeed moving into LA County
this afternoon with the expectation that it will rotate
counterclockwise tonight and increase shower activity to areas to
the northwest. Models are zoning in on SLO and nrn SB Counties,
particularly the interior portions, as getting the lion`s share
of the precip tonight along with the eastern San Gabriels. Meanwhile
other areas will get less and some areas very little, especially
srn SB and Ventura Counties which will be in a relative donut hole
in the precip coverage. This is still a tricky, and relatively
low confidence forecast given the showery nature of the precip and
the usual unknowns with cutoff lows.

After this moves through later tonight tomorrow`s shower activity
is looking pretty isolated and mostly focused over the mountains.
Models show the upper low moving slowly inland near San Diego
Wednesday afternoon/evening and there is a little instability with
it, though again mostly over the higher terrain, and will leave
in the thunderstorm chances across LA/Ventura counties tomorrow just
in case an isolated storm pops up.

While models differ with the track of the low after it moves
inland there is good overall consensus on increasing shower
activity again late Wednesday night into Thursday as moisture
wraps around the back side of the low. In fact, in all areas
except possibly SLO County more rain is expected to fall Thursday
into Thursday night than tonight and tomorrow. Pops have been
increased during this time as well as QPF, though given that there
isn`t much orographic lift going on and minimal, if any,
convection rain rates should be light to moderate at best and
shouldn`t pose significant issues.

Snow levels today have been at or above 5000` and unless the low
tracks farther north it`s likely they won`t get much lower than
that through the duration of this event. It`s possible the very
top of the Grapevine on Interstate 5 could see a mix of rain and
snow at some point but it`s unlikely to accumulate at pass level.
However, due to the now increased duration of the precip the
current slate of winter hazards has been extended another 24 hours
through early Friday morning.

.LONG TERM (SAT-TUE)...07/152 PM.

A majority of ensemble solutions now showing scattered light
showers continuing in eastern LA County through Friday afternoon
before finally exiting the area by Friday night. After that it
looks dry and warmer with highs getting back to near normal levels
by early next week. Beyond that models look pretty dry the rest of next
week with no wind issues or big temperature swings either way.

&&

.AVIATION...08/0049Z.

At 00Z at KLAX, There was a 10000 ft deep moist layer with no
inversion.

Low Confidence in TAFs Cigs and Vis will vary frequently through
the entire period. There will be periods of rain. MVFR conds will
be most prevalent with some low VFR conds. Isolated IFR conds in
heavier showers. There is a 10 percent chc of a TSTM as any site
through the period.

KLAX...Low Confidence in TAFs Cigs and Vis will vary frequently through
the entire period. There will be periods of rain. MVFR conds will
be most prevalent with some low VFR conds. Isolated IFR conds in
heavier showers. There is a 10 percent chc of a TSTM through the
period. High confidence in an east wind component remaining below
5 kt.

KBUR...Low Confidence in TAFs Cigs and Vis will vary frequently through
the entire period. There will be periods of rain. MVFR conds will
be most prevalent with some low VFR conds. Isolated IFR conds in
heavier showers. There is a 10 percent chc of a TSTM through the
period.

&&

.MARINE...07/135 PM.

High confidence that winds and seas will remain below SCA level
through the forecast period.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Winter Weather Advisory in effect until 5 AM PDT Friday for
      zone 52. (See LAXWSWLOX).
     Winter Storm Warning in effect until 5 AM PDT Friday for
      zones 53-54. (See LAXWSWLOX).
PZ...NONE.

&&

.HAZARD POTENTIAL OUTLOOK (FRI-TUE).

Lingering snow showers are possible in the LA County mountains
Friday.

&&

$$

PUBLIC...MW/Rorke
AVIATION...Rorke
MARINE...Sweet
SYNOPSIS...MW/Kj

weather.gov/losangeles


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