000
FXUS66 KLOX 082056
AFDLOX

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
156 PM PDT Wed Apr 8 2020

.SYNOPSIS...08/1143 AM.

Scattered rain and mountain snow showers will continue through
early Friday along with below normal temperatures. Saturday
through Wednesday will be dry with a slow warming trend to near
normal.

&&

.SHORT TERM (TDY-SAT)...08/125 PM.

Great view of our tightly wrapped cutoff low on GOES-17 satellite
imagery spinning just west of San Nicolas Island this afternoon.
Showers today have been mostly confined to LA County and in the
mountains. While the upper level flow is mostly from the east the
winds at lower levels are still primarily from the southwest and
this will help precip become more widespread across the area
tonight as the low moves onshore. Models have been pretty
consistent last couple days showing steady light to moderate
precip developing across the entire 4 county area overnight and
continuing much of Thursday, tapering off from the northwest in
the afternoon as the lower level winds shift to northeast. Even
with the wind shift to northeast it will likely take most of the
night and even into Friday before showers taper off completely in
LA County, and actually the northeast flow will be favorable for
continuing upslope showers in the eastern San Gabriels Friday.

So a pretty wet period over the next 36-48 hours. The saving grace
is that instability is minimal and rain rates are not expected to
pose significant issues, though brief periods of heavy rain are
likely at times as some of the stronger cells moves through.
Doesn`t look like there`s enough for thunder but it`s not a zero
chance. Additional rainfall amounts are expected to range from
.5-1" coast/valleys (slightly less north of Pt Conception) and
1-2" mountains.

In the mountains this will continue to be a huge snow maker with
some areas in the eastern San Gabriels already having received
over 30" of snow since Sunday. That same area is likely to receive
another 12-24" of snow through Sunday while other mountain areas
above 6000` will see an additional 6-12". Still not expecting this
to pose any significant issues to the Grapevine on Interstate 5
but there could be some brief periods of rain/snow mix at pass
level.

Showers expected to taper off by Friday but still a fair amount of
lower level moisture especially in LA County. Any additional
precip at that point should be very light.

Friday night and Saturday models show a fairly deep marine layer
developing across all coast/valley areas and possibly even up the
lower coastal mountain slopes. Most areas should clear enough for
some sunshine in the afternoon and temps should warm up from
Friday but still be a couple degrees below normal.

.LONG TERM (SUN-WED)...08/154 PM.

Fairly benign weather after Saturday though not necessarily high
and dry. A broad upper level trough will cover much of the US
Sunday into Monday. On Sunday a weak impulse moves down the west
side of the trough and by late Sunday night will be passing
through southern California. That`s not a favorable trajectory for
precip locally, however models do show some very small amounts,
possibly from a deep marine layer Monday morning. Will hold off
going with any precip chances yet but will continue to monitor.

Heights rise Tue for some additional sunshine and slight warming,
but then a little cooler Wed as another little inside slider drops
into the Great Basin. Models favor that pattern continuing into
next weekend at least and while currently they are staying too far
east to have any real precip chance it`s something to keep an eye
on as we get closer. At the very least they will keep temps near
to slightly below normals through the period with possibly some
marine layer clouds at times.

&&

.AVIATION...08/1746Z.

At 1627z at KLAX...there was no inversion.

Low to moderate confidence in the current TAFs. Precipitation and
associated MVFR/local IFR CIGs will continue to move through the
region during the forecast period. CIGs and at times the vsby will
vary frequently through the forecast period, especially during
periods of showers.

KLAX/KBUR... Low to moderate confidence in the current TAF. Rain and
associated low CIGs will move toward the airfields from almost any
direction with the storm center almost directly overhead. CIGs
and at times the vsby will vary frequently through the forecast
period, especially during periods of showers. MVFR/VFR conditions
will be most prevalent with local IFR conditions near heavier
showers. At KLAX, there is a ten percent chance of east winds
greater than 8 kts early Thursday 12z-17z.

&&

.MARINE...08/123 PM.

Conditions will remain below advisory level through Friday with
winds increasing across the outer waters Saturday and Sunday.

&&

.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 (SAT-WED).

No significant hazards expected.

&&

$$

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

weather.gov/losangeles




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