Acton Weather

000
FXUS66 KLOX 230022
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
422 PM PST Sat Feb 22 2020

.SYNOPSIS...22/413 PM.

Scattered showers and isolated thunderstorms will continue
through early this evening for Ventura and Los Angeles Counties.
Clearing tonight into Sunday will be followed by offshore winds
and above normal temperatures through much of the coming week.

&&

.SHORT TERM (TDY-TUE)...22/240 PM.

Shower activity has finally picked up some across the area early
this afternoon especially across Ventura and LA Counties. Daytime
heating has allowed to help destabilize the atmosphere and produce
a few short-lived thunderstorms. Small hail was reported in a
couple of these storms, including over Downtown LA, Woodland
Hills, and Simi Valley. The slight chance for thunderstorms will
continue through the afternoon, mostly focused over southern LA
County and adjacent coastal waters.

As expected, rainfall has been quite light across the region, with
amounts so far generally under a tenth of an inch. The highest
totals so far have been over the hills around Montecito in Santa
Barbara County where a gauge has reported 0.89 inches thanks to a
thunderstorm over that area earlier this morning. A couple spots
that were impacted by a thunderstorm have exceeded 0.25 inches.
Scattered showers will continue through the afternoon, then start
to shut off from west to east during the evening as the low
continues to move eastward.

Earlier forecasts indicated the upper low would move into Orange
County by noon then accelerate towards Las Vegas by early evening.
However, it looks like it will stay more south and move a little
slower. Now models are indicating it will make its way into
western Arizona by tonight. A slight chance of rain will remain
through the night for the mountains of Ventura and LA Counties
with any wraparound moisture.

Not much change for rainfall totals since the showery nature tends
to produce highly variable amounts. Still comfortable with 0.10
to 0.25 inches along the coasts and valleys, with the lowest
totals north of Point Conception. Mountains and foothills are
still expected to see the most, with 0.25 to 0.50 inches. As has
already been noted, locally higher amounts are possible under
thunderstorms. For snow, around 1 to 3 inches can still be
expected above 5500 feet. Snow level will begin to rise as the
cold air moves out.

Decent northerly flow will develop overnight once the low moves
out. There could be some gusty winds through the I-5 corridor and
Santa Barbara South Coast. There will be enough residual moisture
to allow some stratus to form away from the north flow, most
likely the LA County coast and Central Coast. The low clouds will
give way to sunny skies by late morning. Heights will rise to 574
DM and temperatures will rise a few degrees and will come in near
to seasonal normals.

Even more northerly flow is expected Sunday night into Monday
morning, and gusts up to 45 mph can be expected through the I-5
corridor and Santa Barbara South Coast. Back to the dry pattern we
go as a ridge pushes in from the west on Monday. There will be
enough northerly offshore flow to keep low clouds away, but there
is a chance for clouds to cover southern LA County with a weak
eddy developing. Heights will rise even more and temperatures will
jump back a few degrees above normal.

Flow shifts to the northeast on Tuesday as a strong surface high
develops over Wyoming. Advisory level gusts will be possible over
the mountains and valleys prone to Santa Ana winds. The offshore
flow will cause temperatures to rise even more. Some areas over
Ventura and LA County may reach 80 degrees.

.LONG TERM (WED-SAT)...22/250 PM.

High pressure will remain over the area through late week keeping
dry conditions and sunny skies in place. Currently, northeast flow
looks a little stronger on Wednesday than on Tuesday, with the EC
showing it a bit stronger than the GFS. Advisory level gusts over
the mountains and valleys that are susceptible to northeast
winds will be a little more likely than on Tuesday if this is the
case. The offshore flow weakens on Thursday but will still
produce some sub advisory gusts. With rising heights and offshore
flow, it will be warm across the board. Max temps will end up 5
to 10 degrees above normal and some valleys may reach or exceed
80 degrees!

The ridge won`t last too long as a trough starts to dip southward
into the Pacific Northwest over the weekend. Cloud cover will
increase and temperatures will drop into the low to mid 70s over
the coasts and valleys on Saturday.

&&

.AVIATION...23/0008Z.

At 2300Z, there was no marine inversion at KLAX.

Low to moderate confidence in the current forecast. MVFR
conditions for the coast and vly airfields are expected to develop
this evening, through around 18Z Sunday. However, the cigs may
occur periodically and timing is low confidence. There is a 20
percent chance of thunderstorms terminals south and east of KSBA
through 02Z. Any thunderstorms would likely produce erratic,
stronger winds and turbulence, and locally heavy SHRA.

KLAX...Low to moderate confidence in the 00Z TAF. Low confidence
in timing of MVFR cigs overnight. There is also a 20 percent
chance of thunderstorms with the potential for lightning heavy
showers through about 02Z.

KBUR...Low to moderate confidence in the 00Z TAF. Low confidence
in timing of MVFR cigs overnight. There is also a 20 percent
chance of thunderstorms with the potential for lightning heavy
showers through about 02Z.

&&

.MARINE...22/116 PM.

For the Outer Waters, moderate to high confidence in the current
forecast. There is 70%-80% chance of Small Craft Advisory (SCA)
level NW winds tonight through Monday night, and a 50% chance of
SCA level gusts at times around Point Conception on Tuesday. There
is also a 40%-50% chance of Gale force winds at times Sun night
for the southern coastal waters (PZZ676) and a Gale Watch has been
issued. Winds and seas should then be below SCA levels Wednesday
and Thursday.

For the inner waters north of Point Sal, moderate to high
confidence in the current forecast. There is a 50%-60% chance of
SCA level winds at times Sunday and Sunday evening. Otherwise,
winds and seas are forecast to remain largely below SCA levels
through Thursday.

For the Inner Waters south of Point Conception, moderate to high
confidence in the current forecast. There is a 30% chance of SCA
level wind gusts at times for the western Santa Barbara Channel
tonight through Sunday evening. Otherwise, winds and seas are
forecast to remain below SCA levels through Thursday. There will
also be a 20%-30% chance of SCA level NE wind gusts at times near
shore from Point Mugu to Santa Monica later Monday night and
Tuesday morning.

In the short term through sunset today, there is a slight chance
of thunderstorms over the waters, mainly SE of the Channel
Islands. Isolated thunderstorms that develop could bring the
potential for locally gusty winds, choppy seas, small hail, and
dangerous cloud-to-ocean lightning. Conditions will also be
favorable for the formation of short-lived waterspouts.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect from 3 AM Sunday to 9 AM PST
      Tuesday for zones 34-35. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 3 AM PST Tuesday for
      zones 670-673. (See LAXMWWLOX).
     Small Craft Advisory in effect from 9 PM this evening to 6 PM
      PST Sunday for zone 676. (See LAXMWWLOX).
     Gale Watch in effect from Sunday evening through late Sunday
      night for zone 676. (See LAXMWWLOX).

&&

.HAZARD POTENTIAL OUTLOOK (TUE-SAT).

There is a chance of gusty northeast winds Tuesday through
Wednesday.

&&

$$

PUBLIC...Stewart
AVIATION...Smith
MARINE...Sirard
SYNOPSIS...Smith

weather.gov/losangeles