Acton Weather

361
FXUS66 KLOX 210405
AFDLOX

Area Forecast Discussion...UPDATED
National Weather Service Los Angeles/Oxnard CA
905 PM PDT Wed Mar 20 2019

.SYNOPSIS...20/728 PM.

Showers may linger over the area tonight, but otherwise conditions
should stay cloudy and dry. Another system will arrive Thursday
morning bringing a chance of showers and mountain snow. Dry
conditions are expected Friday and another chance for rain is
expected Saturday. Below normal temperatures are expected through
the remainder of the week.

&&

.SHORT TERM (WED-SAT)...20/843 PM.

The latest satellite imagery shows broad troughing over the
region this evening. One shortwave trough is located over
southeastern Kern County and moving east of the area, while an
upstream shortwave trough is located about 200 miles west-
southwest of San Francisco. The upstream trough will dip
into the Mojave Desert and Owens Valley through Thursday
afternoon. Isolated to scattered showers will continue through
this evening, decreasing through the night across the southern
portion. Shower activity with the upstream trough will start to
push into the Central Coast after midnight tonight. The window is
closing for the thunderstorm potential tonight as 500 mb
temperatures are warming this evening. Snow levels have been
lowered a tad down to near 4500 feet. In heavier showers, the snow
level could locally lower to 4000 feet as evaporative cooling
takes place. Small hail cannot be ruled out either in heavier
showers into the valley and coastal areas. Rainfall amounts still
look to be under a quarter of an inch or less, except maybe
locally higher amounts along the northern slopes of the mountains.

***From Previous Discussion***

Dry and warmer Friday as a little ridge develops.

On Saturday another weak system is expected to pass through but
again favoring just northern areas. Most model solutions keep rain
north of Pt Conception and very light.

.LONG TERM (SUN-WED)...20/152 PM.

Sunday another ridge develops with a light offshore gradient so
temps expected to warm up a few degrees.

Another system brewing out over the Pacific is poised to move
onshore along the west coast early next week, but the models are
disagreeing on how strong the ridge ahead of it will be and this has
an impact on how far south the clouds and rain chances will
reach. The GFS is the wetter solution, spreading light rain as far
south as LA County by Wednesday. The ECMWF keeps most of it
mainly north of Pt Conception. Seems prudent given the pattern to
go with at least a slight chance most areas, though again amounts
will be insignificant.

&&

.AVIATION...20/2340Z.

At 23Z, there was no marine layer.

TSRA will be possible through 03Z over Los Angeles County away
from the immediate coast, then moderate confidence that the
convective threat will end. Low confidence in how clouds evolve.
Chance for SHRA again on Thursday, but much less active and
intense as today.

KLAX...Low confidence in TAF. Conds will vary frequently, but
should be mostly MVFR this evening and tonight.

KBUR...Low confidence in TAF. Conds will vary frequently, but
should be mostly MVFR this evening and tonight.

&&

.MARINE...20/859 PM.

Moderate-to-high confidence in the current forecast.

Across the outer waters, winds and seas will likely remain below
Small Craft Advisory levels into Thursday. There is a 30-40
percent chance of Small Craft Advisory level northwest winds
Thursday afternoon and night, and again Friday afternoon and
evening, highest south of Point Conception. The chance for Small
Craft Advisory level northwest winds will increase on Saturday
afternoon and night to between 50-60 percent, along with the
potential for hazardous seas.

For the Inner Waters north of Point Sal, winds and seas will
likely remain below Small Craft Advisory levels into Thursday.
There is a 20-30 percent chance of Small Craft Advisory level
northwest winds Thursday afternoon and night, and again Friday
afternoon and evening. The chance for Small Craft Advisory level
northwest winds will increase on Saturday afternoon and night to
between 40-50 percent, along with the potential for hazardous
seas.

For the Inner Waters south of Pt Conception, there is a 20 percent
chance of Small Craft advisory winds this evening, otherwise
winds and seas will likely remain below Small Craft Advisory
levels into Thursday. There is a 30-40 percent chance of Small
Craft Advisory level northwest winds each afternoon and night
through Saturday afternoon and night.

&&

.BEACHES...20/904 PM.

A relatively large, long period west-northwest swell will slowly
subside this evening and into Thursday. Another long period west-
northwest swell could bring high surf to area beaches again
Saturday and Sunday.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory in effect until 11 PM PDT this evening for
      zones 34-35. (See LAXCFWLOX).
     High Surf Advisory in effect until 3 PM PDT Thursday for
      zones 40-41-87. (See LAXCFWLOX).
PZ...NONE.

&&

.HAZARD POTENTIAL OUTLOOK (SAT-WED).

High surf and dangerous rip currents are expected over the
weekend.

&&

$$

PUBLIC...Hall/MW
AVIATION...RK
MARINE...Hall
BEACHES...Hall
SYNOPSIS...Stewart

weather.gov/losangeles