297
FXUS66 KHNX 121103
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
303 AM PST Wed Feb 12 2025

.KEY MESSAGES...

1. A weak system will drop southward over the West Side Hills
and western San Joaquin Valley this morning and into southern
California by this afternoon bringing chances of light
precipitation from Fresno County southward through this
afternoon.

2. A strong storm system will steer an Atmospheric River into
central California on Thursday with periods of moderate to heavy
precipitation. A Flood Watch is in effect for the Sierra Nevada
foothills and down to including the Lake Isabella area from 1000
PM PST this evening to 1000 PM PST Friday. A Winter Storm
Warning is in effect for the Sierra Nevada from 1000 PM PST this
evening to 1000 PM PST Friday.

3. Drier conditions will prevail from Saturday through the
middle of next week as high pressure strengthens off the
California coast on Saturday then moves inland on Sunday.

&&

.DISCUSSION...Satellite imagery showing a shortwave system
dropping southward along the CA coast which has brought some
light precipitation to the West Side Hills and western portion
of the San Joaquin Valley. Some light rain and snow has been
observed along Interstate 5 near Lebec this morning as well with
the snow not sticking at this time. HRRR is indicating that the
snow level will increase from around 4000 feet to above 6000
feet by later this morning as light precipitation continues as
the low drops further southward. This system will bring light
precipitation from Fresno County southward today with QPF progs
showing between one and two tenths of an inch of liquid
precipitation for the Tehachapi Mountains and up to a tenth of
an inch of liquid precipitation elsewhere.

The aforementioned system will then be followed by a much
stronger system tonight as a large low pressure system centered
near 42N/148W continues it`s rapid eastward progression towards
the Norcal coast. Integrated Water Vapor Transport progs from
both the GFS and ECMWF are showing a strong atmospheric river
being pulled through central CA by this low as it nears the
Norcal coast which will bring a period of moderate to heavy
precipitation to much of our area between 09Z Thu and 00Z Fri.
During much of this time frame, snow levels are expected to be
between 7000 and 8000 feet with heavy snowfall above 7000 to
8000 feet in the Sierra Nevada where a Winter Storm Warning
remains in effect between 1000 PM PST this evening and 1000 PM
PST Friday evening as showery precipitation continues across
our area between Thursday evening and Friday evening. The PoE
for 2 inches of liquid precipitation between 1000 PM PST this
evening and 1000 PM PST Thursday evening is between 90 and 1000
percent for the higher elevations of the Sierra Nevada and
between 60 and 90 percent for the adjacent foothills. The PoE
for an inch or more of liquid precipitation for the San Joaquin
Valley and West Side Hills is between 60 and 90 percent and for
the Kern County Deserts between 45 and 75 percent during this
same time frame. With widespread moderate to have precipitation
expected, the Weather Prediction Center has the Sierra
Foothills and much of the San Joaquin Valley east of SR 99 in a
slight risk (15-39%) for excessive rainfall leading to rapid
onset flooding on Thursday. A Flood Watch remains in effect for
the Sierra Foothills, Kern River Valley and Piute Walker Basin
areas from 1000 PM PST this evening to 1000 PM PST Friday.

Following the passage of the moist atmospheric river system on
Thursday, the low will push eastward in to the Great Basin on
Thursday night and pull down additional moisture as well as
some cooler air aloft into our area Thursday night and Friday.
This will result in chances for thunderstorms for much of the
San Joaquin Valley and Sierra Foothills on Thursday night and
Friday. WRF is indicating LI`s between -1 and 1 DEG C and CAPES
between 100 and 400 J/KG across much of the San Joaquin Valley
midday Friday. With the cooler air moving in on Friday, snow
levels will lower to 5000 to 5500 feet by the time the showers
taper off on Friday evening.

The medium range ensembles are in fairly good agreement with an
upper ridge strengthening off thew CA coast on Saturday then
shifting inland on Sunday. A weak inside slider type system
will drop southward ahead of the ridge and bring a slight chance
of showers to the Sierra Nevada on Sunday and Monday before
another ridge strengthens off the coast on Tuesday bringing
drier weather to our area. Temperatures will be slightly above
normal for the weekend into the early portion of next week.

&&

.AVIATION...12Z:

In the San Joaquin Valley and West Side Hills, VFR conditions
with medium level ceilings until 06Z Thu. Increasing areas of
MVFR in rain, mist and low clouds after 06Z Thu.

In the Sierra Nevada, adjacent foothills and Tehachapi
Mountains, mainly VFR conditions with areas of MVFR in low
clouds and showers thru 06Z Thu then mountain obscuring IFR in
low clouds and precipitation becoming widespread between 06Z Thu
and 09Z Thu and becoming prevalent by 12Z Thu.

In the Kern County portion of the Mojave Desert, VFR conditions
thru 06Z Thu then increasing areas of MVFR in rain and low
clouds after 06Z Thu.

&&

.AIR QUALITY ISSUES...On Wednesday February 12 2025,
Fireplace/Wood Stove Burning Status is: No Burning Unless
Registered in Fresno and Kern Counties. Burning Discouraged in
Kings, Madera, Merced, and Tulare Counties, and Kern (Greater
Frazier Park Area) and Sequoia National Park and Forest.

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.

Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
and/or to provide feedback.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 4 AM PST early this morning for CAZ338.
Flood Watch from this evening through Friday evening for
CAZ317>322-332-333.
Winter Storm Warning from 10 PM this evening to 10 PM PST
Friday for CAZ323-326>331.

&&

$$

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