692
FXUS66 KHNX 121204
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
504 AM PDT Wed Mar 12 2025


.KEY MESSAGES...

1. An Atmospheric River storm system will bring significant
precipitation for all of interior Central California from late
this afternoon through Thursday evening.

2. A Winter Storm Warning is in effect for the Sierra Nevada
due to heavy snowfall and a Winter Weather Advisory is in effect
for the Lower Sierra Nevada and for the Kern County Mountains,
including the Grapevine.

3. A High Wind Warning is in effect for the West Side Hills and
a the Mojave Desert Slopes. A Wind Advisory is in effect for the
western San Joaquin Valley and the Kern County Desert.

4. Moderate to heavy rainfall is expected for the Sierra Nevada
Foothills during the course of this system and moderate rainfall
is expected across portions of the San Joaquin Valley.

5. There is a slight chance for thunderstorms on Thursday with
potential for locally heavy rainfall, small hail, strong wind
gusts, and frequent lightning.

&&

.DISCUSSION...
A deepening upper trough approaching the west coast will steer a
strong atmospheric river into central California this afternoon
through Thursday. Significant impacts are expected from this
system with periods of moderate to heavy precipitation, strong
gusty winds, and lowering snow levels. Light precipitation will
begin later this morning across the higher terrain and gradually
increase in coverage this afternoon. The bulk of precipitation
will occur from this evening through Thursday morning. Scattered
showers will continue through Thursday along with a slight chance
for thunderstorms.

Rainfall across the San Joaquin Valley is expected to generally
range from 0.25" to 0.75" with the lower amounts favored across
the western side of the valley due to rain shadowing. Localized
amounts in excess of 1" are conceivable, especially around any
thunderstorms. Rainfall from 1 to 3 inches is forecast across
the Sierra Nevada foothills, prompting a marginal risk (5-14%)
of rainfall exceeding flash flood guidance. Burn scar areas will
be closely watched for debris flow potential with thunderstorms
raising concern for producing higher rainfall rates.

Snow levels will begin around 6000 feet today then lowering to
around 3000 feet by Thursday morning. A Winter Storm Warning is
in effect for the Sierra Nevada with 1 to 3 feet expected above
4000 feet and up to 4 feet across the highest elevations. Snow
amounts from 6 to 12 inches is forecast from 3000 to 4000 feet
across the lower Sierra where a Winter Weather Advisory is in
effect. There is also a Winter Weather Advisory for the Kern
County mountains with 2 to 6 inches above 4000 feet and up to 15
inches across the highest elevations. There is a 45% probability
for 2 inches of snow along Tejon Pass a 58% chance for 4 inches
of snow along Tehachapi Pass.

Strong gusty winds will develop today with a High Wind Warning
for the West Side Hills and Wind Advisory for the western side
of the San Joaquin Valley. A High Wind Warning is in effect for
the Mojave Desert Slopes today through Friday afternoon along
with a Wind Advisory for the Kern County desert during the same
time frame.

Precipitation tapers off Thursday evening. Cold air is in place
behind it as a weaker system quickly moves in on Friday morning.
Light snowfall is possible across the West Side Hills and Sierra
Foothills with the snow level possibly down to 2000 feet Friday
morning. Most of the precipitation is expected Friday afternoon
with it tapering off in the evening. Dry weather Saturday then
another system arrives Sunday evening through Tuesday morning.

&&

.AVIATION...
For the Sierra Nevada, adjacent foothills and Tehachapi Mountains,
areas of MVFR and local mountain obscuring IFR in low clouds and
showers after 12z Wednesday. Becoming widespread mountain obscuring
IFR between 12z and 18z Wednesday, continuing through 12z Thursday.

For the San Joaquin Valley and West Side Hills, VFR through 00z
Thursday. Increasing areas of MVFR in low clouds and rain after
00z Thursday with an 80-90 percent probability of MVFR after 06z
Thursday.

For the Kern County portion of the Mojave Desert, Probability of
surface winds gusting above 35 knots at 70-90 percent after 00z
Thursday. Areas of MVFR in low clouds and rain after 06z Thursday.

&&

.AIR QUALITY ISSUES...
None.

&&

.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...
High Wind Warning from 11 AM this morning to 5 PM PDT Friday
for CAZ338.
Wind Advisory from 11 AM this morning to 5 PM PDT Friday for
CAZ337-339.
High Wind Warning from 8 AM this morning to 8 AM PDT Thursday
for CAZ300-304-308-313.
Wind Advisory from 8 AM this morning to 8 AM PDT Thursday for
CAZ301-305-309.
Winter Weather Advisory until 11 PM PDT Thursday for CAZ318-
320-322.
Winter Storm Warning until 11 PM PDT Thursday for CAZ323>331.
Winter Weather Advisory from 5 PM this afternoon to 5 AM PDT
Friday for CAZ333>336.

&&

$$

DCH

weather.gov/hanford