418
FXUS66 KHNX 130810
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
110 AM PDT Mon Oct 13 2025


&&

.KEY MESSAGES...
1. Winter Storm Warning in effect from 11 AM Monday through 5 PM
Wednesday.

2. Flood Watch in effect from 5 PM Monday through 5 PM Tuesday
for the Sierra Nevada foothills.

3. Portions of the Sierra Foothills and the Valley is under a
Marginal (5-15 percent) Risk of Excessive Rainfall Monday and
Tuesday.

4. There is a 5 to 30 percent chance of at least 18 inches of
snow between 6,000 and 7,000 feet and a 60 to 85 percent chance
of at least 18 inches of snow above 7,500 feet through 5 PM
Wednesday.

5. The San Joaquin Valley has a 35 to 75 percent chance of at
least an inch of rain in 24 hours ending Tuesday at 5 PM. The
Sierra foothills have a 25 to 65 percent chance of at least 2
inches of rain in 24 hours ending at 5 PM Tuesday.

6. Drier and calmer conditions will prevail Thursday into the
weekend before another trough slides in next Monday.

&&

.DISCUSSION...
Satellite imagery this morning has the trough sliding in from
the Pacific Northwest with an outer band moving through at about
1 in the morning Pacific time. Latest model ensembles have shown
this trough to be deeper than the one from last week. In
addition, the latest ensembles are in strong agreement of a near
90 percent chance of Integrated Water Vapor Transport values of
at least 250 kg/(m*s). In addition, temperatures will continue
to drop with this storm which will lower snow levels to about
5,500 to 6,000 feet.

This combination of high moisture values and cold temperatures
have led models to have a 5 to 30 percent chance of at least 18
inches of snow between 6,000 and 7,000 feet and a 60 to 85
percent chance of at least 18 inches of snow above 7,500 feet
through 5 PM Wednesday. Thus, we have a Winter Storm Warning in
effect from 11 AM this morning through 5 PM Wednesday. There
also is a 6 percent chance of a trace of snow along Interstate 5
through Tejon Pass through Wednesday evening.

In the Valley, we are looking at a 35 to 75 percent chance of
at least an inch of rain in 24 hours ending Tuesday at 5 PM.
But, a Flood Watch is in effect for the foothills from 5 PM
Monday through 5 PM Tuesday as there is a 25 to 65 percent
chance of at least 2 inches of rain in 24 hours ending at 5 PM
Tuesday. The major concern with the rain is the resulting
flooding and debris flows at the burn scars.

As the trough moves away late Wednesday into Thursday, a small
ridge begins to build to the west. This ridge will gradually
slide into the area over the weekend bringing temperatures back
up. However, model ensembles agree another trough will slide in
on Monday of next week.

&&


.AVIATION...
VFR conditions are expected to prevail until 21Z Monday. After
21Z, MVFR to IFR conditions begin to appear in the mountains in
showers and low clouds, while the Valley could also see lower
visibilities in heavier showers. There is a 5 to 20 percent
chance of thunderstorms beginning at 0Z Tuesday for the Valley
and Sierra Nevada through 0Z Wednesday.

&&

.AIR QUALITY ISSUES...
None.

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is high.
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...
Flood Watch from this afternoon through Tuesday afternoon for
CAZ318-320-322-324-325-332-333.
Winter Storm Warning from 11 AM this morning to 5 PM PDT
Wednesday for CAZ323-326>331.
&&

$$

JPK

weather.gov/hanford