826
FXUS66 KHNX 190447
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
946 PM PDT Fri Jul 18 2025

.UPDATE...Updated Aviation section.

&&

.KEY MESSAGES...

1. Showers and thunderstorms developing across the Sierra
Nevada Crest with a 10 to 30 percent chance Today and Tomorrow,
especially for Tulare county.

2. Gusty outflow winds across the eastern Kern County deserts
may lead to low visibilities because of dust,associated with
thunderstorms in western San Bernardino county.

3. Probability of greater than 0.10" of rain is 30%-50% in the
high Sierra of Fresno and Tulare counties today and tomorrow,
thus some dry lightning strikes will occur.

4. Nocturnal thunderstorms can occur in this weather pattern,
not just reserved to afternoon and evening.

5. Long string of cooler temperatures and breezy conditions
for the middle of next week, with some fire weather concerns.

&&

.DISCUSSION...
Moisture will reach a maximum over the next 48 hours across the
high Sierra and eastern Kern, from the disturbance near Baja
California. Upslope flow along the high Sierra in combination
with the elevated instability will also contribute to showers
and thunderstorms today through tomorrow. For several runs, hi
res near term models have focused thunderstorms in the high
Sierra of Tulare County, but the overall atmospheric profile
suggests that showers and thunderstorms, in the most extreme
case, will stretch from south to north along the Sierra Crest
and through the Kern County Mountains and Deserts with a 10%-30%
probability.

This monsoonal setup suggests that showers and thunderstorms are
possible well after midnight and into the morning hours, with
instability remaining aloft due to the incoming moisture, late
Friday night through late Saturday night.

Although the chance of 30 mph wind gusts is only 30% in the
eastern Kern Deserts, still need to keep am eye on the complex
of showers and storms currently in San Bernardino county. Best
case, nothing arrives across the Kern county border. Worst case,
outflow from this complex speeds west and leads to low
visibilities because of dust being kicked up by the wind. In
addition, some thunderstorms may sneak into Kern County, which
may be close to the sensitive Borel Burn Scar and the currently
burning Kay Fire, which would lead to erratic changes in wind
direction and speed which are very dangerous for the firefighter
on scene. Again although some of these outcomes are worst
case/low probability, they still deserve our attention.

Any thunderstorms producing less than a tenth of an inch of
rain, or lightning strikes far from the center of any storm,
can contribute to fire starts also.

As the Baja Low disappears, our moisture flow is cut off,
leading to a dry Sunday with temperatures hotter. After a
respite of 100F, the probability of high temepratures reaching
that mark climbs to 40% for Fresno to Bakersfield and points
just east of I-5 on Sunday.

However, any chances of a heat wave are quickly thwarted by
another building trough along the entire west coast into
midweek. This scenario has happened many times this summer, but
becomes more and more unusual into mid July. 100F Probabilities
disappear, and cities like Merced in the north valley may not
even reach 90F (60%-80% Probability) next Tuesday and Wednesday.

But, with the arrival of cooler air comes gusty winds for this
time of year, with 50%-70% Probabilities of Wind Gusts of 25 mph
or more for the valley floor, even Fresno, Tuesday and
Wednesday. Best outcomes would be temperatures near 90F with an
unusually persistent July breeze, worst case scenario would be
that drier air along with gusty winds contributes to increased
fire danger and spread potential.

Cluster and ensemble guidance largely agree in the depiction of
west coast troughing, but disagree with regards to its strength.
The most extreme solutions close off an area of Low pressure
aloft which would be the breeziest and cooler solution, although
that is not expected.

Into next weekend, cluster and ensemble guidance lifts the
trough away to varying amounts, with ridging over the four
corners region oozing west, leading to increasing temperatures
and slightly increased probabilities for mountain
thunderstorms.

&&

.AVIATION...06Z Update:
There is a low (5-10%) chance of overnight thunderstorms
tonight in the mountains and desert. Otherwise, expect
isolated thunderstorms to develop (15-25% chance) in the
higher elevations of the Sierra Nevada from 18Z Saturday
until 06Z Sunday with generally MVFR conditions.
Elsewhere, expect VFR conditions and mainly light winds
over the next 24 hours.

&&

.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 high.

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...
None.
&&

$$

public...Mattarochia
aviation....BSO

weather.gov/hanford