589
FXUS66 KHNX 301821
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
1121 AM PDT Wed Jul 30 2025


&&

.KEY MESSAGES...
1. There is a 10 to 30 percent chance for showers and
thunderstorms to develop across the Sierra Nevada crest this
afternoon, with the greatest chances in the high country of
Yosemite National Park.

2. Temperatures continue to climb to near season averages, with
an increase in fire risk due to lowering RH values and breezy
conditions.

&&

.DISCUSSION...
The current synoptic pattern remains relatively unchanged today,
with an upper level trough presently located to the west over
the Pacific and an area of high pressure located over the
south-central US. However, a smaller disturbance within the
trough is in the process of tracking through central California,
causing convective initiation along the northern Sierra range
outside of our county warning area. As the day progresses,
warmer upsloping winds from the San Joaquin Valley will tap into
the mid level moisture resulting from the perturbation and
cause a more favorable chance for showers and thunderstorms
along the central Sierra crest compared to the previous few
days, but with the greatest chances in the high country of
Yosemite National Park; chances for this afternoon are 10 to 30
percent.

For the latter portion of this week, the aforementioned are of
high pressure will build into the Desert Southwest, directing
atmospheric flow from due west, resulting a zonal flow pattern.
Temperatures over the region are expected near season averages
as this pattern typically results in seasonal conditions.
Afternoon highs for the valley areas will continue to be in the
upper 90s, hitting a peak on Friday and Saturday before cooling
slightly into early next week. There is a 20 to 40 percent
chance for locations south of Fresno to exceed 100 degrees both
days. The increase in temperatures will correspond with a
decrease in relative humidity, which may cause more widespread
fire concerns. Breezy downsloping winds in the western San
Joaquin Valley and Mojave Desert Slopes, and upsloping winds in
the Lake Isabella area will also contribute to these concerns;
however, fire risk remains at levels typical for late July.

As stated, a cooler start to next week is in the cards due to a
shortwave upper level trough making its way through northern
California Monday before high pressure begins to build for the
middle of next week. As for now, forecast guidance places a 50
to 75 percent chance for afternoon highs to exceed 100 degrees
next Wednesday through Friday in the San Joaquin Valley as a
result of the subsiding air associated with the high.


&&


.AVIATION...
18Z Update:

VFR conditions are expected in the San Joaquin Valley for the next
24 hours. A 10 to 30 percent chance of thunderstorms will exist
across the Sierra Nevada Crest from Yosemite to Tulare County
through 03Z Thursday.

&&

.AIR QUALITY ISSUES...
ISSUED:  07/29/2025 14:13
EXPIRES: 07/30/2025 23:59
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...
None.
&&

$$

public/aviation...McCoy

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