374
FXUS66 KHNX 080926
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
226 AM PDT Sun Sep 8 2024


&&

.KEY MESSAGES...
1. A cooling trend will start today across central California as
an upper level high pressure system begins to weaken over the
next few days. Afternoon temperatures will remain above normal
through Tuesday.

2. There is a 10 to 15 percent chance for isolated showers and
thunderstorms over the Kern County Mountains and Desert this
afternoon and evening due to monsoonal moisture entraining over
the region.

3. Low daytime humidity and poor overnight recovery will
provide for an elevated risk of grass fires in eastern Kern
County and over the West Side Hills through early next week.

4. An upper level trough is projected to drop southward into the
western United States midweek, bringing about near normal
temperatures to central California. There is an 80 to 90 percent
chance for afternoon highs to remain below 90 degrees in the San
Joaquin Valley Thursday.

&&

.DISCUSSION...

An upper level area of high pressure continues to remain
dormant over the southwestern United States this morning. A
gradual weakening of the ridge over the next few days will bring
a light cooling trend to central California into the early part
of this week. However, temperatures through Tuesday are
projected to prevail above season averages for this time of
year. The following are probabilities from the National Blend of
Models for temperatures to reach or exceed 100 degrees in the
San Joaquin Valley through Tuesday.

              Sunday      Monday     Tuesday
Bakersfield    70%         80%         45%
Coalinga       70%         60%         10%
Fresno         90%         85%         30%
Hanford        95%         95%         35%
Madera         85%         85%         10%
Merced         60%         60%          4%
Visalia        80%         75%         20%

While continuing the warmer temperatures across the region, the
anticyclonic flow around the center of the high will entrain
increased monsoonal moisture from the Pacific over southern
California, including eastern Kern County, this afternoon.
Triple digit highs in the Mojave Desert will contribute to
increased convective potential for the region. However, high
resolution ensemble guidance from the HREF shows only a 10 to 20
percent probability for localized areas of measurable rainfall
greater than 0.01 inches.

Drier conditions are anticipated for Monday and Tuesday as the
aforementioned upper level high weakens, and an upper level
trough begins to deepen into the western United States from the
Gulf of Alaska. Cyclonic flow around this system is projected to
drop temperatures near normal for this time of year midweek as
cooler air approaches the region from the northwest. Maximum
temperatures Wednesday will be around six to eight degrees less
than those on Tuesday afternoon, with further drop by two to
five degrees between Wednesday and Thursday. The following are
probabilities for temperature to reach or exceed 90 degrees in
the San Joaquin Valley Wednesday through Friday.

              Wednesday     Thursday       Friday
Bakersfield      60%           10%          45%
Coalinga         25%           10%          30%
Fresno           50%           15%          50%
Hanford          80%           20%          75%
Madera           35%           20%          60%
Merced           25%           15%          55%
Visalia          65%           15%          55%

The long term synoptic pattern shows a return to zonal flow on
Friday and Saturday, bringing about near-normal temperatures to
the region entering next weekend. However, cluster analysis is
showing a favorable trend towards another upper level trough
dropping south from the Gulf of Alaska next Sunday into Monday.
This pattern would cause temperatures to decrease once again
across the San Joaquin Valley, with highs potentially falling
below average for the first time since late August.

&&


.AVIATION...
Areas of MVFR and local IFR visibilities near wildfires.
Otherwise, VFR conditions will prevail across the central CA
interior over the next 24 hours.

&&

.AIR QUALITY ISSUES...
ISSUED:  09/07/2024 14:32
EXPIRES: 09/08/2024 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...SM
IDSS.............BSO

weather.gov/hanford