313
FXUS66 KHNX 231816
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
1116 AM PDT Mon Sep 23 2024


&&

.KEY MESSAGES...

1. A warming trend will continue across the region with a
moderate to high probability (30 to 75 percent) of temperatures
reaching triple digits in the San Joaquin Valley on Tuesday.

2. A cooling trend will take place on Wednesday and Thursday,
but temperatures will remain above normal for the rest of the
week and into the weekend.

3. A dry week for the region is expected for all of the interior
of central California. Relative humidity values are expected to
fall into the single digits during the afternoon hours for
eastern Kern COunty. The rest of the area`s relative humidity
values will fall into the low 20s. Overnight recoveries will be
poor for the desert and higher elevations while moderate for the
valley.

&&

.DISCUSSION...

A cut-off upper level low centered off the California coast has
split from a longwave upper level trough moving through the
central United States this morning. Cyclonic flow around this
low pressure system will gradually shift winds over central
California to the east to southeast during Monday. The
directional shear between the cut-off low and the main trough is
expected to stagnate winds aloft over the region which, when
combined with daytime heating, will result in warmer conditions,
continuing the warming trend from the weekend. Moving into
tomorrow, an upper level area of high pressure will slide into
the Great Basin region along the northern side of the
aforementioned cut-off low. The increasing pressure aloft along
with wind shifting to the south to southwest will warm
temperatures even further, with tomorrow being the warmest day
of the week.

Afternoon temperatures today are expected to be five to ten
degrees above season normals through the San Joaquin Valley,
Kern County Desert, and Sierra Nevada Foothills. With
temperatures on Tuesday having the potential to reach up to
thirteen degrees above average in the valley areas.

There is less than a 20 percent chance for afternoon
temperatures to exceed 100 degrees this afternoon, however the
following are probabilities to reach triple digits Tuesday
afternoon.

Bakersfield 65%
Coalinga     5%
Fresno      65%
Hanford     75%
Madera      30%
Merced      50%
Visalia     30%

While triple digits are conceivable, temperatures above 95
degrees are much more likely, and as such the following are the
chances to reach or exceed these temperatures through the middle
of the week.

                Monday    Tuesday    Wednesday   Thursday
Bakersfield       85%       100%        65%         10%
Coalinga          75%        99%        15%          3%
Fresno            85%       100%        45%         15%
Hanford           90%       100%        75%         25%
Madera            75%        99%        20%          5%
Merced            80%        99%        20%         10%
Visalia           75%        99%        45%         15%

The lower probabilities in the middle portion of this week are
primarily due to two factors. First, the aforementioned upper
level high will progress eastward and become further elongated
north to south. Second, a stronger upper level trough is
anticipated to track through the Pacific Northwest region,
ingesting the cut-off low as it approaches. The pressure
gradient between these two upper level systems will increase
winds aloft and shift them to the southwest, breaking the
stagnant pattern from the early week. As such, a slight cooling
trend will set up across central California; however as the
upper level flow will be from the southwest, temperatures will
remain above season averages.

Dry conditions will persist across central California through
the forecast period with relative humidity values hovering
around 20 to 25 percent in the San Joaquin Valley and Sierra
Nevada Foothills and around 10 percent in the Kern County
Desert. While winds across the region are expected to be
relatively light, diurnal, and terrain driven, the lower
humidity values and poor overnight recoveries will continue to
drive the potential for grass fire development.

&&


.AVIATION...VFR conditions will prevail across the central CA
interior over the next 24 hours.

&&

.AIR QUALITY ISSUES...
ISSUED:  09/22/2024 13:52
EXPIRES: 09/23/2024 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.............VJP

weather.gov/hanford