548
FXUS66 KHNX 301121
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
421 AM PDT Sun Jun 30 2024


&&

.KEY MESSAGES...

1. Warming continues this weekend before a dangerous, long-
duration heat wave hits the central valley of California through
the holiday week and into next weekend.

2. An Excessive Heat Warning has been issued for Tuesday July
2nd through Monday July 8th.

3. The risk of grass fires will continue to increase with
herbaceous fuel loading at or near 120% of normal. A long period
of excessive heat, minimum relative humidities near 15%, and
poor overnight relative humidity recoveries may require a Fire
Weather Watch as the event nears.

&&

.DISCUSSION...

Triple digit heat returned to the San Joaquin Valley yesterday
afternoon as upper level flow shifted to the southwest ahead of
a trough that is projected to move through the Pacific Northwest
region later today. With the center axis of the trough passing
over central California this afternoon, winds aloft will have a
brief shift to west-east, or zonal, flow. As a result, there
will be a slight cooldown today by a degree or two. However,
maximum temperatures will still be around 3 to 6 degrees above
normal for this time of the year. High resolution ensemble
guidance from the HREF suggests a moderate to high probability
(50 to 80 percent) for temperatures to exceed 100 degrees this
afternoon, however probabilities drop to less than 30 percent to
exceed 102 degrees for most of the San Joaquin Valley; the
ensemble expresses a 50 percent chance for Bakersfield.

While temperatures are projected to be warmer than average on
Sunday, they will also be the coolest of the week. On Monday, an
upper level ridge will begin to build over the western United
States as a result of the exiting trough. The stagnant,
subsiding air aloft will trap heat closer to the surface,
warming temperatures each day through Wednesday, at which point
temperatures are expected to stabilize between 105 and 110
degrees. The following are probabilities from the National Blend
of Models to reach or exceed 105 each day through next Saturday
in the San Joaquin Valley.

    Mon    Tue    Wed    Thu    Fri    Sat
Merced       0%    31%    91%    71%    51%    56%
Madera       0%    21%    86%    71%    51%    56%
Fresno       2%    51%    96%    91%    71%    71%
Reedley      0%    11%    76%    61%    26%    46%
Lemoore      0%    41%    96%    91%    61%    66%
Hanford     0%    31%    91%    81%    61%    61%
Visalia      2%    41%    96%    86%    61%    66%
Porterville  2%    41%    96%    81%    51%    66%
Delano       2%    41%    96%    81%    61%    71%
Bakersfield  2%    41%    96%    76%    51%    66%



The following are probabilities to reach or exceed 110 each day
through next Saturday in the San Joaquin Valley.

    Mon    Tue    Wed    Thu    Fri    Sat
Merced       0%     0%    26%     6%     6%    16%
Madera       0%     0%    11%     6%     6%    16%
Fresno       0%     0%    51%    31%    11%    36%
Reedley      0%     0%     2%     6%     6%     6%
Lemoore      0%     0%    31%    11%    11%    21%
Hanford     0%     0%    31%    11%     6%    21%
Visalia      0%     0%    41%    21%    11%    21%
Porterville  0%     0%    41%    16%     6%    21%
Delano       0%     0%    41%    21%    11%    31%
Bakersfield  0%     2%    41%    16%     6%    31%

The aforementioned upper level ridge is anticipated to remain
stationary over California throughout the next week, continuing
the above normal temperatures across the region. While the
maximum temperatures each day are a concern, rising morning lows
will provide little relief from the daily heat, especially in
the larger cities where the influence of the urban heat islands
take effect. There is a 80 to 95 percent probability for low
temperatures to exceed 75 degrees in Bakersfield and Fresno each
morning from Wednesday, July 3rd through Saturday, July 6th;
there is a 10 to 40 percent probability for the other areas of
the valley. However, there is a 50 to 80 percent probability to
reach or exceed 70 degrees each morning for these other
locations. As a result of these poor overnight recoveries, Major
to Extreme Heat Risk impacts will be present in the San Joaquin
Valley from Wednesday through Sunday.

&&


.AVIATION...
Continued areas of MVFR and local IFR visibility due to smoke
nearby the Fresno County fires will continue in the Sierra
Nevada and adjacent foothills. Otherwise, VFR conditions will
prevail across the central California interior for the next 24
hours.

&&

.FIRE WEATHER...

Fuel moistures are typically at their lowest and Energy Release
Component typically the highest from late June through July.
Near record low 100 hour and 1000 hour fuel moisture are
forecast to occur during the heat wave next week, especially in
the Central Valley. Additionally, ERC is forecast to approach
record highs. This will create an increased risk for grass
fires, especially on the 4th of July.

&&

.AIR QUALITY ISSUES...

Air Quality Alert due to smoke impacts from wildfires.

&&

.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...
Excessive Heat Warning from 11 AM Tuesday to 8 AM PDT Monday
for CAZ300>322-324-332-334-336>339.
&&

$$

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