094
FXUS66 KHNX 142030
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
130 PM PDT Sun Jul 14 2024

.KEY MESSAGES...

1. The Red Flag Warning will be in effect through 9 PM this
evening for the Sierra Nevada through the northern Kern County
mountains for dry thunderstorms which can cause gusty winds and
fire starts.

2. A 15-30% chance of thunderstorms in the high elevations
through this evening can produce dry lightning with a less than
10% chance of wetting rain.

3. The high risk of grass fires in the valley continues, with
fire behavior enhanced even with low wind speeds.

4. HeatRisk will mainly be in the moderate category across the
lower elevations for much of the week but once again rise back
into the high category next weekend.

&&

.DISCUSSION...The large upper ridge that has been responsible
for the persistent heat wave across our area for the previous
12 days has shifted eastward into CO and NM as a shortwave
trough off the CA coast has deepened some. The main impact from
this has been lowering heights and thicknesses across our area
resulting in a noticable cooling trend with most locations in
our CWFA running 3 to 6 DEG F below yday at this time. With
temepratures expected to continue trending downward on Monday
and Tuesday as the offshore shortwave meanders off the Norcal
coast, the HeatRisk for lower elevations will mainly be in the
moderate category although temperatures will remain slightly
above normal. With temperatures expected to remain below
dangerous heat levels, have expired the Excessive Heat Warning
which had been in place across much of our area for the previous
12 days.

Besides the ongoing cooling trend, the other weather concern at
this time is upper level tropical moisture streaming northward
into CA from the south. While the coverage of clouds across our
area is much less than yday (when we had a more favorable
southeast flow aloft), radar composites are showing scattered
showers and thunderstorms have developed again over the Sierra
Nevada (mainly near the crest) and even a few further southward
over the Tehachapi Mountains. AWIPS lightning displays showing
some strikes over the Sierra Nevada and with the lower and mid
levels still fairly dry, some dry lightning is not out of the
question through this evening so a Red Flag Warning remains in
effect for the Sierra Nevada through the northern Kern County
mountains through 900 PM PDT this evening.

Temperatures are expected to bottom out on Wednesday with
probabilistic guidance indicating a PoE of 100 DEG F in the San
Joaquin Valley of 20 percent or less at most locations.
However, most of the medium range ensemble members are showing
the ridge to our east will build back westward and strengthen
over AZ and UT late in the week. This will result in rising
heights and thicknesses across our area between Thursday and
next weekend. The PoE of 105 DEG F across the San Joaquin Valley
will increase to 30 to 60 percent across most of the San
Joaquin Valley by next weekend with the HeatRisk rising back
into the high to extreme categories suggesting heat highlights
might be needed as next weekend approaches. In addition, RH
progs are showing another surge of tropcial moisture being
pulled up behind the ridge and spreading into our area next
weekend which will provide for at least a slight chance of
thunderstorms for the Sierra Nevada on Saturday and Sunday.

&&

.AVIATION...Areas of MVFR and local mountain obscuring IFR in
showers and thunderstorms over the Sierra Nevada through 04Z
Mon. Areas of MVFR and local IFR visibility will continue in
and around wildfires. Otherwise, VFR conditions will prevail
across the central CA interior until further notice.

&&

.FIRE WEATHER...A Red Flag Warning remains in effect for the
Sierra Nevada mountains through 9 PM this evening due to an
increased probability of dry lightning from thunderstorms
(15-30%). These storms have less than a 10% chance of producing
wetting rain, which would lead to a high risk for new fire
starts in the area, in addition to the dry fuels and low
humidity.

&&

.AIR QUALITY ISSUES...None.

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is medium.
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...
Red Flag Warning until 9 PM PDT this evening for CAZ592>595.

&&

$$

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