Wildfire in California, August 19 to 31, 2020

Area Forecast Discussion
National Weather Service Hanford CA
413 AM PDT Wed Aug 19 2020

.SYNOPSIS...Another dangerously hot day is expected across the
region. We'll also have the chance of thunderstorms over the
higher elevations of the Sierra, and a slight chance of thunder
over the far eastern portion of the Kern County desert.
Temperatures will cool down into the weekend, but will remain
above average.

&&

.DISCUSSION...We all get to enjoy yet another dangerously hot day
across the central California interior as our current heat wave
continues...Yay!! Afternoon temperatures will be similar to
Tuesday, with highs between 104 to 109 degrees in the Southern San
Joaquin Valley and West Side Hills. Temperatures in the Sierra
foothills will end up between 98 to 103 degrees. Finally,
temperatures in the Kern County desert will be between 107 to 112
degrees.

The HREF indicates that the strong 500mb high pressure that has
been parked over the Great Basin is beginning to weaken and slowly
drift southeastward into northern Arizona. Today will feature one
last good push of subtropical moisture into the region. Also
there is additional remnant moisture from a dying multicell
convective system (MCS) currently over San Bernadino County that
is being pulled around the high pressure into the area. The best
chances for thunderstorms today will be over the Southern Sierra
from Fresno County south into Tulare County. This is where the
best instability and low level moisture exists. Thunderstorms in
these areas will be capable of heavy rain, hail, and strong
outflow winds in excess of 40 mph. There is also a slight risk of
dry thunderstorms over the far eastern portions of the Kern County
desert, but these will mostly produce strong outflow gusts up to
40 mph.

Heading into the weekend, the aforementioned high pressure over
Arizona will continue to slightly weaken. Additionally, there is
a deep trough off the Alaskan coast that will dig southward into
the PacNW. The synoptic cooling from these two features will help
"cool down" our afternoon high temperatures. However we'll still
be near the century mark for most locations, with the exception
of western Merced which will have more of an influence of cooler
marine air. The steering flow that has been bringing all this
subtropical moisture will stay to the east and south, and the
trough moving into the PacNW will also bring drier air into
central California. Looking at the long range into next week,
temperatures will begin to once again increase as the high
pressure over the desert southwest begins to strengthen.

&&

.AVIATION...
Isolated thunderstorms are expected in the Southern Sierra Nevada,
Kern County mountains, and Kern County desert until 03z Thursday.
Otherwise, VFR conditions will prevail over much of the central
California interior during the next 24 hours.

&&

.AIR QUALITY ISSUES...
On Wednesday August 19 2020... Unhealthy for sensitive groups in
Fresno... Kern... Kings... Madera... Merced and Tulare Counties
and Sequoia National Park and Forest.
Further information is available at Valleyair.org

&&

.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
an/or to provide feedback.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 9 PM PDT Thursday for CAZ179>191-
198-199.

&&

public...CMC
aviation....BS

weather.gov/hanford