Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
FXUS66 KHNX 281045
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
345 AM PDT SAT MAY 28 2016
.SYNOPSIS...A weak upper level system will move into the region
today which will increase chances of afternoon and evening showers
and isolated thunderstorms for the mountains through Sunday. High
pressure will move in beginning Memorial Day bringing a return to
drier and much warmer conditions through next week.
.DISCUSSION...A weak upper low is currently dropping through
central CA in a northwest flow aloft. IR imagery is indicating
some high clouds with this feature, but radar composites are not
indicating any precipitation at this time. Meanwhile mid level
warming along with continued thickness rises will result in
continued warming across our cwfa with afternoon highs expected
to be 2-4 DEG F above Friday`s readings at most locations and
exceed seasonal normals at most locations for the first time in
over a week. The surface warming combined with the cooling aloft
provided by the weak upper low will result in increased
instability across our area this afternoon provided for increased
chances of showers this afternoon and evening over the Southern
Sierra Nevada and Tehachapi Mountains. The 06Z WRF is indicating
CAPES above 600 J/KG over these area this afternoon along with
increased instability and upper level moisture so isolated
thunderstorms cannot be ruled out either.
The low is progged to move slowly east across Socal on Sunday
which will bring a continued chance of mountain showers and
isolated mountain thunderstorms as a result of instability and
increased CAPE during the afternoon and evening hours. The low
will move into the Desert Southwest during the Memorial Day
holiday while a large area of high pressure moves inland. The
large high will bring a continued warming trend to our area with
afternoon highs expected to be well into the 90s across most of
the San Joaquin Valley and Kern County Deserts. With less
instability and a much drier airmass prevailing on Memorial Day,
afternoon convection will be confined to the Southern Sierra
The medium range models and their ensemble means are in fairly
good agreement with shifting the large area of high pressure
slowly inland Tuesday through Friday which will result in a
period of mostly clear skies and much warmer than normal
temepratures across our area. In fact, most guidance is indicating
much of the San Joaquin Valley is expected to have maximum
temperatures in the triple digits by Tuesday and a potential for
even warmer daytime temperatures toward the end of the week.
.AVIATION...Areas of MVFR and local IFR in showers and isolated
thunderstorms can be expected over the mountains between 20z today
and 04z Sunday. Otherwise, VFR conditions will prevail over the
central California interior during the next 24 hours.
.AIR QUALITY ISSUES...None.
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is high.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.