Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
FXUS66 KHNX 242100
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
200 PM PDT TUE MAY 24 2016
.SYNOPSIS...Scattered showers and a slight chance of
thunderstorms will be possible over much of Central California
through Wednesday. A slight gradual warming trend is forecasted
during the latter part of week as weak high pressure moves in over
.DISCUSSION...An upper level low pressure system centered just to
the north of our area as depicted by GOES high density winds is
providing for another day of unseasonably cool temperatures and
unsettled weather across our area this afternoon. While
temperatures have been generally running a few degrees above yday,
orographic lift and instability have produced some showers over
the southern Sierra Nevada and over the western foothills of the
San Joaquin Valley. The low is progged to retrograde westward
slightly to off the CA coast later today then drop southeast just
off the CA coast tonight and early Wednesday before pushing east
into the desert southwest Wednesday afternoon and evening. As the
low slowly drifts off the coast, orographic lift will continue
for the remainder of the day resulting in continued showers across
our area with the exception of the Kern County Deserts. Isolated
thunderstorms cannot be ruled out for this afternoon and the
evening as instability is present with the WRF indicating LI`s
between -1 and -3 Deg C in the San Joaquin Valley and between -3
and -5 Deg C in the Southern Sierra Nevada.
The WRF is indicating sufficient instability and mid level
moisture over our area tonight and early Wednesday as the low
drops southward off the CA coast for a continued chance of showers
over the southern Sierra Nevada and Tehachapi mountain ranges with
the snow level expected to range between 8000 and 8500 feet.
As the low moves east into the desert southwest on Wednesday
afternoon, backwash moisture and lingering instability will
provide for continued chances of showers and isolated
thunderstorms in the southern Sierra Nevada and Tehachapi
mountains. Isolated convection will also be possible in the Kern
County Deserts on Wednesday as the WRF is indicating some
instability and high CAPES. By Wednesday night, the low will be
far enough east of our area so that the backwash showers should
taper off. A chance of showers still exists over the Southern
Sierra Nevada on Thursday while the remainder of our area clears
out under a dry northwest flow as our area will be in between an
upper trough over the Great Basin and an amplifying a dry upper
ridge off the western CONUS coast.
The medium range models are in fairly good agreement today in
handling the overall pattern later this week and are in good
agreement with the end of this morning`s WRF run with the dry
northwest flow over our area from Thursday onward into the early
portion of next week. Daytime temperatures will rise to near
seasonal normals by Friday then level off through the holiday
weekend. While RH progs are indicating the likelihood of skies
remain mostly clear across our area from Friday onward, there will
enough instability near the southern Sierra Nevada crest for a
slight chance of afternoon thunderstorms each day while the
remainder of our area stays dry from Friday onward.
.AVIATION...Areas of mvfr for ceilings in the San Joaquin Valley
and southern Sierra foothills in showers and isolated
thunderstorms through 06z Wednesday. Widespread MVFR and areas of
IFR in the southern Sierra Nevada and Tehachapi Mountains for
showers and thunderstorms with mountain obscurations in low
ceilings and precipitation. Otherwise, VFR conditions will prevail
in the central CA interior for 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 medium.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.