FXUS66 KHNX 271050
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
350 AM PDT Sat May 27 2017
Surface high pressure will build over the Great Basin and
increase offshore flow and increase temperatures through Tuesday
across the region. A cold front will cross the region on Wednesday
with a cool down through the end of the week. Isolated showers
and thunderstorms are possible each day in the Sierra Nevada and
down into Kern county mountains on Wednesday.
Offshore flow is trying to set up across the region attm. Some
valley clouds are starting to erode as upper ridge axis builds in
overhead. Temperatures will bump up today to around normal as
skies will be clearer than yesterday. Upper ridge axis will move
east through the weekend and increase temps across the CA Interior
through Tuesday. The warmest day looks to be Memorial Day with
temps 8-12 degrees above normal.
Afternoon cumulus buildups across the Sierra Crest are possible
starting today with an isolated shower or thunderstorm this
afternoon and continuing through Tuesday.
Guidance is in decent agreement that a trough will move through
the region on Wednesday. We will start to see some cooling across
Merced county in advance of the front as the ocean cooled air
will flow through the Pacheco Pass and cool off Merced and
Mariposa counties in the valley on Tuesday. Temps will drop back
to near normal across the entire CENCAL Interior by Wednesday.
This cool down will be brief as weak ridging will once again bring
temperatures back to above normal Thursday through Saturday.
Unsettled weather is expected in the Sierra and Kern County
mountains on Wednesday as the front moves through. We are not
expecting any precip in the SJV or Kern Desert areas with the
front attm on Wednesday.
NAEFS, GEFS and ECM are not in very good agreement with the
intensity and track of a storm system forecast to move into the
PAC NW late next week, which is giving less confidence for the
extended forecast beyond next Friday. Temps might be overdone if
the track is farther south with an increase of showers in the
Sierra. For now we are staying with a farther north track and more
ridging...which means warmer temps and drier conditions based on
consistent trends with the GEFS.
Local MVFR ceilings can be expected in the Sierra foothills and
along the north facing slopes of the Tehachapi mountains until 19z
today. Otherwise, VFR conditions will prevail across the central
California interior during the next 24 hours.
.AIR QUALITY ISSUES...
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.php for additional information
an/or to provide feedback.
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