Scientific Forecaster Discussion
fxus66 khnx 272053
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
153 PM PDT Sat may 27 2017
high pressure will build over the region with warmer temperatures
and a light offshore flow through Tuesday. A cold front will
cross the region on Wednesday with a brief cool down, then warming
temperatures once again by Friday. Isolated showers and
thunderstorms are possible each day in the Sierra Nevada through
Wednesday and down into the Kern County mountains on Wednesday.
stratus clouds that formed over the central San Joaquin Valley
this morning, dissipated by late morning as a ridge of high
pressure began to build inland. The building ridge along with a
light offshore flow is bringing warming temperatures across
central California with temperatures running 5 to 15 degrees
warmer than 24 hours ago. Afternoon cumulus are beginning to
develop early this afternoon and expect buildups across the
Sierra crest with an isolated shower or thunderstorm possible
later this afternoon and evening.
As the ridge continues to shift slowly east the next few days,
expect temperatures to continue to warm a few degrees each day,
with Monday likely being the warmest day. The chance of showers
and thunderstorms over the higher elevations of the Sierra Nevada
will continue each day through Tuesday.
Guidance continues to be in decent agreement that a trough of low
pressure and associated weak cold front will move through the
region Tuesday night and Wednesday. We will start to see some
cooling across Merced County in advance of the front on Tuesday as
the ocean cooled air will flow through the Pacheco Pass.
Temperatures will drop back to near normal across the entire
central California interior by Wednesday. With the trough and
front moving through, there will be a more moisture and
instability for shower and thunderstorm development over the
Sierra and Kern County mountains on Wednesday. We are not
expecting any precipitation in the San Joaquin Valley or Kern
desert areas with the front at this time.
Beyond Wednesday, the extended models still have some disagreement
with the intensity and track of a storm system forecast to move
into the Pacific northwest late next week. The 12z GFS was still a bit
farther south with the system than the European model (ecmwf) or the ensembles, but
it was trending farther north than previous runs. Confidence in
the forecast for Friday into next weekend is still rather low.
Temperatures 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 over central California,
which means warmer temperatures and drier conditions based on
consistent trends with the ensembles.
areas of MVFR and local IFR possible over the Sierra Nevada crest
due to mountain obscurations from isolated thunderstorms thru 04z
sun and again after 20z Mon. Otherwise, VFR conditions are expected
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.