Weather Service Report


695 
FXUS66 KHNX 261040
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
340 AM PDT THU MAY 26 2016

.SYNOPSIS...
Scattered showers and thunderstorms will continue this afternoon and
evening over the Sierra Nevada and Kern County mountains. A gradual
warming trend is forecast into early next week.

&&

.DISCUSSION...
The upper level disturbance affecting the weather over Central Cal
is finally moving through Arizona this morning. While a few clouds
were still lingering over the San Joaquin Valley and adjacent
higher elevations, the atmosphere has become stable enough to
terminate showers. At the surface, the pressure gradient from SFO
to LAS continues to float around 10mb as afternoon winds across
the Tehachapi's and Mojave desert gusts up to 15 to 20 mph. While
temperature trends across the region has shown little change, will
expect today's afternoon max values about 2 to 4 deg-f above those
observed on Wednesday afternoon.

By this afternoon, the upper level disturbance will push pass the
four corners region as it moves toward the Great Plains. At that
point, the west coast will be under the influence of a
northwesterly flow pattern. While meso-scale models indicate good
instability over the Sierra Nevada, the northerly to northwesterly
flow aloft will push any blow-off away from the SJValley. Models
are progging another low dropping into the Pacific Northwest later
this week. While not dropping the low closer to the district,
models do show a strong jet over western Oregon on Friday with
difluent flow over Central California. Therefore, enough upper
level support may exist for better mountain convection on Friday.
Models show even better instability on Friday for more widespread
mountain convection. 

An area of weakness will then shift over the west coast during the
weekend to reduce the instability over the Sierra Nevada.
Therefore, will trend drier and warmer as a ridge of high pressure
moves toward the west coast next week. Will not completely
terminate mountain convection during the development of the ridge
pattern as residue moisture and weak instability maintain mountain
showers through at least next Tuesday. As the ridge become the
dominate feature, temperature will see a warming trend that may
peak toward next Tuesday/Wednesday when the ridge axis is
overhead. The end of the forecast period will see a transition
back to cooler conditions as yet another trof digs toward the west
coast. At this point, model uncertainty remains high, but are
trending toward a developing trof pattern. At the moment, will
hold-off on the introduction of precip until maybe closer to the
Thursday time frame.

&&

.AVIATION...
Widespread MVFR and areas of mountain obscuring IFR across the
Sierra Nevada and Tehachapi Mountains in showers and low clouds
after 20z Thursday. Otherwise, VFR conditions will prevail in the
central CA interior for the next 24 hours.

&&

.AIR QUALITY ISSUES...
None.

&&

.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.php for additional information
an/or to provide feedback.

&&

.HNX Watches/Warnings/Advisories...
None. 

&&

$$

public...Molina
avn/fw...JDB
synopsis...WP

weather.gov/hanford

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Western Regional Climate Center, wrcc@dri.edu