Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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870
FXUS66 KHNX 182234
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
334 PM PDT Wed Oct 18 2017

.SYNOPSIS...
Temperatures will trend much cooler through Friday as a storm
system moves over northern California. This system will bring a
chance for light precipitation Thursday night and Friday along
with an increase in winds. Dry weather will return later this
weekend with a warming trend into early next week.

&&

.DISCUSSION...
Weak shortwave impulse continues to move east out of the area
leaving behind just some lingering mid and high cloudiness.
Temperatures are similar to this time yesterday, on track to top
out a few degrees above normal.

A more significant developing trough approaching the northwest US
coast will bring a notable change to our weather beginning
tomorrow. Models handle this synoptic feature similarly as it is
progged to swing inland beginning Thursday. Increased onshore flow
across our area along with lowering heights and thicknesses will
provide several degrees of cooling for Thursday. Westerly winds
will increase as surface pressure gradients tighten in response to
the approaching trough.

Models keep the main associated energy and moisture to the north
of our area so precipitation will not be a big factor with the
passing system for central CA. A band of frontal precip is
progged to reach the Yosemite vicinity late Thursday night and
spread southward into Kern County by Friday morning. QPF will be
mostly confined to the Sierra zones and favored upslope areas in
Kern County. Rainfall amounts in these areas are progged at
generally 1/10 of an inch or less. Snow levels initially l0000 ft
or more will fall as low as 8 to 9000 ft in the Sierra by Friday
morning. Can`t rule out some sprinkles or light showers in the SJV
with the passing front late Thursday night and Friday morning. By
Friday afternoon, should see just some lingering upslope showers
in the Kern County mountains. Maximum snow accumulations are
forecast to be 1-2 inches at the highest Sierra elevations.

BY Friday, cooler air behind the front will keep temperatures
around 10 degrees below climo. After Friday, models remain in good
agreement. Notable high pressure is progged to build over the west
coast through the weekend into the middle of next week. This will
bring dry and warming conditions, with temperatures returning to
around normal by Monday and a few degrees above by midweek.


&&

.AVIATION...
Areas of MVFR visibilities due to smoke and haze can be expected in
the San Joaquin Valley, southern Sierra foothills and higher
elevations of the southern Sierra Nevada for at least the next 24
hours, with VFR conditions prevailing elsewhere across the Central
California Interior.

&&

.AIR QUALITY ISSUES...should
On Wednesday October 18 2017... Unhealthy for sensitive groups in
Kern County.
Further information is available at Valleyair.org

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is high.
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.

&&

.HNX Watches/Warnings/Advisories...
NONE.
&&

$$

public...JEB
avn/fw...Andersen
synopsis...JEB

weather.gov/hanford



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