Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 211245
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
445 AM PST Sat Jan 21 2017

.SYNOPSIS...Scattered showers will linger in the lower elevations
through today with snow showers continuing over the mountains.
The next storm will bring another round of rain and mountain snow
to the region tonight through Monday. A drying trend will begin
on Tuesday with a continuation of dry weather for the remainder
of next week.

&&

.DISCUSSION...The low pressure system that was responsible for
producing the heavy rain, mountain snowfall, flooding and strong
winds to our area on Friday has moved east of our area. Meanwhile,
unsettled conditions continue across our area with troughy
conditions prevailing and radar composites are indicating showers,
mainly over the mountains; continuing across our area overnight.

The short range models are indicating a continuation of unsettled
conditions across our area today with showers at times. The main
weather concern now turns to yet another incoming storm which has
the potential to be the strongest storm to impact our area so far
this season. WV imagery is indicating a moist baroclinic band
stretching from 130W out to 170W which is taking aim at central
CA. GOES high density winds are indicating that this feature is
being pulled up by a strong upper low centered near 47N/143W and
being pushed eastward straight toward central CA. This deep
moisture fetch is progged to reach our area by this evening and
continue through at least midday Monday. During this time frame
periods of moderate to heavy precipitation are expected across our
area along with increased winds in favored areas. As the result of
the anticipated heavy snowfall and strong winds in the mountains,
a Winter Storm Warning has been issued for the Southern Sierra
Nevada where 2 to 4 feet of additional snowfall are expected over
the higher elevations. Snow levels will be between 4500 and 5000
feet on satruday evening when this system arrives and rise to 7500
to 8000 feet by Sunday afternoon in a modified tropcial airmass.
As the large offshore upper low approaches the Norcal coast Sunday
night, cooler air will push into CA and snow levels will lower to
3500 to 4000 feet by Monday. Over the Kern County Mountains a
strong pressure gradient will result in very strong winds on
Sunday with gusts up to 90 mph possible in the Grapevine area. the
precipitation over the passes will turn to snow on Sunday night
as the cooler air pushes in. A Winter Storm Warning has also been
issued for the Kern COunty Mountains with emphasis on the strong
winds. However, the snowfall on Sunday Night and Monday might also
have an adverse impact on travel over the the major passes.

Meanwhile, moderate to heavy rainfall over the lower elevations
on top of an already saturated ground will bring a renewed threat
of flooding on Sunday, Sunday Night and Monday across the San
Joaquin Valley and southern Sierra foothills. With a colder
unstable airmass prevailing across our area on Monday,
thunderstorms will be possible over the San Joaquin Valley as well
as across the mountains and deserts of Kern County.

The trough will move east of our area on Tuesday with a cyclonic
flow keeping cool and unsettled conditions across our area.
Isolated showers will continue our area on Tuesday before a drier
airmass builds into the area by midweek. The medium range models
are in fairly good agreement with an amplifying upper ridge off
the CA coast during the second half of next week which will keep
our area under a dry northerly flow. Mainly clear skies will
prevail over the higher elevations while night and morning fog
will return to the San Joaquin Valley as inversion conditions
become more prevalent.

&&

.AVIATION...
SAN JOAQUIN VALLEY...MVFR conditions in with isolated showers
through 06z Sunday then rain over region.
SIERRA NEVADA AND KERN COUNTY MOUNTAINS...Widespread mountain
obscurations and scattered showers through 18z. Strong gusty over
mountain ridges.
KERN COUNTY DESERT... Strong gusty winds below the mountain passes
until 18z Saturday...otherwise VFR conditions can be expected
elsewhere across the central California interior during 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...
Winter Storm Warning until 10 AM PST this morning CAZ096-097.

Winter Storm Warning from 10 PM this evening to 10 AM PST Monday
CAZ096-097.

Winter Storm Warning from 10 PM this evening to 10 AM PST Monday
CAZ095.

&&

$$

public...DS
avn/fw...Dudley
synopsis...DS

weather.gov/hanford



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