Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
FXUS66 KHNX 232341
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
341 PM PST Mon Jan 23 2017
.SYNOPSIS...A storm system off the Pacific Northwest coast will
bring wet weather to much of the central California interior
through this evening. Showers and higher elevation snow will
linger over the mountains through Tuesday as the storm exits into
the Great Basin. Although a few showers could return to the Sierra
Thursday, dry weather will be the rule from Wednesday through the
.DISCUSSION...The final storm system in a succession of storm
systems that have impacted the central California interior during
the past week is currently centered off the Pacific Northwest
coast. The entire CWA is in the left front quadrant of the upper
level jet this afternoon and underneath a very cold pocket of
air aloft (500 mb temperatures are near -32 C). Instability
showers and thunderstorms, some with small hail and briefly
heavy precipitation, have been tracking southeastward across the
district today. Precip has fallen as snow at elevations as low
as 2500 feet in the Sierra and about 4000 feet in Kern County
where wintry weather and slick travel conditions exist this
As the atmosphere stabilizes early this evening, shower activity
will diminish, particularly over the lowest elevations such as
the San Joaquin Valley. Mountain communities will probably
continue to get some showers into Tuesday, especially in the
upslope areas, as the storm system tracks southeastward into the
Great Basin. Although isolated showers could rejuvenate over
the higher terrain Tuesday afternoon, much of the central
California interior will finally get a break from wet weather.
However, the models forecast a good deal of low level moisture
to linger through Tuesday night, so low clouds could plague
much of the San Joaquin Valley and adjacent foothills for at
least the next 24 to 36 hours.
Otherwise, a northwesterly flow aloft will reside over central
California during the next couple of days. A weak upper level
disturbance embedded in the northwest flow could bring a renewed
chance of light showers to the Sierra mainly north of Kings
Canyon Thursday. Afterward, an upper level ridge of high pressure
over the eastern Pacific will gradually build over the Golden
State and will dominate the pattern in the 5 to 7 day period
with dry weather, light winds and mainly clear skies. During
this time, night and morning fog will become rather prolific in
the San Joaquin Valley. Temperatures will average pretty close
to normal during the next few days, perhaps becoming a bit cooler
over the Sierra Thursday where showers may return. Friday through
next Monday will trend warmer, although stubborn low clouds and
slow fog dissipation in some locations of the San Joaquin Valley
could reverse that trend.
On a final note, rainfall so far this month has averaged well
above normal. As of this writing, Fresno has surpassed January,
1995 as the 3rd wettest January on record and Bakersfield is in
the Top 10. There`s been a substantial increase in the snowpack
over the southern Sierra during the past couple of weeks which,
as of this morning, was averaging 238 percent of normal for the
Isolated thunderstorms can be expected until 04z Tuesday.
Otherwise, IFR conditions will prevail over the southern Sierra
and the Kern County mountains through 15z Tuesday with mountain
obscurations in heavier precipitation. MVFR conditions can be
expected in the Sierra foothills and along the north facing
slopes of the Tehachapi mountains through 18z Tuesday. V
VFR conditions will prevail elsewhere 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 high.
Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.php for additional information
an/or to provide feedback.
Flash Flood Watch until 8 PM PST this evening CAZ093>097.
Winter Storm Warning until 8 PM PST this evening CAZ093>099.