Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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975
FXUS66 KHNX 170115 AAA
AFDHNX

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
515 PM PST Sun Dec 16 2018

...Updated Air Quality Section...

.SYNOPSIS...A weather system will move into and across the
Central California Interior tonight and Monday bringing rain
and mountain snow to most areas. High pressure will then
build over the West Coast through much of the upcoming week
for dry and warmer weather.

&&

.DISCUSSION...Satellite imagery shows a classic cloud signature
over the area with thicker clouds over the northwest part of the
forecast area and nearly cloud skies over most of Kern County.
Regional radars show light precipitation moving into the Bay Area
east to Stockton and Modesto but thus far nothing any farther
south. As for movement of the incoming low pressure system, water
vapor imagery shows the main frontal band aligned nearly north to
south along the coast with clouds and precipitation moving
southwest to northeast along this boundary.

With the north to south orientation of the front, movement to the
east will be slow initially and the latest high resolution rapid
refresh model generates some rain in Western Merced County after 6
pm with the bulk of precipitation arriving after 8 pm and ending
around sunrise. Same model drives the front southeast through the
overnight hours with lingering showers noted through Monday
morning. Instability will increase over Merced, Madera and Fresno
Counties later tonight in the wake of the front as colder air
aloft arrives and given convective parameters including negative
lifted indices and in coordination with Storm Prediction Centers
general thunderstorm risk for the area, a few thunderstorms seem
and good bet over this area. Not much threat of thunder to the
south and east as the instability will lift northeast pretty
rapidly.

As for winter weather, snow accumulations of 9-12 inches are
generated by the latest qpf forecasts and this matches up really
well with the Winter Weather Advisory. Snow levels look to fall to
around 6000-6500 feet for the bulk of the precipitation evening
with some areas seeing some minor accumulation down to around 5500
feet in Yosemite Park in the colder, more unstable air.

All precipitation is expected to come to an end Monday night.
Models then are in good agreement in building a high pressure
ridge over the region Tuesday through Thursday for warming and
drying weather. Based on how much additional rain falls in the fog
prone San Joaquin Valley, low visibilities may become an issue as
early as Tuesday morning Wednesday and Thursday the days most
likely to have persistent dense fog. The ridge does weaken as a
decaying trough of low pressure moves across far Northern
California on Friday. This looks to be followed by a dry northwest
flow pattern in the big travel pre Christmas weekend next week.

Taking a quick look at any white Christmas possibilities, as of
today the long range has some promise in the mountains of Northern
California however for us down this far south...it looks dry for
now.

&&

.AVIATION...
MVFR in showers/mist for the San Joaquin Valley along with mountain
obscuring IFR conditions across the Sierra Nevada and Kern County
Mountains becoming a possibility after 03Z Monday. Over the
desert...VFR conditions will prevail over the next 24 hours.

&&

.AIR QUALITY ISSUES...
On Monday December 17 2018... Fireplace/Wood Stove Burning Status
is: No Burning Unless Registered in Fresno... Kern... Kings...
and Merced Counties.
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 medium.

Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
an/or to provide feedback.

&&

.HNX Watches/Warnings/Advisories...
Winter Weather Advisory from 4 PM this afternoon to 4 PM PST
Monday Caz093.

&&

$$

public...Dudley
avn/fw...Molina
synopsis...Dudley

weather.gov/hanford



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