Winter Storm Warning 1, NWS Hanford, CA

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
305 AM PST Sun Jan 7 2018

.SYNOPSIS...High pressure will remain over the area today
before a strong storm system moves into Central California
Monday night through early Wednesday.

&&

.DISCUSSION...Satellite imagery continues to show a big fetch of
mid and high level moisture streaming northeast into California
from around 15N/130W. An associated upper low continues to spin
near 22N/135W and this feature will become a part of the complex
weather scenario that is expected over the next 48 to 72 hours.
Meanwhile, way out around 45N/155W a disturbance is noted moving
rapidly to the east. This is the other weather system that is
projected to combine with moisture from the southern low to bring
a significant storm to the forecast area later Monday through
early Wednesday. I'll keep the drama to a minimum and update the
models and how they project the development and movement of this
storm.

Confidence has increased that in this very dry and "ridged" wet
season, this system will bring the first significant rain and snow
to most areas. A very moist airmass with available moisture
values at 4 standard deviations above normal (this is rather
significant) will advect into the forecast area today and Monday
ahead of the developing low pressure area which models continue to
deepen and push towards the Central California coast on Monday
afternoon and evening. As the surface low intensifies offshore,
pressure gradients (the difference between high and low pressure)
will increase and strong southerly winds will develop. A high
wind watch remains in place for the Kern County Mountains,
especially the Grapevine area and the Western Kern, Kings, Fresno
and Merced Counties as the difference in pressure from southern to
northern California will be the greatest. Winds will likely peak
Monday evening and overnight as a strong south to north jet stream
aligns with the pressure gradient.

Precipitation will begin on Monday in the increasing moist southwest
flow aloft into the area however the heaviest rain and high
elevation snow will begin Tuesday morning as a strong cold front
sweeps across the region. Cold air aloft then follows as the upper
level low is progged to move across Central California during the
afternoon. This will lower snow levels, turn the precipitation to
a more showery nature and increase instability enough for the
threat of thunderstorms. Latest qpf indicates some heavier snow
will fall above 7000 feet in the Sierra and with the arrival of
colder air, several inches of snow is likely over the Kern County
mountains above 5500 feet by Tuesday afternoon.

By Tuesday night the low is projected to move quickly east of the
area and this will bring lower elevation showers to an end with
some lingering snow in the Sierra through the night. On Wednesday
the low is progged to move into Arizona with all precipitation
ended in Central California in the morning. Models then build a
ridge over the region beginning Thursday for a return to dry
weather.

&&

.AVIATION...
Areas of IFR conditions in mist in the San Joaquin Valley, along
with local LIFR in fog through 18Z Sunday. Otherwise VFR conditions
will prevail elsewhere over the next 24 hours.

&&

.AIR QUALITY ISSUES...
On Sunday January 7 2018... Fireplace/Wood Stove Burning Status
is: No Burning Unless Registered in Kern... Kings and Tulare
Counties.
Further information is available at Valleyair.org

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is medium.
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 Watch from Monday evening through Tuesday evening
CAZ096-097.

High Wind Watch from Monday afternoon through Tuesday morning
CAZ091-092-095-099.

High Wind Watch from Monday morning through late Monday night
CAZ089-090.

&&

public...Dudley
avn/fw...MV
synopsis...Dudley

weather.gov/hanford