Winter Storm Warning 10, NWS Hanford, CA

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
352 AM PST Sun Feb 19 2017

.SYNOPSIS...Unsettled weather will return to the area on Sunday
afternoon and continue through at least the middle of next week.

&&

.DISCUSSION...Mainly zonal flow is present over central
California and is forecast to dominate the area through at least
Monday morning. Expect mainly dry conditions across the area today
with temperatures near to slightly below normal.

Unsettled weather returns to the area as early as this afternoon
as a broad upper trough slowly moves east toward the California
coastline.

The high res ARW and NMM as well as the HRRR are all in agreement
that precipitation will spread east into western Merced and Fresno
counties by 00z Monday and quickly spread east through the entire
area by 06z to 09z Monday. Precipitation will generally shift to
the Sierra Nevada by 15z...with little to no precipitation over
the San Joaquin Valley...other than a few scattered
showers...through at least Wednesday. Steady moderate to
occasionally heavy precipitation is forecast for much of the
Sierra Nevada from this afternoon and evening through at least
Tuesday.

The upper trough will be tapping into abundant moisture that
extends well west of the Hawaiian Islands. Precipitable water
values with this plume of moisture will be well in excess of 1
inch. This will bring significant precipitation to mainly the
Sierra Nevada and surrounding foothills during the first part of
the week.

Again the focus of this storm will be over the mountains and
foothills. The heaviest precipitation will occur early Monday
morning through early Tuesday morning with the Sierra
Nevada...below 7000 feet...and the foothills picking up between 1
and 3 inches of rain during this time frame. The valley will see
between a tenth of an inch in the south valley to near an inch in
the north valley.

This abundant precipitation...especially in such a short time
frame...will create flooding problems across the region once
again. Expect rapid rises on area rivers and creeks as well as mud
and rock slides. Generally the area that will be of greatest
concern will be from Fresno county northward...where the bulk of
precipitation will fall. Those communities who have experience
flooding problems in the past few months are urged to monitor the
forecast closely.

Snow levels will hover between 7000 and 8000 feet between Sunday
afternoon and Tuesday morning...with between 20 and 40 inches of
new snow from Kings Canyon National Park northward. South of Kings
Canyon can expect between 10 and 20 inches of snow above the snow
line.

Unsettled weather will continue over mainly the higher elevations
Tuesday into early Wednesday as the upper trough shifts southeast
toward the central California coastline. The valley will see
another shot of precip on Wednesday as the upper trough axis moves
through the area.

There looks to be a break in the weather Thursday into Friday
before another round of precipitation impacts the region next
weekend.

&&

.AVIATION...Areas of MVFR ceilings can be expected in the Sierra
foothills until 21z today. MVFR ceilings with local IFR in drizzle
and fog will occur along the north facing slopes of the Kern County
mountains through 19z today. IFR conditions will develop southward
over the Sierra after midnight tonight as precipitation overspreads
the region. VFR conditions will prevail 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
and/or to provide feedback.

&&

.HNX Watches/Warnings/Advisories...
Flood Watch from this afternoon through Tuesday morning
CAZ089-090-093-094-096-097.

Winter Storm Watch from this afternoon through Tuesday morning
ABOVE 7000 FEET FOR THE CAZ096-097.

&&

public...Riley
avn/fw...Durfee
synopsis...Riley

weather.gov/hanford