High Wind in California, April 6 to 8, 2017

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
206 PM PDT Thu Apr 6 2017

.SYNOPSIS...Rain and high elevation snow will make its way into
the area tonight. The bulk of the rain/snow will fall tomorrow
into Saturday morning. There is a threat of thunderstorms,
especially on Saturday afternoon.

&&

.DISCUSSION...Water vapor imagery shows a good fetch of moisture
streaming into Central California today. The parent low continues
to sit well off the Oregon/Northern California.

That low will slowly ride the Pacific Northwest's coastline,
which will keep the associated cold frontal boundary out of the
forecast area. However, a secondary feature moves through the flow
on Friday which will kick a cold front through the area on
Saturday.

Before that happens however, attention will be on the
aforementioned moisture fetch and its precipitation. Deep moisture
will continue to slide into the area this evening, which will
allow the shower activity to increase. Tonight, the focus of
precipitation will likely be in the Yosemite area, though after
midnight things will spread southward.

Snow levels will start out around 8kft though expect with
evaporative cooling processes as precipitation starts those should
drop a thousand feet or so. That will not last long as warm air
slides into the area during the day Friday raising snow levels
back up again. Could see snow levels as high as 8500 ft in the
Central Sierra and almost 10kft in the Southern Sierra.

Nevertheless, there is a window where a couple feet of snow could
fall, so have upgraded the watch to a warning above 7kft from
Tulare County to Yosemite. Biggest concern in the warning area
will be reduced visibilities from blowing snow and falling trees
from increased snow load and wind.

Then as mentioned a cold front will move through which will lower
snow levels to 5-7kft, though the bulk of the moisture will be on
its way out. Snow can't be ruled out as mid level cooling on
Saturday will increase the possibility of thunderstorms across the
area.

Best area for thunderstorm development of Saturday looks to be on
the eastside of the valley, where a 100-300 J/kg of CAPE is
progged to exist. Convection should be fairly shallow and with a
fairly warm temperature profile hail growth should be limited.

All is all, the good news is this precipitation event will be
one and done show. And with most hydrologic basins and reservoirs
down from the levels seen in previous months the threat of
widespread flooding is lowered as well. Still, localized flooding
will likely be an issue across the area as will be quick rises in
smaller streams and ponds, especially near thunderstorms and areas
prone to flooding.

Otherwise, the extended forecast looks fairly quiet until the day
7-8 timeframe when potential for rain/snow returns. Stay tuned.

&&

.AVIATION...Areas of MVFR and local IFR spreading south over the Sierra in
clouds and precip, becoming widespread MVFR and areas of mountain
obscuring IFR after 06Z Friday. Local MVFR in the San Joaquin Valley
in precip spreading north to south after 06Z Fri.

&&

.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 from 5 AM Friday to 11 AM PDT Saturday
ABOVE 7000 FEET FOR THE CAZ096-097.

&&

public...Meadows
avn/fw...DCH

weather.gov/hanford