Flood and Heavy Snow in California, December 7 to 8, 2019

Area Forecast Discussion
National Weather Service Hanford CA
229 PM PST Fri Dec 6 2019

.SYNOPSIS...
A weather system will affect the district from late tonight
through the end of the weekend with rain and thunderstorms in the
valley, along with heavy rain and snow into the Central Sierra.
foothills and mountains. Ridge will build into the area for
Monday and Tuesday, with morning fog possible. Quick, dry short
wave moves through Central California on Wednesday, before ridge
builds across the area into the end of next week.

&&

.DISCUSSION...
For the rest of the afternoon, strong southeasterly winds will
continue along the Grapevine and West Side Hills where local gusts
up to 55 mph are possible in these locations. Wind Advisories
will remain in effect until tonight for the Grapevine and through
Saturday morning for the West Side hills.

Going forward into Saturday, deep upper level trough will
continue to make its way toward the CA/OR coast. Light
precipitation associated with warm-frontal overrunning will begin
overnight and increase in coverage into Saturday. Precipitation
through the morning in the valley will be mostly north of Fresno
County with only light amounts expected. However, heavy
orographic snow will begin into the Central Sierra overnight and
will increase in intensity through all day Saturday. As such, A
Winter Storm Warning will go into effect at 10 PM PST tonight, and
will remain in place through Sunday evening. Snow levels will
begin around 7500 feet, before falling to 6000 feet by Saturday
evening after the passage of a cold front.

Showers and afternoon thunderstorms will become likely Saturday along
and ahead of the approaching front. Thunderstorms will be able to
produce locally heavy rainfall, lightning, although hail and
funnel clouds can not be ruled out. Rainfall will move southward
through the day, with precipitation reaching the southern end of
the valley by late in the evening. Precipitation totals will
remain light, although higher amounts can occur within
thunderstorms. Of course with the favored orographical lift, the
heaviest precipitation will occur in the foothills and mountains.
Little to no precipitation is expected in the Kern County desert.

On Sunday, main upper level low will move southward through
Central California, with scattered showers and thunderstorms
once again possible in the valley Sunday afternoon. Snowfall will
continue all day in the Sierra, with snow levels remaining around
6000 feet. Trough exits the area by Sunday evening, with
precipitation ended across the area. Storm total precipitation
over the weekend will range from 1/10 to 1/4 inches in Kern County
and into the western portion of the valley. Between 1/2 to 2/3
inches is possible in the northern and eastern portions of the
valley. Locations in the Central Sierra foothills will receive
between 1 to 2 inches of rain below 6000 feet, with locally
heavier amounts. Snowfall will range from 3 to 6 inches with
locally up to a foot between 6000 and 7000 feet, and between 1 to
3 feet above 7000 feet. Less than 1/10 of an inch of precipitation
is expected in Kern County mountains and desert.

Models show precipitation ending late Sunday into early Monday,
with a ridge building into the area on Monday into Tuesday. With
ample surface moisture and high pressure aloft, morning fog will
become an issue on Monday and Tuesday morning. A weak short wave
trough moves through Central California on Wednesday, with little
to no precipitation expected, but winds might be an issue on
Wednesday as the trough exits the area. From Wednesday onward into
the end of the forecast period on Friday, flat ridge builds
across the region along with dry conditions. However, morning fog
will once again become a issue.

&&

.AVIATION...
Surface winds gusting to 45 knots along West (Coastal) Hills and
around the Grapevine area is likely through 15Z Saturday. MVFR
conditions likely in low clouds and precipitation in the valley
beginning at 12Z Saturday continuing all day along with scattered
thunderstorms are possible in the valley between 18Z and 00Z
Saturday. Mountain obscurations and IFR conditions in clouds and
precipitation after 06Z Saturday.

&&

.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.html for additional information
an/or to provide feedback.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from 10 PM this evening to 7 PM PST Sunday
for CAZ192>194.

Wind Advisory until 4 PM PST this afternoon for CAZ197.

Wind Advisory until 7 AM PST Saturday for CAZ179.

&&

public...CMC
aviation....BSO

weather.gov/hanford