Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
FXUS66 KHNX 030217
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
617 PM PST Fri Dec 2 2016
A cold front that moved through the region is bringing in colder
air with a possibility of freezing conditions in the San Joaquin
Valley tonight. Dry conditions this weekend. A weak trough will
move through the region on Tuesday. Gradually warming and dry
conditions are expected by the end of next week.
.DISCUSSION...High winds remain over the Sierra High Country with
Mammoth Mountain still gusting to over 70 mph. Winds for the most
part have failed to translate down the west slope canyons and are
no longer expected to do so this evening. &&
.PREV DISCUSSION... /issued 554 PM PST Fri Dec 2 2016/
Active weather day as Central California experiences fog, strong
winds and possible freezing temperatures. The day started with
areas of dense fog across the San Joaquin Valley while a jet max
above 30,000 feet approached the district from the Pacific
Northwest. Along with the strong winds, satellite imagery along
with upper air analysis showed very cold air filtering through
California and now pushing south of Southern California.
The fog did manage to mostly burn off by noon with patches of low
clouds lingering over the eastern side of the valley. Even as
winds picked up over many locations across Central California, the
orientation of the strong winds prevented the eastern side of the
San Joaquin Valley from mixing out under lighter winds. Tonight
will be fight between lingering moisture for fog and clear skies
for freezing conditions. The orientation of the jet max seems to
favor a more northerly meridional direction. While the Mono wind
event is still in effect under a High Wind Warning for the Sierra
Nevada, the direction is not truly perpendicular to the mountain
range. Therefore, today`s winds are not as strong due to the upper
and lower levels not being in-phase to produce the strongest
winds. Yet, the jet orientation will continue to introduce cold
air from the north for a much colder night.
Surface observations from Northern California were already showing
dew points in the mid 20s this afternoon. While Central
California is still showing dew points in the mid 30s, the
Sacramento area is now trending lowers and moving dew points below
30 deg-F. Models show the jet max moving into Southern California
later tonight into Saturday morning which will terminate good
surface mixing. As the atmosphere becomes more stable and dry,
will expect temperatures to reach the freezing mark before sunrise
on Saturday. Therefore, will upgrade the Freeze Watch to a Freeze
Warning and the Central and Southern San Joaquin Valley has a good
chance of observing a very cold overnight period.
Model then show another storm clipping the Sierra Nevada near
Yosemite on Monday/Tuesday ahead of another ridge pattern and
northerly winds early next week. Most of the district will remain
dry during the early week event. By the end of next week, the
ridge pattern flattens and a zonal flow pattern moves onto the
west coast. Currently, models confine the precipitation to the
Pacific Northwest and extreme Northern California. Will keep the
district dry for most of next week. Freezing temperature over the
San Joaquin Valley by the middle of next week is trending warmer
and will therefore wait until the weekend (and a closer look)
before messaging that event.
Areas of MVFR visibilities due to haze and mist across the San
Joaquin Valley through 17z. Strong wind exist aloft due to a robust
jet max moving through the region today. These winds have the
potential to erode the BR mention from the terminals early as winds
mix down. However, confidence in this remains low for gusty winds in
the San Joaquin Valley, though these will winds will exist across
the High Sierra. Otherwise, VFR conditions can be expected across
the central California interior during the next 24 hours.
.AIR QUALITY ISSUES...
On Saturday December 3 2016... Firepalce/Wood Stove Burning Status
is: No Burning Unless Registered in Fresno... Kern and Tulare
Further information is available at Valleyair.org
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.
Wind Advisory until 10 PM PST this evening CAZ095-098-099.
Freeze Warning from midnight tonight to 9 AM PST Saturday