Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
FXUS66 KHNX 091248
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
448 AM PST Fri Dec 9 2016
Some light showers are possible today, but most areas should
remain dry. Rain and high elevation snow will affect areas mainly
from Fresno County north on Saturday and precipitation could be
heavy at times, especially around Yosemite NP. Dry conditions are
likely Sunday and Monday, then precipitation chances return Tuesday.
An unseasonably mild air mass is in place now courtesy of a moist
zonal flow pattern. Satellite imagery shows lots of clouds continue
to spread inland but radar is relatively quiet. Latest scans show
an area of light showers crossing over Point Conception, with a
smaller batch of weaker echoes moving into the Tehachapi mountains.
Unsettled conditions will continue today but do not expect much in
the way of activity or accumulations.
The atmospheric river is being funneled towards the coast between
a Gulf of Alaska low and an upper ridge to its south. Blended TPW
shows a large area around 1" just off the central California coast.
About 400 miles offshore is the leading edge of a 1.5 - 1.7" core.
A s/wv trough rounding the Gulf low is progged to push towards
northern California tonight and steer this higher moisture towards
the coast. Expect precipitation to spread down after midnight with
increasing coverage and intensity after 12Z and continuing through
the day Saturday. The bulk of activity will occur from Fresno Co.
northward and especially in and around Yosemite NP. Precipitation
should taper off Saturday night with some light upslope showers
possible into Sunday morning. Latest QPF from 12Z Sat - 12Z Sun
has around 1-2" rainfall in the Sierra from Yosemite NP to Kings
Canyon NP, around 0.5" in Sequoia NP and only 0.1" - 0.25" for the
mountains in Kern County. The San Joaquin Valley could see around
0.5" in Merced County, 0.1" - 0.3" from Fresno Co. to the Kern Co
line and maybe a few hundredths in Kern Co. Snow levels will remain
above 8,000 feet for the bulk of the event with 1 to 2 feet of new
Sunday and Monday are looking dry now as the moisture axis shifts
south and diminishes. Precip chances return on Tuesday as another
surge from the atmospheric river is possible. The GFS is the most
bullish with this as it has a s/wv trough off the Pacific NW dig
down and spread precip as far south as Kern Co. The ECM shows the
offshore ridge amplifying building inland and thus just briefly
brushes areas from Fresno Co northward.
The models are still suggesting the potential for a wet and colder
end to next week, but there is quite a bit of uncertainty between
models as well as run-to-run within models. The ECMWF brings this
system in next Thursday with additional waves maintaining precip
chances into the weekend. The GFS has now slowed it considerably
until Friday night, while the GEM holds it off until next Saturday.
Temperatures will be a few to several degrees above normal through
at least the middle of next week. A tightening onshore surface
pressure gradient will develop Saturday for breezy conditions in
many areas and windy conditions possible through and below the
Kern County mountain passes.
For the next 24 hours, across the San Joaquin Valley and southern
Sierra foothills, areas of MVFR and local IFR possible in low clouds
and rain. In the southern Sierra Nevada and Tehachapi Mountains,
widespread MVFR with local IFR in precipitation and mountain
obscurations. VFR conditions will prevail across the Kern County
.AIR QUALITY ISSUES...
On Friday December 9 2016...Fireplace/Wood Stove Burning Status
is: No Burning Unless Registered in Kern...Kings and Tulare
Counties. Further information is available at Valleyair.org
The level of certainty for days 1 and 2 is medium-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.