Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
310 PM PST Monday Nov 30 2015
Update...updated air quality issues.
Synopsis...a low pressure system will pass over northern
California by this evening...however...precipitation is expected
to remain mainly north of Merced County. Otherwise...high pressure
with slightly warmer temperatures will prevail through Wednesday.
The next Pacific weather system is expected to move into
California on Thursday and bring a chance for precipitation
Discussion...an upper low pressure center approaching the Pacific northwest
is pushing a middle level deformation band into central California this
afternoon. While any precipitation with this feature is expected
to remain to the north of our area...it will provide for increased
middle level clouds this evening and inhibit radiational cooling
tonight enough for lows on Tuesday morning to be a few degrees
above today/S values. Therefore...after two straight mornings of
widespread freezing temperatures in the San Joaquin Valley...only
patchy frost is expected tonight as lows at most locations will
remain above the freezing mark...and we are therefore not planning
on issuing a freeze warning for the San Joaquin Valley for
18z WRF like previous WRF runs is indicating upper riding pushes
into central California on Tuesday and amplifies over the region on
Tuesday night and Wednesday while a surface high strengthens over
the Great Basin resulting in a dry and warming offshore flow with
mostly clear skies across our area. The warming aloft is expected
to result in a stronger near surface inversion over the San
Joaquin Valley on Wednesday and provide for more favorable
condition for fog late Tuesday night and Wednesday morning.
The next significant storm is prognosticated to move into norcal on
Thursday. Offshore winds developing ahead of this storm are
expected to provide for downslope conditions across the Tehachapi
Mountains and the south end of the San Joaquin Valley late
Wednesday night and Thursday...bringing increased winds and warmer
than normal temperatures to these areas. The storm itself is
expected to spread increased moisture into our area by Thursday
afternoon and bring a period of rain and higher elevation snow
Thursday night which will then taper off to showers by Friday
morning as the storm moves east of our area. Rfc quantitative precipitation forecast forecasts are
indicating a quarter to half an inch of liquid precipitation for
the southern Sierra Nevada north of Kings Canyon from Thursday
afternoon through Friday morning. Snow levels will be around 8000
feet on Thursday afternoon lowering to near 5000 feet by Friday
morning in the colder Post-frontal airmass. The San Joaquin Valley
is expected to pick up one to two tens of an inch of rainfall in
the east central portion while the west side and south end will
receive up to a tenth of an inch of rainfall.
Following the departure of the upper trough on Friday...the GFS
and ensemble means indicate another dry upper ridge is prognosticated to
build into central California on Friday night and Saturday and keep our
area dry through the weekend as the ridge keeps the storm track to
the north of our area. The operational European model (ecmwf) is further south with
the storm track and brushes our area with some precipitation early
next week. This solution does not have ensemble support that the
GFS has so it is being disregarded for the time being. Following
the idea of the ensemble means...storms moving through the Pacific northwest
on Sunday and Monday will bring some middle/high clouds to our area
and also provide for enough mixing to inhibit widespread fog in
the San Joaquin Valley. Temperatures will be above seasonal
normals early next week as a warm airmass prevails.
Aviation...areas of MVFR in mist/haze with local IFR/LIFR in fog
possible in the San Joaquin Valley between 09z and 18z Tuesday.
Otherwise...VFR conditions will prevail across the central California
interior during the next 24 hours.
Air quality issues...on Tuesday December 1 2015...
fireplace/wood stove burning status is: no burning unless
registered in Fresno... Kern... Kings... Madera and Tulare
counties. Further information is available at valleyair.Org
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is medium.
This information is provided as part of a trial project conducted
by the National Weather Service San Joaquin Valley - Hanford.
Certainty levels include low...medium...and high. Please visit
www.Weather.Gov/hnx/certainty.Php /all lower case/ for additional
information and/or to provide feedback.
site date hi_max:year lo_max:year hi_min:year lo_min:year
Kfat 11-30 77:1924 44:1972 57:2012 29:1906
kfat 12-01 76:1926 40:1905 56:2012 29:1906
kfat 12-02 74:1907 39:1972 60:2012 27:1906
Kbfl 11-30 83:1924 46:1965 54:2012 28:1907
kbfl 12-01 79:1903 44:1972 57:1909 27:2004
kbfl 12-02 87:1915 42:1972 58:2012 28:2004