Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
235 am PST Friday Dec 26 2014
a cool northerly flow will prevail over the region as high pressure
remains off the West Coast...low temperatures will reach the
coldest so far this season tonight. As the high moves inland by
early next week...temperatures are expected to moderate slightly.
a cold...dry airmass is in place over interior central California
this morning. At 09z /0100 PST/ this morning...dewpoints in the
central and southern San Joaquin Valley were in the middle 20s to middle
30s...and only in the teens to middle 20s in the Kern County desert and
the Indian Wells Valley. Could see some valley locations drop to
around freezing by daybreak...or even a degree or two below 32
briefly...but temperatures are expected to be even colder tonight
under clear skies and light winds. A freeze watch is in effect for
the central and southern San Joaquin Valley for late tonight into
Saturday morning...and a hard freeze watch is in effect for the Kern
County desert. The wording for the hard freeze watch includes
references to the Indian Wells Valley as some locations there will
be in the middle 20s...although not a large enough area for the
formatter to generate a hard freeze watch for zone 98.
Temperatures for Christmas day were near normal...for the first
time since middle December. Through Christmas day...this continues to
be the warmest December on record...due in large part to well above
normal overnight lows. The coming cold spell will lower the average
temperature for December some...but the month could still rank in
the 10 warmest decembers on record.
An upper-level short-wave is forecast to drop through he Pacific
northwest over the weekend and into the Great Basin by Sunday night.
This short-wave will keep the east-Pacific upper-level ridge off the
coast and maintain a northerly flow aloft over California.
Beginning Monday night...the GFS and European model (ecmwf) begin to diverge with the
GFS being the more progressive model. The GFS sets up a northeast
500-mb flow over the southern Sierra Nevada Tuesday...but the
ensemble relative measure of probability /rmop/ does not have high
confidence in this solution. The European model (ecmwf) has a more easterly flow
aloft as it has an upper-level low over northern California.
By New Year/S day...the European model (ecmwf) slowly drops the low southward over
California to over Kings County by 18z /1000 PST. Thursday. At the
same time...the GFS has a low over northern Arizona.
The GFS would support a Mono-type wind event over the central Sierra
Nevada Tuesday into Tuesday night...although the surface-pressure
gradients are not as favorably oriented as for a true Mono wind
event. This could change...however...in later model runs.
Could see some upslope showers over the southern Sierra Nevada and
Tehachapi Mountains Tuesday if the drying Mono winds fail to
develop. Have kept probability of precipitation in the slight chance category due to model
in the San Joaquin Valley...local MVFR visibilities in mist through 18z
today. Otherwise...VFR conditions can be expected throughout the
central California interior during the next 24 hours.
Air quality issues...
The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is low.
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 12-26 70:1892 38:1908 55:1983 21:1987
kfat 12-27 72:1991 37:1908 55:1977 23:1962
kfat 12-28 66:1945 35:1908 54:1977 24:1962
Kbfl 12-26 71:1999 35:1918 56:1977 20:1905
kbfl 12-27 72:1991 39:1933 56:1977 23:1930
kbfl 12-28 73:1977 40:1908 58:1977 24:1930
freeze watch from late tonight through Saturday morning for the
central and southern San Joaquin Valley /caz089>092/.
Hard freeze watch from late tonight through Saturday morning for
the southeastern Kern County desert and parts of the Indian Wells