Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
323 am PST Monday Dec 29 2014
Synopsis...continued mostly clear skies today with weak high
pressure over the region. Colder by midweek with a slight chance
of showers Tuesday into Wednesday...and snow over the Kern County
mountains and desert.
Discussion...a northerly flow aloft is prevailing over our
region as a result of interaction between an upper ridge off the
western Continental U.S. Coast and a cold upper trough over the inter-
mountain west. With a dry airmass currently situated over our
area...one more mostly sunny and dry day is expected across our
area today before an upper low currently situated over the Pacific northwest
plunges southward...pulling an Arctic airmass into our area by
However...relative humidity forecasts are not indicating much moisture with this
system and the 06z WRF and high resolution models are indicting
the low will drop southward further east than earlier anticiapted.
This may result in less precipitation coverage and amounts for our
area than earlier anticipated although there is still the
potential for travel to be adversely impacted on Tuesday night
and Wednesday morning over the Kern County mountains and deserts
where a Winter Storm Watch remains in effect as the snow level is
expected to plunge to 1500 feet by Wednesday morning and liquid
snow ratios are expected to be high due the the Arctic origin of
Another impact from this system is the potential for strong
northeast winds over the higher elevations of the southern Sierra
Nevada on Tuesday night and Wednesday as that area will be the
northwest of the low center which will make it favorable for
strong downslope during that period. Rfc quantitative precipitation forecast amounts are fairly
light with this system...with up to a quarter inch of liquid
equivalent over the Kern County mountains as well as over the high
elevations of the southern Sierra Nevada. Up to a tenth of an inch
is possible along the floor of the Kern County deserts...but with
snow ratios expected to be high...up to 2 inches of snow will be
possible in the deserts Tuesday night through Wednesday morning
while up to 6 inches will be possible in the Tehachapi Mountains.
Have noticed that the 00z and 06z model runs have been trending a
bit drier however...so this will need to be re-assessed by the day
shift. The models are in good agreement that this system is
prognosticated to track east across the Desert Southwest on Wednesday
night and Thursday resulting in clearing skies and the end of any
precipitation chances for our area.
The medium range models and their ensemble members are showing
good consensus in slowly building the offshore ridge inland Friday
through the weekend which will result in dry conditions and a
noticable warming trend for the higher elevations. This will also
result in the return of night and morning fog for the San Joaquin
Aviation...in the San Joaquin Valley...local MVFR in mist near
mce through 18z today. Otherwise...VFR conditions can be expected
throughout the central California interior during the next 24 hours.
Air quality issues...on Monday December 29 2014...
fireplace/wood stove burning status is: no burning unless
registered in Fresno... Kern... Kings... Madera... Merced 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 high.
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 12-29 69:1949 36:1908 54:1977 24:1990
kfat 12-30 67:1904 36:1902 54:2001 24:1969
kfat 12-31 69:1997 36:1929 53:1913 23:1975
Kbfl 12-29 73:1956 40:1929 57:1977 22:1929
kbfl 12-30 74:1904 44:1986 53:1981 15:1905
kbfl 12-31 73:1913 39:1919 53:1981 19:1929
Winter Storm Watch from Tuesday afternoon through Wednesday