Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
339 PM PST Tuesday Jan 27 2015
Update...air quality issues updated.
Synopsis...another low pressure system will bring a renewed
chance of showers to mainly the mountains and desert Wednesday
night into Friday. Otherwise expect mainly dry conditions with
near to slightly above average temperatures through the next
Discussion...shower activity quickly diminishing as an upper low
moves NE of the Sierra. The South Valley has cleared out with
showers limited mainly to the mountains. Expect all shower
activity to end during the early evening. Weather radar
precipitation estimates shows widespread light precipitation
falling over much of district with the heavier amounts of 0.6-1.0
inch over the Tehachapi Mountains and Indian Wells Valley. Concern
for the potential for fog in the sjv tonight. Dew points running
relatively high with the recent rainfall. Winds should remain
light as short wave ridging builds behind the exiting trough. A
mitigating factor will be amount of remnant cloud cover. However
models forecast decreasing middle level moisture behind the trough.
High level cloud cover will be on the increase Wednesday as an
upper trough off Baja California moves towards the socal coast. Satellite precipitable water
estimates indicate lots of tropical moisture ahead of this system.
However models forecast the deep moisture to push through the Sonoran
Desert and remain east of the Colorado River. Models split the
trough as it moves onshore with the stronger dynamics moving
trough north Baja California. Thus model forecast light amounts of precipitation
mainly over the mountains and desert. Precipitation could begin
Wednesday night and diminish Thursday night. The ensemble mean
trends remain inconsistent with the track of this low...giving
forecasters very little confidence in measurable rain...especially
for the desert.
Once the upper low exits east...high pressure will build over the
region Saturday into Sunday...with the operational and ensemble
means all in agreement. The beginning of next week looks a bit
less certain...as nceps global ensemble showing very low
predictability for the upper level pattern for the beginning of
next week. Regardless...both the GFS and European model (ecmwf) are indicating dry
Patchy fog will once again be possible through many valley
locations starting as Thursday. Patchy fog will be possible each
night and early morning from Thursday into early next week.
MVFR ceilings can be expected along the west slopes of the Sierra
and the north facing slopes of the Tehachapi Mountains until 18z
Wednesday with improvement to VFR thereafter. Areas of IFR
ceilings and visibilities are possible in the San Joaquin Valley
between 06z and 18z Wednesday with local LIFR/vlifr in fog. VFR
conditions will prevail elsewhere throughout the central
California during the next 24 hours.
Air quality issues...
on Wednesday January 28 2015... 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 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 01-27 70:1934 39:1963 52:2012 25:1949
kfat 01-28 78:1986 41:1963 50:2003 23:1975
kfat 01-29 73:1960 43:2002 55:1911 24:1902
Kbfl 01-27 75:1928 37:1963 51:2012 24:1904
kbfl 01-28 77:1988 47:1957 52:1981 27:1957
kbfl 01-29 74:1986 42:2002 54:1986 27:1903