Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
302 am PDT Tuesday Oct 21 2014
Synopsis...a cooling trend will occur today with breezy winds
likely this morning across the west side of the San Joaquin Valley
and the Kern County mountains and deserts. High pressure will
return for the remainder of the week with dry conditions
continuing and temperatures warming to above normal by Thursday.
Another system will bring increased clouds along with a cooling
trend by Saturday.
Discussion...a fairly strong cold front pushed through central
California last evening bringing breezy to locally wind conditions to our
County warning forecast area with a few locations in the Kern County mountains and deserts
reporting gusts just above 40 miles per hour. The breezy conditions are
expected to continue through late this morning then taper off the
afternoon as p-grads relax.
Meanwhile...fog imagery is indicating some upslope low clouds
banked up along the south end of the San Joaquin Valley and the
valley facing slopes of the Tehachapi Mountains. Some patches of
fog have been reported near Tehachapi along Highway 58 this
morning as well. The low clouds and patchy fog as well as some
patchy drizzle will continue through late this morning when
p-grads decrease. Temperatures across our area will lower to near
seasonal normals today in the cooler Post-frontal airmass.
The 06z WRF is in good agreement with prior runs indicating an
upper ridge will build into California on Wednesday then shift inland into
the Great Basin by Thursday while a moisture fetch takes aim at
the Pacific northwest and extreme norcal. The only impact the moisture fetch
will have on our area for the remainder of the work week will be
some high clouds at times. Temperatures will trend upward each day
through Friday in response to rises in heights and diurnal
The medium range models and their ensemble members remain in very
poor agreement in their handling of a moist upper trough which is
prognosticated to cross the Pacific northwest and norcal Friday night through
Saturday night. The 00z GFS indicates the southern extent of
precipitation with this system will brush our northern most area
in Merced and Mariposa counties late Friday night and early
Saturday while the 00z European model (ecmwf) is indicating the potential for a
significant precipitation event across much of our County warning forecast area on
satruday night as it is much stronger with this system.
However...with poor run to run consistency and poor ensemble
agreement confidence in any one model run for next weekend is very
low. We have increased precipitation chances for our northern
most areas for Friday night and across much of our area from
Fresno County northward for Saturday and have increased sky cover
Saturday. Cooler temperatures are also expected over the weekend
along with increased winds over the Sierra crest along as over the
normally wind prone areas along the west side of the San Joaquin
Valley and in Kern County.
Finally...a dry upper ridge is prognosticated to build back into California
early next week which will result in a warming and drying trend
for our area by Monday.
Aviation...wind gusts to 35 knots are likely around the Kern
County mountain passes until 18z Tuesday. Areas of MVFR ceilings
along the west slopes of the Sierra and the north facing slopes of
the Tehachapi Mountains until 21z Tuesday. VFR conditions will
prevail elsewhere across the central California interior during
the next 24 hours.
Air quality issues...none.
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 10-21 93:2003 58:1941 60:1992 34:1949
kfat 10-22 92:1948 63:2012 64:1982 35:1961
kfat 10-23 90:1965 57:1956 64:1982 35:1975
Kbfl 10-21 94:2003 62:2004 65:1976 32:1906
kbfl 10-22 95:1901 63:1985 65:1982 37:1920
kbfl 10-23 97:1929 64:1975 65:1982 34:1906