Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
345 am PDT Monday Aug 31 2015
Synopsis... dry weather can be expected over the central
California interior for the next several days. Temperatures
will average slightly below normal for much of this week as
an onshore flow prevails. Gusty winds can be expected in the
Kern County mountains and desert each afternoon and evening.
Discussion...skies are mainly clear over the central California interior
this morning and temperatures are certainly cooler than 24 hours
ago in most locales with 24-hour trends currently down 3 to 13
degrees. Although surface pressure gradients between sfo and las
are down a few millibars compared to Sunday morning...a healthy
onshore flow persists over the County Warning Area. Low stratus that was present
along the central California coast Sunday morning is mostly nonexistent
as of this writing on current satellite imagery. Nonetheless...
marine air will remain pooled in the sj valley today and with a
persistent onshore flow...high temperatures in the sj valley and lower
foothills will fall shy of seasonal normals again today. Above
the marine layer...there will be a few degrees of synoptic warming
today with maximum temperatures ending up slightly higher over the mountains
and desert compared to Sunday.
A minor warmup is likely over the entire County Warning Area Tuesday as an upper
level ridge centered over the Desert Southwest builds westward.
The warmup will be rather short-lived and will be reversed by
the passage of a dry cold front across central California Wednesday
evening and night. Prior to its arrival...Wednesday could be
equally as warm as Tuesday over the southern half of our County Warning Area
while northernmost areas become more influenced by an increase in
onshore flow and the spillage of marine air through the SAC Delta.
A deepening upper level trough over the Pacific northwest during the middle
of this week will bring a return of a robust onshore flow across
the County Warning Area from late Wednesday through Thursday evening. During this
time...west winds will become gusty again through and below the
mountain passes along the west side of the sj valley and in Kern
County. Maximum temperatures Thursday will probably remain below 90 degrees
throughout much of the sj valley and lower foothills thanks to a
return infiltration of marine air which will likely remain pooled
in the sj valley through Friday.
The deterministic model runs diverge in the 5 to 7 day period.
The ecm deepens the upper level trough over California while the GFS shows
flat ridging aloft. The question as to whether Labor Day weekend
will be cooler or warmer can best be answered by the ensembles
which shows no deepening trough but rather a zonal flow aloft
across central California. This agrees more closely to the GFS solution
so we opted for warming in the extended periods...particularly
Sunday and Labor Day. Either way it looks as though the weather
pattern will remain Bone dry through day 7.
areas of MVFR and local IFR visibilities can be expected in the
foothills and higher elevations of the southern Sierra Nevada due
to smoke. Local gusts around 35-40 kts are possible through and
below the mountain passes of Kern County through this evening.
Otherwise VFR conditions will prevail over 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 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 08-31 107:2007 69:1964 75:2007 50:1887
kfat 09-01 107:1888 73:1964 76:2007 51:1964
kfat 09-02 108:1955 76:2000 77:1998 48:1964
Kbfl 08-31 111:1967 79:1966 80:2007 45:1912
kbfl 09-01 107:1902 74:1964 79:2007 53:1901
kbfl 09-02 110:1955 74:1910 78:1998 50:1913