Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
310 am PDT Tuesday Jul 22 2014
mostly clear skies over the region as weak high pressure prevails.
A warming trend will begin on Thursday and continue into the
weekend. Thunderstorms will once again be possible along the Sierra
crest Sunday into early next week.
Discussion...an upper level short wave continued to move
northeast toward the sf Bay overnight...bringing middle and high
level clouds to mainly the southern half of California. This has
moderated temperatures slightly...with many locations running
between 2 and 4 degrees warmer compared to this time yesterday due
to the insulation of the clouds. As of 2 am...temperatures in the
valley were generally in the low to middle 70s...but are forecast to
fall another 5 or so degrees before sunrise.
Upper level high pressure remains firmly planted
over The Four Corners region while an upper low continues to dig
south toward the Pacific northwest from the British Columbia coastline. This
upper low allowed the marine layer to deepen to just over 2000
feet and brought moderate onshore flow and a slightly cooler
airmass to the region. Temperatures this afternoon will be similar
to those observed yesterday afternoon...with valley readings
generally in the low to middle 90s. The coolest valley temperatures
will be observed along the western half of Merced and Madera
counties...where the marine air influence will be the strongest.
These temperatures are a few degrees below normal for the middle
to end of July.
The upper low will continue to dig south and move east onto the
Washington/or coastline on Wednesday...resulting in another slightly below
normal day for temperatures. Wednesday temperatures will be nearly
identical to those forecast for this afternoon.
The upper low will quickly move east Thursday into
Friday...allowing for the upper ridge to shift slightly west and
bring a warming trend to the area. Significant warming is expected
both on Thursday and Friday...with daytime high temperatures
warming between 2 and 4 degrees each day. By Friday...valley
temperatures will warm to the triple digits once again.
Upper level flow is forecast to back from a southwest direction on
Friday to a southerly direction on Saturday and finally to a
southeasterly direction on Sunday. This southeasterly flow will
allow monsoonal moisture to surge north into the area and bring a
slight chance for thunderstorms along the Sierra crest Sunday into
the first part of next week. Exact timing of these thunderstorms
is still a bit uncertain...allowing for only medium confidence
in the extended portion of the forecast.
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 medium.
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 07-22 112:2006 83:1896 84:2006 56:1903
kfat 07-23 113:2006 84:1918 90:2006 55:1897
kfat 07-24 113:2006 87:1999 85:2006 55:1903
Kbfl 07-22 113:1908 82:1984 88:1910 50:1903
kbfl 07-23 114:1931 86:1903 83:2006 54:1914
kbfl 07-24 115:1908 83:1999 83:2006 52:1914