Scientific Forecaster Discussion
fxus66 khnx 282316
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
416 PM PDT Fri Apr 28 2017
gusty conditions in the San Joaquin Valley will diminish
overnight; while gusty downsloping winds are expected to develop
over parts of the Sierra and foothills this evening through early
Saturday morning. Lighter winds, warming temperatures and dry
weather will then prevail this weekend into early next week as
high pressure strengthens over the region.
upper low pressure over The Rockies and high pressure over the
eastern Pacific has central California under a fast north-northwest flow
aloft. Daytime heating has allowed some of these winds to mix down
to the surface leading to gusty conditions across much of the San
Joaquin Valley. Winds gusts of 35-45 mph are expected to continue
into the early evening, but after sunset will diminish through
the night. The Wind Advisory for the sjv remains in effect through
11 PM tonight. While winds diminish in the valley, they are likely
to increase across parts of the Sierra this evening. Surface high
pressure building over northern Nevada will turn the pressure
gradient offshore with a NE to SW flow over the southern Sierra.
At the same time, winds around 50 kts are progged at 700 mb. The
hi-res models are showing the potential for strong gusty winds,
mainly over the High Sierra, but locally into the foothills through
the river canyons. A Wind Advisory has been issued for the Sierra
and adjacent foothills from Yosemite to Kings Canyon np from 8 PM
this evening to 8 am Saturday morning. The combinations of high
tree mortality and moist soil conditions will bring an increased
potential for downed trees. The pressure gradient weakens Saturday
morning and the flow aloft diminishes, ending the threat of strong
Otherwise, sunny skies will prevail this weekend with temperatures
warming as the upper ridge noses inland. Highs are expected to be
a little above climo Saturday then a few degrees warmer on Sunday.
A weak upper trough dropping southeast over the Great Basin will
halt the warming on Monday. It should also bring some breezy
conditions to the sj valley again on Monday, but not as strong as
the last couple of days have been. Models agree with the ridge
over the eastern Pacific building inland early next week. This
will bring further warming with highs forecast to be around 10
degrees above early may normals next Wed-thurs. Parts of the sj
valley, mainly in the south end, are expected to reach into the
lower 90s. The medium range models agree with some cooling to end
the week with an approaching Pacific trough. The GFS is the most
aggressive with the cooling on Friday as a sharp trough reaches
the coast. The European model (ecmwf) has a much slower and weaker trough for more
subtle cooling on Friday.
surface winds gusts above 35kt are expected across the San Joaquin
Valley thru 06z Saturday producing local reduction in visibility due
to blowing dust. Otherwise, VFR conditions will prevail across the
central California interior during the next 24 hours.
Air quality issues...
The level of certainty for days 1 and 2 is medium.
The level of certainty for days 3 through 7 is high.
Certainty levels include low...medium...and high. Please visit
www.Weather.Gov/hnx/certainty.Php for additional information
an/or to provide feedback.
Wind Advisory until 11 PM PDT this evening caz089>092.
Wind Advisory from 8 PM this evening to 8 am PDT Saturday