Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
356 PM PDT Thursday Oct 20 2016
above normal temperatures will prevail through the first half of the
weekend. A storm system will approach northern California this
weekend, bringing a cooling trend to central California Sunday into
Discussion...satellite imagery shows anticyclonic flow aloft over
the region with the center of the upper ridge west of northern Baja
California. Sunny skies prevail over central California with 24 hr trends showing
temperatures up several degrees from yesterday. Offshore surface
flow is producing some gusty east to southeast winds of 20-30 mph
through the Kern County mountain passes.
The ridge will bring further warming on Friday with highs climbing
into the mid-upper 80s across the San Joaquin Valley and Kern County
desert, nearly 10 degrees above normal in some locations. Offshore
flow will weaken with light terrain driven driven winds prevailing.
The ridge quickly shifts east through Saturday as heights begin to
lower ahead of an epac upper trough. This will bring slight cooling
to the district with an onshore flow developing.
The trough deepens off the California coast on Sunday as a cold upper low
drops south off the pacnw coast. The models are beginning to show
better agreement with the pattern evolution into next week, though
timing differences are evident. The 12z European model (ecmwf) still suggests some
sub-tropical moisture ahead of the trough will get pulled up far
enough west for some possible showers Sunday night into Monday.
GFS/Gem keep it over the lower Colorado River valley. There is
better agreement with the upper jet driving a rich moisture plume
towards northern California on Tuesday. The focus will be to our north but
close enough to warrant some slight to low chance pops from Fresno
County northward, with Yosemite np seeing the best chances. The
trough digs southwest off the coast Wednesday with another closed
low forming as upper ridging builds up over the western Continental U.S.. the
12z GFS wobbles the low towards the coast through the end of next
week with moist southwest flow aloft of 2"+ precipitable water. The European model (ecmwf) is about
12 hours slower but also very moist, while the Gem is even slower
and not so moist. So there is low confidence in this right now as
it is also a week away. But definitely something to watch for a
potentially wet end of next week.
Confidence is good that we will see temperatures cool off back to
near normal early next week. Not as confident as we move into the
middle to latter half of the week, with little change forecast.
Winds will increase on Sunday with breezy to gusty conditions, but
not expected to reach advisory levels.
VFR conditions will prevail at all terminals through the next 24
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 for additional information
an/or to provide feedback.