Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA

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FXUS66 KHNX 281126

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
420 AM PDT Sun May 28 2017

.SYNOPSIS...A ridge of high pressure will bring above normal
temperatures and dry weather to much of the central California
interior through Tuesday. Isolated afternoon thunderstorms will
occur each day near the Sierra crest. A storm system will bring
much cooler weather to the district Wednesday with a chance of
showers and thunderstorms over the mountains.


.DISCUSSION...Temperatures are running several degrees higher
across much of the CWA this morning compared to 24 hours ago.
That`s a trend that will continue through the holiday weekend
as an upper level ridge of high pressure builds over the Golden
State. Max temperatures will be in the lower 90s in the San
Joaquin Valley, lower foothills and the Kern county desert this
afternoon. Memorial Day will be at least a few degrees warmer.
An upper level trough off the Pacific Northwest coast will
nudge the high pressure ridge eastward into the Four Corners
region Monday night then reestablish an onshore flow across
central California Tuesday with the start of another cooling
trend. The cooldown will begin with a deepening of the marine
layer along the coast Monday night. Marine air will begin to
infiltrate the northern San Joaquin Valley Tuesday where
cooling will be most noticeable. More significant cooling will
occur Tuesday night and Wednesday as the upper level trough
settles southward over the Golden State.

Up until Wednesday, afternoon and early evening thunderstorms
over the Sierra will be few and far between and generally
confined to the highest elevations. Showers and thunderstorms
will become more numerous over the Sierra Wednesday. The
thunderstorm threat could extend southward into the Kern county
mountains by Wednesday afternoon as the upper level trough
digs southward over our CWA.  Otherwise, high temperatures on
Wednesday will be a good 7 to 15 degrees cooler than Tuesday in
most locations.

The upper level trough will exit into the Great Basin Wednesday
night and a dry northwesterly flow aloft will reside over central
California in its wake Thursday. Other than residual morning
cloudiness along the west facing slopes of the Sierra and the
north facing slopes of the Tehachapi mountains, Thursday should
turn out mostly sunny with temperatures recovering to seasonable
levels. Short wave ridging aloft will bring dry weather and
further warming to the central California interior Friday.

The models develop a weak upper level trough along the California
coast next weekend which in turn will probably mark the beginning
of yet another cooling trend, at least along the coast. In spite
of this trough, the models forecast further warming across the
central California interior next weekend. The GFS is more bullish
with the warmup than any of the other models. Given this uncertainty,
we are forecasting little change in temperatures on days 6 and 7.
Max temperatures next weekend will depend on the strength of the
onshore flow and just how deep the marine layer gets along the coast.
Either way, the weather pattern looks dry across the CWA next weekend.


Areas of MVFR and Local IFR possible over the Sierra Nevada crest
due to mountain obscurations from isolated thunderstorms after 20Z
today thorugh 04z Mon. Otherwise, VFR conditions are expected across
the central CA interior during the next 24 hours.





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 for additional information
an/or to provide feedback.


.HNX Watches/Warnings/Advisories...


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