Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
FXUS66 KHNX 261040
Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
340 AM PDT MON SEP 26 2016
.SYNOPSIS...A warming trend will continue over the area today. A
surge of tropical moisture will bring a slight chance of mountain
thunderstorms on Wednesday and Thursday. Cooling will begin by mid
week and continue into next weekend.
.DISCUSSION...Clear skies prevailing across our area overnight as
Central CA remains under an offshore flow as a result of upper
high pressure over Norcal and the PAC NW and an upper low over
Baja. An unseasonably warm airmass prevails over our area and the
warming trend is expected to continue today as afternoon highs in
the San Joaquin Valley approach the century mark.
Meanwhile the upper low to our south is progged to move northward
on Tuesday and Wednesday. This will result in height falls across
our area and a slight cooling trend each day as a result of
synoptic cooling although temperatures will remain well above
seasonal normals. By Wednesday, the low is expected to push into
Socal and there is a possibility that some moisture from Tropical
Storm Roslyn currently centered near 17N/120W and drifting slowly
northward will get pulled up and wrap around into Kern and Tulare
Counties. In addition the low might provide for enough instability
over the mountains for a slight chance of thunderstorms over the
southern Sierra Nevada and Tehachapi mountains on Wednesday
afternoon and evening. This low is progged to be pushed east of
our area by Thursday as an upper trough deepens along the PAC NW
coast. RH progs are showing enough lingering mid/upper moisture
near the Southern Sierra Crest for isolated convection on
The medium range models are in fairly good agreement with
deepening the trough on Friday then pushing it inland over the
weekend. A fairly strong cold front is progged to push across
Central CA on Friday Night which will bring a period of increased
winds to the Kern County Mountains and Deserts and possibly the
west side of the San Joaquin Valley. It will also bring much
cooler temperatures to our area with highs next weekend progged
to be 5-8 Deg F below normal. RH progs are indicating the deeper
moisture with this trough remaining well to the north of our area
so precipitation is not anticipated. Ensemble means are
indicating the trough will shift east early next week with another
warming trend following for our area.
.AVIATION...VFR conditions will prevail over the Central CA
interior during the next 24 hours.
.AIR QUALITY ISSUES...On Monday September 26 2016... Unhealthy
for sensitive groups in Fresno... Kern... Kings... Madera...
Merced and Tulare Counties. Further information is available at
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.