Area Forecast Discussion
Issued by NWS Sacramento, CA

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000
FXUS66 KSTO 141101
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
401 AM PDT Thu Sep 14 2017

.SYNOPSIS...
A few showers possible later today and tonight across the northern
mountains as a cold front slides south. Cooler temperatures today,
then readings return to around average for the weekend.

&&

.DISCUSSION...
Dry weather has returned to the region. Temperatures are cooler
ranging from the upper 30s in the mountain valleys to the 60s to
around 70 in the Central Valley. Stronger onshore flow is bringing
stratus inland into the southern Sacramento and northern San
Joaquin Valleys.

Northern stream trough deepens along the West Coast today and
pushes a cold front south later today and tonight. Showers and
thunderstorms may develop along the front across the northern
mountains and northern Sierra Nevada as it moves south. Cooling
will continue to spread inland today as synoptic cooling increases
and onshore flow continues.

Dry and milder weather returns for the weekend as the trough
weakens across NorCal.

&&

.EXTENDED DISCUSSION (Monday THROUGH Thursday)
Models a bit out of sync in the extended forecast. Both the GFS
and ECMWF show a trough pattern dominating the West Coast, but
these models disagree as to how far south the trough will dig and
how much precipitation is possible across NorCal. The ECWMF is
more aggressive in bringing the trough over our CWA with good
chances of precipitation for a couple days. The GFS limits
moisture over NorCal and quickly pushes the trough to our east.
Have kept the possibility of precip across the northern and Sierra
portions of our CWA through midweek next week, though not as
expansive coverage as the ECMWF suggests. Although precipitation
coverage has lower confidence, we are confident in a significant
cooling pattern. Daytime highs could range 10-20 degrees below
normal by Tuesday (coolest day) and the Sierra could flirt with
snow levels in the 7000-7500 ft range. JBB

&&

.AVIATION...
MVFR ceilings possible near KSMF, KSAC, KMHR early this morning,
otherwise,VFR conditions will prevail across the region today.
Winds should range from calm up to around 12 kt at TAF sites
today, except gusts to 30 kt near the Delta.

&&

.STO WATCHES/WARNINGS/ADVISORIES...None.

&&

$$



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