Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 162220

Area Forecast Discussion
National Weather Service Sacramento CA
320 PM PDT Sun Oct 16 2016

Periods of rain...heavy at times, gusty winds, and high mountain
snow into Monday. Drier weather expected the rest of the week with
warming temperatures.


Wide area of light to moderate precipitation has continued over
southern portions of the CWA today with an embedded line of
moderate to heavy precipitation. This line has maintained its
identity throughout the day and has produced upwards of 3/4 of an
inch per hour. This has resulted in ponding of water on roadways
and sharp rises on small creeks thereby warranting issuance of an
urban and small stream advisory. The line is moving around 15 kts
to the east and approaching several burn scars but weakening
significantly as it does.

Meanwhile upstream front is pushing onshore along NW California
and will spread another round of widespread precip over the
northern half of the CWA this evening. Satellite showing some
clearing over the Northern and Central Sacramento Valley ahead of
front and latest HRRR showing an area of higher CAPE in these
areas to support isolated thunderstorms. Shear profiles continue
to support possible rotating storms.

KRDD-KSAC surface pressure gradient is up to 6 MB and wind
advisory criteria is occurring in the Northern Sacramento.
Strongest winds expected in this area for the Central Valley with
most other areas not likely to reach advisory criteria.

Snow levels presently around 7000 feet in the Shasta mountains to
well above 8000 feet over the Sierra Nevada. Snow expected to
remain above pass levels this evening but gradually lower
overnight to near 6000 feet in the north to 6500-7000 feet over
trans-Sierra passes. Light snow accumulations are possible at
Donner Pass on I80 and Echo Summit on Highway 50 tonight into
Monday. Lassen Park and higher elevations passes such as Carson
Pass, Ebbetts Pass and Sonora Pass could see more significant
amounts of snow impacting travel tonight. Winter Weather Advisory
for early season snow has been issued to address this.

GEFS/GFS showing integrated water vapor transport decreasing over
Interior NorCal Monday with models indicating main threat of
light showers confined to the foothills and mountains and possibly
Northern Sacramento Valley. Heights increase offshore Tuesday and
build inland through midweek resulting in drier weather with
warming temperatures.



A flat ridge will be in place over the west coast bringing dry
weather and slightly above normal temperatures on Thursday.
Systems passing to our north will keep the ridge relatively flat
and unchanged through the early part of the weekend. Both the GFS
and ECMWF show a weak trough approaching Northern California on
Sunday with the majority of the energy passing to our north. The
GFS brings in some high clouds to our area while the ECMWF has a
few sprinkles across the mountains. For now, we have kept the
forecast dry through the extended. Wilson


Another frontal band of rain will work its way south and east
this evening bringing MVFR and IFR conditions. Expect it to move
through KRDD around 02Z and KSCK around 06Z. Behind the front,
southerly winds will weaken. Somewhat concerned with the
development of low clouds and reduced visibility behind this front
tonight but not yet confident enough to put it in the TAF. In
general, improving conditions expected for the Southern Sacramento
and Northern San Joaquin Valley on Monday with showers confined
to the mountains and Northern Sacramento Valley. Wilson

Wind Advisory until 8 PM PDT this evening for Burney Basin /
Eastern Shasta County-Central Sacramento Valley-Northeast
Foothills/Sacramento Valley-Northern Sacramento Valley-Southern
Sacramento Valley-Western Plumas County/Lassen Park.

Areal Flood advisory until 5 PM PDT for eastern portions of the
Southern Sacramento Valley, Motherlode, and West Slopes of the
Northern Sierra Nevada.

Winter Weather Advisory until 11 AM PDT Monday for West Slope
Northern Sierra Nevada.


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