River Flood Warning 26, NWS Sacramento, CA

Area Forecast Discussion
National Weather Service Sacramento CA
450 AM PST Wed Feb 8 2017

.Synopsis...
Moderate to heavy precipitation with areas of breezy to gusty
winds will continue this week as a series of Pacific storms affect
the region. Flooding concerns will continue. Drier weather returns
for the weekend.

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.Discussion...
Very mild and juicy airmass (TPW in excess of an inch) continues
to stream up into NorCal ahead of the deep trough over the eastern
Pacific. Rain has slackened off for most of interior NorCal
overnight, but 12 hour precip amounts of an inch or two still
occurred over the foothills and Sierra Nevada to the east of
Stockton. Temperatures are very mild early this morning, ranging
from the 30s and 40s in the mountains to the 50s and lower 60s
elsewhere.

Precip will increase across the area today as strong warm-
advection moves overhead. Orographic enhancement will focus
heaviest precipitation over the mountains north of Redding and
across the west slopes of the northern Sierra and southern Cascade
Range where additional QPF of 2-4 inches can be expected over the
next 24 hours. Very high snow levels will limit snowfall
accumulation to just the highest peaks.

Surface pressure gradients will continue to tighten across the
region today with breezy conditions expected to return. Stronger
gusts of 40 mph or higher may develop as early as mid-afternoon
across the far northern portion of the Sacramento Valley and
surrounding terrain.

Gradients will continue to tighten overnight tonight into early
Thursday with the Sacramento to Medford gradient forecast to reach
about 17 mbs. Gusts of 50 mph or higher will be possible across
the northern half of the Sacramento Valley while winds will
increase elsewhere across the region.

Precip may decrease and shift northward a bit late tonight as the
offshore system approaches, then heavy precip returns Thursday
into Thursday evening as the front moves south through the area.
Another 1-2 inches of rain can be expected in the valley with 3-6
inches in the foothills and mountains likely resulting in more
flooding issues.

Snow levels are forecast to go below pass levels again Thursday
night and motorists should be prepared for winter travel over the
Sierra.

Showery post-frontal precip is expected Friday with the potential
for thunderstorms in the Central Valley if ingredients come
together, then drier weather expected to finally return Friday
night into the weekend.

&&

.EXTENDED DISCUSSION (Sunday THROUGH Wednesday)
A few snow showers may linger over the mountains into Saturday,
but by and large most of the region will be dry under building
high pressure. A brief period of breezy north winds will be
possible over the weekend, mainly along the western Sacramento
Valley and along favored Sierra canyons. High pressure should
continue to bring dry weather and perhaps some Valley fog through
the middle of next week. Longer-range models are currently
suggesting a return to wet weather toward the end of next week. Dang

&&

.AVIATION...
Light to moderate rain will continue across much of the region
the next 24 hours, with VFR/MVFR conditions expected across the
Valley, and IFR/LIFR over the mountains. South winds generally
below 10 kt will increase to 10 to 20 kt this afternoon, with
gusts up to 40 kt possible near KRDD-KRBL. Dang

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 2 PM this afternoon to 4 PM PST Thursday for
Burney Basin / Eastern Shasta County-Carquinez Strait and Delta-
Central Sacramento Valley-Clear Lake/Southern Lake County-
Motherlode-Mountains Southwestern Shasta County to Northern Lake
County-Northeast Foothills/Sacramento Valley-Northern Sacramento
Valley-Shasta Lake Area / Northern Shasta County-Southern
Sacramento Valley-West Slope Northern Sierra Nevada-Western
Plumas County/Lassen Park.

&&