Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 081151
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
351 AM PST Sun Dec 8 2013
A very cold airmass will remain over Northern California through
at least midweek, bringing overnight hard freeze conditions each
Satellite imagery shows Northern California under dry northerly
flow between a longwave trough over the Rockies and high pressure
in the eastern Pacific. Mostly clear skies are being observed
across the region, although there are some high clouds off the
coast in association with a weak shortwave. Temperatures have
cooled off below freezing across the forecast area, although light
offshore breezes are keeping radiational cooling from reaching
its maximum potential.
The aforementioned offshore shortwave will remain off the coast,
diving southward toward Baja California over the next 24 hours. As
such, benign weather is expected to continue through the next few
days. Temperatures will remain well below normal as northerly flow
continues to pump cold Canadian air southward. Through at least
midweek, overnight conditions will likely remain similar as they
were this morning. Sub-freezing conditions will continue, but
drainage winds will likely keep temperatures from plummeting to
their maximum potential.
Some Record lows for Dec 8th Sacramento 27/2009, Sac Exec 23/2009,
Stockton 22/1978, Modesto 25/2009, Redding 20/1972,
Red Bluff 19/2009.
Some Record lows for Dec 9th Sacramento 23/1932, Sac Exec 21/1972,
Stockton 23/1972, Modesto 22/1972, Redding 21/1972,
Red Bluff 20/2009.
.Extended Discussion (Thursday through Sunday)
Models continue to show little run to run consistency with
handling of waves moving into the EPAC ridge during the extended
period. One trough may impact the region late Thursday into
Friday, but models diverge significantly so not much certainty in
what will happen. Have trended toward the drier ensembles with
only a slight chance of precip in the forecast.
General VFR conditions expected the next 24 hours as high pressure
rebuilds and dry northerly flow settles in. The exception will be
the northern San Joaquin Valley where areas of MVFR with local IFR
VSBYS will be possible through about 17Z. Northerly winds 5-15 kts
develop in the Sacramento Valley by this afternoon and continue
tonight. Easterly winds 15-30 kts develop tonight.
Hard Freeze Warning in effect until 8 am PST Tuesday for the
Sacramento Valley, Delta Region, Northern San Joaquin Valley,
Clear Lake/Southern Lake County, Northeast Sierra Foothills, and