Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 282254
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
254 PM PST Sun Dec 28 2014
Cold upper trough may bring a few showers mainly over the
mountains late Monday into Tuesday. Gusty north winds are likely
Tuesday into Wednesday. Frosty overnight lows continue.
Northern California remains under dry northerly flow between a
strong eastern Pacific ridge and deep trough over the Rockies.
Mainly clear skies and light surface winds allowed for strong
radiational cooling to occur again this morning, with most Valley
locations dipping down into the 30s and the mountains dropping
into the 10s and 20s.
Benign weather will continue today into Monday with dry northerly
flow continuing. Look for highs to reach the lower to mid 50s
across the Valley these days, with 30s and 40s for the mountains.
These highs are within a few degrees of normal. Lows will also
remain in the 30s across the Valley, which is around to slightly
cooler than normal.
Water vapor satellite imagery shows an impressive, elongated vort
max stretching across western British Columbia down into Oregon.
This will be the next system to watch, as it may bring a few light
showers to parts of the forecast area, and light snow
accumulations across the mountains. However, more importantly, as
the upper low closes off Tuesday into Wednesday over CA/NV, it
will likely bring a period of gusty north winds across the Valley
and over the Sierra. The NAEFS ensembles continues to show a
highly anomalous W-E wind component, which historically has meant
very gusty higher Sierra winds along with a strong barrier jet
setting up along the western Sacramento Valley. This could lead
to downed trees and power line issues in the Delta region like
Fairfield, as strong northeast winds are opposite from the typical
breezy southwest flow.
.Extended Discussion (Thursday through Sunday)
High pressure dominates the extended weather pattern. Conditions
will still be breezy on Thursday morning with an enhanced pressure
gradient between the high and a low over the desert SW. But that
gradient will relax by Thursday afternoon. Temperatures will
climb Thursday to near normal under mainly fair skies and warming
airmass under the ridge. Most areas will see a little more warming
on Friday into Saturday as the ridge persists. A weak system may
brush far NorCal Saturday night into Sunday, but it won`t bring
much of an impact to our CWA except for a slight chance of light
showers for Shasta County mountains. JBB
VFR conditions next 24 hours with a few high clouds across the
north today. Light winds below 10 knots at TAF sites for the next
24 hours. Patchy fog possible again in portions of the Southern
Sacramento and Northern San Joaquin valleys for local MVFR/IFR
between 6z to 18z.