Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Sacramento California
1025 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.



Strong short wave moving sewd across the pac northwest with strong
sinking/drying occurring over norcal overnite. Hourly lamp guidance
shows a little more radiational cooling occurring tonite and have
lowered some of the mins especially in the valley and colder mtn

Maybe more fog Mon morning than the past couple of the
hr3 shows near zero vsbys from around kcic swd to ksuu and mainly
along the west side of the valley where winds are forecast to be nearly

Cold and breezy/windy wx expected as energy from the Arctic Circle
which is currently near the California/Washington border drops swd into norcal
phasing with/reinforcing the pac northwest short wave as it drops swd into
norcal late Mon/Tue. This will bring mtn snow showers...breezy/windy
conditions...and the coldest air of the season through the end of
the year (a -2 to -3 anomaly over the nrn rockys and portions of the
pac northwest depending on the Standard pressure chart of interest.) In looks like the ol' polar vortex will ring out the old year
and ring in the New Year over a large portion of the Continental U.S.. jhm

Previous discussion...

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 California/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 west-east 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 County Warning Area except for a slight chance of light
showers for Shasta County mountains. Jbb



VFR sky clear conditions overnite...but areas of fog and possible IFR/LIFR
vsbys developing from kcic swd to ksuu and mainly west of I-5 between
10z-16z Mon. Conditions improving Mon afternoon.


Sto watches/warnings/advisories...


National Weather Service Glossary of Abbreviations