Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Sacramento California
841 am PDT Tue Jul 22 2014

an upper wave moves over norcal today with showers and potential
thunderstorms. Then expect a warming trend Wednesday into the


Short term discussion (today through thursday)...
an upper level disturbance is lifting northeastward into northern
California this morning. This system is interacting with the
remaning monsoonal moisture aloft and has already spread sprinkles
across portions of the northern San Joaquin and southern
Sacramento Valley early this morning. A signal lightning strike
was also detected north of Auburn around 8am as well. Short term
guidance underestimated the instability/precipitation generated
from this event, so we are updating the short-term weather grids to
include a broader mention of shower and isolated thunderstorms in
the valley. Current radar imagery shows a narrow band of precipitation
stretching from San Jose to Auburn with a few scattered showers
over the central Coast, Lake County, and Chico as well. These
light showers should continue to move towards the northeast as the
upper distrance treks in that direction.

The upper disturbance moves out of the area overnight. The
atmosphere dries out by midweek and leaves behind a more stable
atmosphere under southwest flow aloft. Wind will likely be breezy
through the Delta and over the mounatins on Wednesday.
Temperatures warm to above average for Thursday and Friday once
skies clear and high pressure strengthens from the Desert Southwest.

Extended discussion (saturday through tuesday)

Ridging building in from the desert SW over norcal through the
extended period resulting in warming temperatures. Some triple
digit heat is possible in portions of the Central Valley by Friday
becoming more widespread over the weekend. Models showing
relatively dry atmosphere into the first half of the weekend but
show some monsoonal moisture advecting northward. The GFS/ec have
southeast flow aloft with an embedded wave over southern/western
Nevada on Sunday/Monday with a hint of monsoon moisture creeping up
the Sierra. The timing of any moisture surge is debatable at this
time, but the main theme is the increasing potential for another
round of a subtropical surge and resultant thunderstorm
development, mainly over the mountains, late in the forecast
period. Jclapp



General VFR conditions today with scattered mid clouds, though iso
rain showers/thunderstorms and rain possible over the coastal and northern mtns, and
extending into western and northern portions of the Sacramento
Valley. Southerly valley winds gusting to 20 kt north of i80, 18z-
06z. Delta breeze gusting to 30 kt. Ek


Sto watches/warnings/advisories...


National Weather Service Glossary of Abbreviations