Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 222100
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
200 PM 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 continues to lift northeastward through
Northern California this afternoon. This system is interacting
with the remaning monsoonal moisture aloft and has spread
sprinkles to light rain across portions of the Northern San
Joaquin and Sacramento valley so far today. A few stray lightning
strikes were detected near Auburn and Chico as well. Short term
guidance initially underestimated the instability/precipitation
generated from this event however the HRRR caught up to
observations by 18Z. Radar imagery has consistently shown
southwest to northeast oriented band of precipitation of light
precipitation stretching across Northern California this morning.
This line is forming along an air mass boundary formed by the
aforementioned upper level disturbance and should continue to push
north-northeastward this afternoon into evening. A secondary line
developed just south of the main band of precipitation.
Precipitation so far has been fairly light in this band, with most
stations recording a trace to around a tenth of an inch.
The upper disturbance moves out of the area overnight. Winds
become breezy through the Delta and over the mounatins tonight
into Wednesday as the pattern shifts. The atmosphere dries out by
midweek and leaves behind a more stable atmosphere under southwest
flow aloft. Temperatures warm to above average for Thursday and
Friday after skies clear and high pressure backbuilds from the
desert southwest. Triple digit temperatures are possible in the
latter half of the week.
.Extended Discussion (Saturday through Tuesday)
High pressure ridge building in from the Desert Southwest will
result in above normal temperatures through the weekend and into
early next week. Portions of the Central Valley will likely be
reaching 100+ temperatures during this timeframe. There may be
enough onshore flow through the Delta to keep Delta Breeze-
influenced areas just below the triple-digit threshold.
Medium-range models continue to suggest monsoonal moisture
advecting northward. At this stage, a slight chance of
thunderstorms will be possible south of Tahoe on Sunday, with
perhaps a more widespread chance over the Sierra on Monday.
Mainly VFR conditions expected the next 24 hours, with scattered
mid to high clouds over the area. Isolated SHRA with a slight
chance of TS will be possible generally north of KCIC through
Across the Valley, south to west winds 5 to 15 kt will continue
through Wednesday. Near the Delta, southwest winds 15 to 30 kt
will be possible through Wed.