Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 152200
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
300 PM PDT Tue Apr 15 2014
Breezy northerly winds tonight into Wednesday. A slight chance of
showers over the mountains Thursday afternoon into Friday and
possibly over the Northern Sacramento Valley Thursday night.
Temperatures above normal through Sunday then may cool to around
normal early next week.
.Short Term Discussion...
Upper level ridge nudging into Northern California from the
Eastern Pacific tonight into Wednesday. Temperatures this
afternoon in the 70s to low 80s in the valley with the coolest
conditions around the Delta with onshore flow and 60s to low 70s
in the mountains which is about 10 degrees above normal for mid April.
Low clouds dissipated around Vallejo at 11 am this morning and are
not expected to return tomorrow morning due to dry Northerly
winds. Northerly surface gradient increases to around 9 MB
Wednesday morning as surface high pressure builds into the Pacific
Northwest This will bring breezy northerly winds tonight into
Wednesday...especially along the North end of the Sacramento
Valley and the west side of the Central and Southern Sacramento
Valley. 925 MB winds around 25 kts Wednesday morning around 8 am
which may bring some stronger gusts. Little change in high
temperatures tomorrow compared to today as the Cold air advection
will be offset by downslope warming from the northerly winds. The
winds should decrease Wednesday afternoon with a weakening
The ridge shifts to the east Thursday as an upper level trough
approaches the west coast. The trough moves through the area
Thursday night into Friday. This will bring cooler temperatures
Thursday and Friday along with some clouds. There is some moisture
with this system with precipitable water values around an inch
Thursday afternoon into Friday. Showers are possible over the
mountains and possibly the Northern Sacramento Valley with this system
Thursday afternoon into early Friday and maybe even an isolated
thunderstorm along the Sierra Friday afternoon. Snow levels are
expected to be around 9000 ft. There is a little uncertainty in
the how quickly the trough will move through on Friday but it
will probably move out of the area by Friday evening.
.Extended Discussion (Saturday through Tuesday)
Generally dry and zonal flow over California through the weekend.
A weak shortwave trough will move through the PacNW late Saturday
which may potentially bring isolated showers over the Sierra
crest south of Highway 50. However, the wave will bring little
impact to our area. Temperatures will remain well above normal for
this time of year for the Central Valley.
After several weeks of quiet weather along the West Coast, a
change may be in store next week. All extended models are digging
a cold trough into NorCal sometime early next week...but
discrepancies remain on strength and timing. We`ll be keeping on
eye on this potential pattern change, particularly if models show
consistency in future runs. For now, have kept a chance of showers
for much of interior NorCal, along with cooler temperatures.
VFR conditions continue for interior NorCal for the next 24
hours. Generally light winds of 10 kts or less expected for
Central Valley TAF sites tonight. 25 kt SW wind gusts can
expected over Sierra ridges through around 03z, then decreasing
overnight. Northerly Valley winds will begin to increase over the
northern Sacramento Valley after 12z, spreading southward across
the area into the northern San Joaquin Valley by around 18z. Winds
will be strongest along the western side of the northern/central
Sacramento Valley, gusting locally 30 kts+ 15-22z.