Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 011630
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
930 AM PDT Wed Oct 1 2014
Dry and warmer weather this week as high pressure rebuilds. Breezy
to locally windy northerly winds today, decreasing Thursday.
Breezy north winds continue this morning as tight gradient has
developed over the western sac valley between surface high building
into the great basin and surface trough over the central valley.
Winds are gusting up to 30 mph in several valley locations. After
coordination with area national forests moist fuel conditions from
recent rains will mitigate critical fire conditions. High temperatures
will warm to a few degrees above normal. Main forecast challenge
for the day will be winds which are expected to stay just below
advisory levels. Current forecast is on track and will not make
Clear skies across early this morning as strong high pressure
begins to build across the region in the wake of Tuesday evening`s
short-wave that moved through. Water vapor imagery indicating a
large area of drying in the mid and upper levels of the atmosphere
over NorCal indicative of strong subsidence. Current temperatures
are mainly in the 30s and 40s in the mountains while the foothills
and valley are in the 50s and 60s.
Northerly surface pressure gradients have continued to steadily
increase overnight and are now over 11 mbs from KMFR to KSAC.
Breezy northerly winds have developed through the Sacramento
Valley early this morning. Strongest winds are presently along the
west side of the valley where gusts to around 30 mph are being
reported. Pressure gradients shift and become more easterly today
and tonight before weakening on Thursday.
Daytime temperatures will warm into the weekend as high pressure
continues to build along the west coast and surface flow becomes
light to moderate offshore as the thermal trough migrates closer
to the coast. Valley high temperatures are expected to be in the
90s over the weekend before dropping off a bit early next week as
high pressure weakens slightly.
Crisp overnight lows will develop in many areas later this week as
winds subside and a cool/dry airmass allows efficient radiational
cooling with the longer nights of autumn. Mountain valleys will
see sub-freezing temperatures and the Central Valley will see some
overnight lows down into the 40s.
.Extended Discussion (Sunday through Wednesday)
Strong, warm high pressure will continue to sit over Northern
California, bringing well above normal temperatures for the
weekend and into early next week. The peak of the heat looks to be
Saturday, before the ridge flattens out a bit for Sunday and
Monday allowing for a few degrees of cooling. Light north winds
will continue to dry out the region through Monday. Models are
hinting at a weak closed low off the coast early next week which
could bring some additional cooling for Tuesday.
VFR conditions next 24 hours. Mainly northerly winds surface
winds sustained 10 to 20 with gusts to 30 knots higher terrain and
west side of the Sacramento valley. Low level wind shear TAF sites
with winds northeast to 40 knots 1000 to 2000 feet agl. Winds
decreasing after 00z.