Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 101211
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
411 AM PST Tue Dec 10 2013
A very cold and dry airmass will remain over Northern California
through at least midweek resulting in clear skies and overnight
hard freeze conditions into Wednesday morning. Milder temperatures
along with some clouds will be possible by the end of the week.
Strong high pressure centered over the EPAC will continue to
result in dry weather across the interior of NorCal this week. A
short-wave trough will slide by later today and tonight and may
bring some clouds to the northern Sierra Nevada, but will
otherwise have little effect as the airmass over the region
appears too dry to support showers. The upper ridge is then
forecast to strengthen Wednesday before another wave approaches by
later Thursday. This one is expected to weaken dramatically as it
bumps into the ridge, but the northwest corner of the forecast
area may see a few showers while the remainder of the region stays
A mixed bag of temperatures across the region early this morning.
Much of the valley is running several degrees cooler than 24 hours
ago due to lighter winds as the northeasterly surface pressure
gradients have weakened considerably. On the other hand,
temperatures in the foothills and higher elevations above the
subsidence inversion are much warmer than 24 hours ago as the
general airmass modifies in response to the upper ridge overhead.
Forecast high temperatures the next couple of days will continue
to slowly trend upward in most areas due to the presence of the
ridge. However, areas that saw dramatic warming on Monday due to
the down-sloping northeast winds will be cooler as winds will be
much lighter the next few days.
.Extended Discussion (Saturday through Tuesday)...
The upper flow becomes northwesterly with a weak short wave trying
to break down the ridge somewhat Saturday night into Sunday.
However, the wave doesn`t succeed and the ridge keeps it`s hold
over northern California through Tuesday. Slowly rising 500 mb
heights will bring warming temperatures for most locations, with
normal or even above normal temperatures into next week. -JClapp
Light northerly flow in valley with little stronger northeasterly
winds down Sierra today. Dewpoints and humidity up from 24 hr ago,
may see isolated MVFR vis in haze and shallow ground fog in srn
Sac/nrn San Joaquin Valleys 12Z-16Z. -JClapp
hard freeze warning until 8 am pst wednesday carquinez strait
and delta...central sacramento valley...northern sacramento
valley...northern san joaquin valley...southern sacramento
hard freeze warning until 8 am pst wednesday below 2000 feet in
the clear lake/southern lake county...motherlode...northeast