Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 250430
Area Forecast Discussion
National Weather Service Sacramento CA
830 PM PST TUE NOV 24 2015
A COLD PACIFIC STORM WILL CONTINUE TO BRING ADDITIONAL SNOW IN
THE MOUNTAINS EXTENDING DOWN INTO THE UPPER FOOTHILLS INTO
EARLY WEDNESDAY. MAINLY DRY AND COLD WEATHER EXPECTED
THANKSGIVING THROUGH THE REST OF THE WEEK WITH LINGERING FLURRIES
OVER THE SIERRA CREST.
A shortwave is along the coast north of the Bay Area this evening.
The models in general are indicating that it most likely will
continue to move south along the coast. Scattered snow showers
are expected to continue overnight in the Sierra Nevada.
The wave moves down along the coastal range and doesn`t really
penetrate inland to impact the northern areas or have a big impact
on the southern areas as well. It may bring a couple of inches of
snow down to around 3000 feet in Lake County late at night and
early morning hours. As it pushes inland it may bring an inch or
two of snow to areas south of highway 88 late tonight and early
Wednesday morning and some rainfall into the San Joaquin Valley
Another wave in Oregon will rotate southward tonight and may bring
some light snowfall over the northern mountains. As it continues
to rotate southward east of the crest it will likely bring snow
showers along the crest throughout the day. The remainder of the
interior should dry out with some morning chances over the San
The low should move just enough east to dry most areas out for
Thanksgiving...other than some light showers or flurries over the
higher elevations. Thursday morning will start out cold. Sky`s
should be mostly clear but there looks like there could be some
northerly winds staying up all night. Surface pressure gradient
increases over Oregon and the Great Basin wednesday night into
Thursday. Freezing conditions may occur in some places with the
best chances over the eastern side of the valley where winds will
likely be lighter. Ski resort areas look to start off in the
teens and only warm up into the 20s the next several days.
.EXTENDED DISCUSSION (Saturday THROUGH Tuesday)
Models continue the development of a Rex Block along the W Coast
late in the week...with some retrogression over the weekend as
an offshore secondary low gradually rotates towards the underside
(southern portion) of the block. A cold and showery pattern will
prevail over Norcal into Sat with the potential for freezing/near
freezing temperatures continuing in the Valley and very cold
temperatures in the mountains and mountain valleys dropping into
the teens and single digits. A limiting factor for the cold morning
temperatures will be mixing winds and cloud cover.
Drier wx is expected Sun/Mon as the Rex (low) is nudged Ewd by
the energy rotating around the base of the low and as this energy
lifts NEwd. Model differences later in the period (Mon/Tue) add
some uncertainty to the forecast with the GFS a little more
progressive in spreading short wave energy inland and the ECMWF
keeping it offshore. We continued the previous forecast blend of a
wetter/more progressive solution but would not be surprised to see
the amplified ridge (Omega block) pattern reform along the coast
keeping the region dry. In any event...Sun and Mon should be
mainly dry days with moderating temps. JHM
Across Valley TAF sites, mainly VFR conditions the next 24 hours,
except patchy MVFR/IFR conditions with fog in the morning. Over
the mountains, IFR/LIFR conditions will continue with scattered
snow showers through Wednesday. Winds will remain below 10 kt
Winter Storm Warning until noon PST Wednesday for West Slope
Northern Sierra Nevada.
Freeze Watch from late Wednesday night through Thursday morning
for Central Sacramento Valley-Northern Sacramento Valley.
Winter Weather Advisory until noon PST Wednesday for Motherlode.