Area Forecast Discussion
Issued by NWS Sacramento, CA
FXUS66 KSTO 242242
Area Forecast Discussion
National Weather Service Sacramento CA
342 PM PDT Mon Oct 24 2016
Wet and unsettled weather will occur this week as several weather
systems transit the area.
A cold front is passing through northern California, with a band
of precipitation, currently located north of I80, and west of the
Sierra. Rainfall amounts so far total up to around an inch over
northern Shasta County, about a quarter to half inch over the
eastern side of the Coastal Range, and about a tenth to a quarter
of an inch over the northern Sacramento Valley. This band will
continue to shift south and east, reaching the northern San
Joaquin Valley by early evening. This precipitation will continue
overnight, moderate at times. Amounts will decrease south of I80
will be less as the front weakens. The heaviest rainfall amounts
are expected over the Feather River Canyon, where totals could
reach several inches by the end of the day Tuesday. Precipitation
rates will decrease in the afternoon, with lingering showers in
the evening. Snow levels will be above major pass levels, with
some snow accumulating at high elevations such as Lassen National
Park and seasonal passes.
Some breezy winds have developed this afternoon over the northern
Sacramento Valley and adjacent foothills. A Wind Advisory from 2
pm to 9 pm for those areas, sustained winds 15 to 25 mph, locally
gusting to 40 mph. Winds should peak by late afternoon, then
decrease in the evening.
Later Tuesday and Wednesday, we there will be a break before the
next system. Upper level ridging develops, shifting the
precipitation northward. Moist southeast flow ahead of the next
trough will bring in widespread precipitation over the area
Thursday, increasing late in the day and overnight. This will be
moist, subtropical air, some originating from the remnants of
Hurricane Seymour. This will keep snow levels high, so it will
mainly be a rain event, with gusty southwest winds over mountain
.EXTENDED DISCUSSION (Friday THROUGH Monday)
Unsettled weather for the end of the work week into the weekend.
The GFS, European, and Canadian models are in surprisingly good
agreement handling the entrainment of moisture from current
Hurricane Seymour into the westerlies. The odds of precipitation
are good across the region Thursday night into Friday, but the
amount of rainfall is currently highly uncertain.
Some residual moisture looks to keep showery weather going across
portions of Northern California Saturday. Models are coming into
better agreement with another wave on Sunday. A respectable amount
of precipitation is now forecast with that system, with snow
levels lowering below mountain pass level. Showers are likely to
continue into Monday.
VFR/MVFR conditions across the region today as a weather system
passes through the region. These conditions are likely to
conntinue tonight and into Tuesday as weather becomes showery.
South winds 10 to 20 kts with local gusts up to 35 kt will
diminish to 5 to 15 kts tonight and Tuesday.
Wind Advisory until 9 PM PDT this evening for Central Sacramento
Valley-Northeast Foothills/Sacramento Valley-Northern Sacramento