Mill Creek, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

590
FXUS66 KSTO 281112
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
312 AM PST Sat Dec 28 2024



.SYNOPSIS...
Active weather will bring rain, mountain snow, and breezy to
gusty southerly winds into the weekend. Drier weather is expected
into next week with colder morning lows.

&&

.DISCUSSION...
Showers are beginning to move across Shasta County and the
northern Coastal Range early this morning as the next system
begins to enter the region. Conversely further south, patches of
fog and mist have developed around the Modesto and Stockton areas
leading to lowered visibilities. Moving a touch further north,
breezy southerly winds are being observed around the central
Sacramento Valley with gusts 25 to 30 mph from Chico to Redding.

Precipitation for this incoming system will be mainly over Shasta
County, the foothills, and mountains with snow levels above 8000
feet. This will limit any impacts to mountain roads. A few
isolated Valley showers are possible through Saturday with most
lower elevations see little to no rainfall. An exception to this
is the area around Redding, which could see more significant
precipitation between 0.5 and 0.75 inches.

On Sunday, yet another push of moisture will bring more rain,
gusty southerly winds, and colder air. Snow levels will initially
sit around 7000 feet late Saturday night before lowering Sunday
morning 6000 to 7000 feet before lowering again through the
afternoon to 5000 to 6000 feet. Currently there is a 60 to 80%
chance of snow accumulations exceeding 4.00 inches above 6000
feet. Winter driving impacts have trended a little higher, with
the latest forecast. As a result a Winter Weather Advisory has
been issued for locations above 6000 feet in the Sierra from 5 AM
to 8 PM on Sunday. Winds will also be fairly gusty along the crest
up to 55 mph.

Highest rainfall accumulations with this system will once again
be over Shasta County and the foothills/mountains. Southerly winds
will begin to pick up Saturday night across the northeastern
Sierra foothills and the northern Sacramento Valley with gusts 35
to 50 mph, before expanding further down south later Sunday
morning bringing gusts 35 to 45 mph around the Delta and just
north of Sacramento. This is a similar synoptic setup to what we
saw Friday night, though with a somewhat stronger surface pressure
gradient and stronger winds aloft. A Wind Advisory has been
issued for 10 pm Saturday to 2pm Sunday for the northern and
central Sacramento Valley and northeast foothills. There is also a
marginal chance (10-20%) for isolated northern Sacramento Valley
and northeast foothill thunderstorms Sunday afternoon behind the
frontal passage.

By Monday dry weather returns as the system exits to the east and
upper level ridging shifts over the area. This will lead to breezy
northerly winds flow through the Valley with gusts 15 to 25 mph.
Colder morning temperatures also return next week with Valley
lows dipping into the 30s. The NBM is highlighting a 30 to 60%
chance of lows less than 35 degrees on the mornings of Tuesday,
Wednesday, and Thursday in the Sacramento Valley. Be sure to
practice cold weather safety next week.

Please continue to check weather.gov/sto for the latest updates
and check quickmap.dot.ca.gov before you go this holiday season!


.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
Ensemble guidance indicates general agreement for interior
Northern California to remain under the influence of upper level
ridging that is projected to build mid next week. Patchy fog will
be possible each morning in the Central Valley. The National Blend
of Models (NBM) suggests daytime high temperatures in the 50s to
around 60 degrees in the Valley and foothills, with 40s and 50s
for many mountain locations over the extended forecast period.
Cold low temperatures are also projected for Wednesday morning, in
the mid to upper 30s for much of the Valley, Delta and foothills,
with a slight warming trend through the end of the week and into
the weekend. There is some uncertainty with the upper level
pattern for late next week and over next weekend, with some model
guidance indicating the potential for some precipitation chances
Friday into Saturday. The NBM shows a 30-60% probability of
receiving at least a tenth of an inch of precipitation over this
timeframe, with the best chances in Shasta County.

&&

.AVIATION...
Areas MVFR/IFR with local LIFR in low ceilings in the northern
San Joaquin Valley through 18z today and/or precipitation next 24
hours. Scattered precipitation generally north of I-80 through 05Z
Sunday. Snow levels above 8000 ft through 03z Sunday.
Southeasterly wind gusts 15-25 kts across portions of the Valley
through 03z Sunday, increasing up to 30-40 kts 03z to 22Z Sunday.
Over mountains, areas of southwest to west surface wind gusts to
30 to 40 kts 03Z Sunday to 00z Monday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 10 PM this evening to 2 PM PST Sunday for
Central Sacramento Valley-Northeast Foothills/Sacramento Valley-
Northern Sacramento Valley.

Winter Weather Advisory from 5 AM to 8 PM PST Sunday for West
Slope Northern Sierra Nevada-Western Plumas County/Lassen Park.

&&

$$