176
FXUS66 KSTO 072050
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1250 PM PST Wed Jan 7 2026

.KEY MESSAGES...

 - Weak, fast-moving system to bring snow showers to the mountains
   above 5000 feet; minor accumulations/impacts expected.

 - Dry weather with areas of morning fog and clouds starting again
   late week, with cold overnight/morning temperatures.

&&

.DISCUSSION...

...Rest of today and Thursday...
Low clouds lingering in the northern Sacramento Valley this
afternoon, keeping temperatures around 5-8 degrees cooler than
the rest of the Valley. The Gulf of Alaska trough is beginning to
dig further into the PacNW and is introducing weak moisture
columns to the NE foothills, Sierra, southern Cascades. Latest
hi-res models have increased convection threat across the NE
foothills and mountains, and the NBM has adjusted accordingly with
a 15% chance of convection through the rest of the day as the
trough moves through. Weak radar returns are being observed in the
foothills and mountains at the time of this writing, with mostly
light rain and mountain snow. This activity is expected to
increase as we go through the afternoon and evening, with light
accumulations of around 4-8" inches of snow above 5000 feet
through tomorrow morning.

As the trough moves out of the area, northerly winds will develop
which will be the strongest in portions of the northern San
Joaquin Valley. Overall wind gusts look to be around 15-25 mph,
with stronger gusts near Tracy and along I-5 and 205. Sky should
clear out tomorrow as well, with a few passing high clouds but
mostly sunny conditions should prevail across the Valley.

...Friday and Beyond...
North winds on the backside of the weak trough will continue,
although nothing impactful for our area is in the forecast. The
bigger story will be the cold overnight temperatures and the
continuation of foggy conditions. Some minor tweaks to the fog
forecast were made, based on continued confidence of upper level
ridging building in and keeping air somewhat stagnant this weekend
and beyond. The Climate Prediction Center keeps us at high
chances for continued dry weather into next week, as well as high
confidence in ensemble members keeping ridging aloft as our
dominant synoptic feature. Morning low temperatures are currently
forecast to be in the low to mid 30s in the Valley beginning
Friday morning and continuing into next week. Areas that are clear
or partially clear from morning fog will likely see frost develop
as well.

&&

.AVIATION...

Mainly VFR conditions today with scattered MVFR/IFR conditions
due to low clouds. A weak system will move through the area this
afternoon and evening bringing scattered light rain and mountain
snow (above 5000 feet) leading to scattered MVFR/IFR conditions
after 03Z Thursday, with a 15% chance of isolated thunderstorms
thru 08Z. Isolated FG and low stratus chances return to the
central/southern Sacramento and northern San Joaquin valleys
after 14Z Thursday, but north winds may limit development. Winds
will be light, generally below 12 kts through 00Z before north
winds increase after 17Z Thursday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$