156
FXUS66 KSTO 171921
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1221 PM PDT Fri Oct 17 2025

.KEY MESSAGES...

 - Dry weather with near normal temperatures across the region
   this weekend through much of next week

 - Locally breezy north to east winds on Monday behind a weather
   system passing to the north

 - Potential for a potent atmospheric river event late next week
   into next weekend (October 24-27)

.DISCUSSION...
Today through Sunday...Current GOES-West visible satellite imagery
illustrates mostly sunny skies across interior northern
California this afternoon with just a few high clouds passing
overhead. Dry weather and near normal temperatures prevail today
and over the weekend. Upper level ridging will continue through
Saturday before an upper trough crosses the Pacific Northwest on
Sunday. Chances for fog development are lower on Saturday morning
than they were today (generally 15-35% chance of 1/2 mile
visibility or less in portions of the Valley and Delta), however
some patchy fog in the Valley cannot be ruled out. Forecast highs
in the Valley are in the 70s to low 80s. Ensembles and clusters
have trended a little farther north with the upper trough for
Sunday and there is no precipitation or impacts expected from this
system.

Monday through Thursday...Behind the passage of the Pacific
Northwest trough, there will be some locally breezy north to east
winds. The strongest winds will be mainly along and west of
Interstate 5 in the Delta, the Sacramento Valley, the adjacent
Coast Range foothills and the Sierra, with gusts of 15 to 20 mph
on Monday. Little to no impacts are expected at this time, with
fire weather concerns minimal due to recent rain and mountain
snow. Much lighter northerly flow may linger into Tuesday morning.
Near normal temperatures are favored at the start of the week and
then temperatures gradually cool to slightly below normal later
in the week as ridging flattens.

Next Weekend...We are monitoring the potential for a potent
atmospheric river event late next week into next weekend (October
24-27) as an upper level trough deepens off the Gulf of Alaska and
approaches the West Coast. The Climate Prediction Center (CPC) is
indicating a risk for heavy precipitation, heavy mountain snow
and strong winds over this timeframe for much of northern
California. Stay tuned for more information as details on timing
and intensity of this storm become more clear. The dry weather
this weekend into next week would be a good time to clean up
leaves, gutters and drains ahead of the incoming storm to help
minimize potential flood impacts. /KH

.AVIATION...
Expect general VFR conditions are expected to prevail, with clear
skies and light variable winds for TAF sites. Confidence is low
for the return of fog tonight, with a slight chance (20%) of
visibility 0.5 miles or less 11z-16z for the Sacramento metro area
and into the Delta.

&&

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

&&

$$