Grass Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

838
FXUS66 KSTO 082123
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
223 PM PDT Fri Aug 8 2025

.DISCUSSION...

.SYNOPSIS...
A warming and drying trend is expected to continue with
widespread Moderate HeatRisk Friday through the weekend.
Widespread triple digit highs are expected into Monday.
Temperatures return to near to slightly below normal by midweek
next week.

&&

.KEY MESSAGES...

*Today-Saturday:
 - Gradual warming and drying trend continues as Desert Southwest
   and East Pacific ridging amplifies.
 - Breezy north winds return late tonight into early Saturday over
   portions of the northern and central Sacramento Valley,
   primarily along and west of I-5.
 - Warming trend continues Saturday with widespread Moderate
   HeatRisk and widespread triple digit high temperatures in the
   Valley.
 - Probability of high temperatures > 100F on Friday:
   --Northern Sacramento Valley: 70-95%
   --Remainder of the Valley: 35-70%

*Sunday-Monday:
 - Temperatures warm above normal through the weekend, with
   accompanying Moderate HeatRisk across the Valley and foothills.
 - Probability of high temperatures > 100F:
   --Northern Sacramento Valley: 80-100%
   --Remainder of the Valley: 50-80%
 - Onshore flow near the Delta will continue to give some relief
   with the Delta breeze for the Delta and southern Sacramento
   Valley, including the Sacramento metro area. Areas not influenced
   by the Delta breeze may have elevated low temperatures over the
   weekend, so continue to practice heat safety through the weekend
   even at night.
 - With the heat and low humidity and periods of northerly winds,
   minor elevated fire weather conditions exist for the Northern
   Sacramento Valley through Sunday.

*Later Next Week:
 - The East Pacific ridge axis aloft looks to shift westward, with
   shortwave troughing from western Canada.
 - This will bring gradual cooling across interior NorCal with
   seasonable to below average temperatures and periodically breezy
   onshore flow returning.

.Changes from previous forecast...
- Forecast overnight lows have trended a little higher for this weekend.

&&

.AVIATION...
VFR conditions expected to prevail next 24 hours across interior
northern California. Sustained surface winds less than 12 kts at
TAF sites. West-southwest wind gusts 15-20 kts through the Delta
00z-12z Saturday.

&&

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

$$