Grass Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

751
FXUS66 KSTO 302049
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
149 PM PDT Sat Aug 30 2025

.DISCUSSION...

.SYNOPSIS...
Above normal temperatures persist through the holiday weekend
with a pattern shift then expected to take hold moving into mid
next week. Primarily Moderate HeatRisk expected through Monday,
with some areas of Major HeatRisk in the Valley. An approaching
weather system will bring increasing thunderstorm chances to the
region Tuesday and Wednesday as temperatures trend more seasonable
form midweek onward.

&&

.KEY MESSAGES...

* Today - Monday:
 - Above normal temperatures expected with widespread Moderate
   HeatRisk and areas of Major HeatRisk in the Valley.
 - Probability of Valley High Temperatures > 100F: 40-70%
 - Dry weather persists with daytime humidity into the teens to
   low 20s.

* Tuesday - Wednesday:
 - Weather system tracks northward along the California coast into
   the middle of the week, bringing a gradual cool down and the
   return of periodically breezy onshore winds.
 - Slight (10-20%) chance of isolated thunderstorms as the system
   moves through.
 - Some uncertainty in the location of potential thunderstorm
   development, although highest chances at this time are
   expected across the mountains.

* End of the Week:
 - Broad troughing aloft expected to remain in place with slight
   variations in location and orientation.
 - Seasonable temperatures anticipated across interior NorCal as
   breezy onshore flow persists.

.Changes from previous forecast...
- Increasing potential for thunderstorm activity early to mid next
  week, although moderate uncertainty in the location of
  potential thunderstorm development at this time.
- Warmest temperatures of the next several days now trending
  toward Sunday and Labor Day for much of the region.

&&

.AVIATION...
VFR conditions and clear skies are expected over the next 24
hours. Winds will be generally 10kt or less. Cumulus build-ups
over the Sierra crest possible through the afternoon.

&&

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

$$