Grass Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

294
FXUS66 KSTO 052048
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
148 PM PDT Fri Jun 5 2026

For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.


.KEY MESSAGES...

 -One last day of heat today, with Widespread Moderate HeatRisk.
  Cooling to near normal temperatures starts Saturday, dropping
  below normal early next week.

 -Dry weather except for chances of showers Monday and Tuesday,
  with the potential rainfall amounts beginning to decrease.

 -Breezy afternoon and evening onshore winds through Sunday with
  low humidity bringing a few areas of elevated fire conditions.

 -Potential increasing for gusty north winds and low humidity by
  late next week.

 -Temperatures trend above normal late next week.

 &&

.DISCUSSION...

...Main change to the forecast is decreasing rainfall amounts for
early next week, with generally light amounts expected. ...

...Today...
High temperatures this afternoon to be around 10 degrees above
normal, generally in the mid to upper 90s. Winds aloft will be
from the west northwest ahead of an approaching weather system
from the Gulf of Alaska, which this evening will bring an
increased delta breeze and breezy west to northwest winds over the
northern Sacramento Valley.

...Saturday and Sunday...
The approaching system will knock down the ridge over the weekend,
with notably cooler, near normal high temperatures. This means
mainly mid to upper 80s for the Valley, Delta and lower foothills.
Relative humidities remain low in the Valley and combined along
with gusty winds will bring a few hours of elevated fire concerns
in the north Sacramento Valley. Winds shift from northwesterly to
northerly on Sunday, with afternoon humidity in the Sacramento
Valley dropping to teens to single digits, bringing elevated fire
conditions. One mitigating factor is that winds peak in the
morning hours, so strongest winds are not expected to coincide
with the lowest humidity. This system will be dry, with breezy
wind and and cooler temperatures the main effects.

...Monday and Tuesday...

A secondary trough will move in behind the first for early next
week. High temperatures drop below normal, in the low 80s for the
Valley., This system has more moisture than the first, but recent
ensembles have trended less wet. There are chances for some
beneficial light rain in the foothills, mountains, and Valley.
Stay tuned as more details become know about this system.

...Wednesday through Friday...

Northerly winds increase as the trough shifts into the Great
Basin. These winds have been trending stronger recently. Gusty
winds and low humidity will bring increased fire weather concerns
across the Valley, Delta, and lower foothills especially
Thursday. Temperatures trend higher late in the week, with hints
of mid 90s to potential triple digit highs in the Valley by the
weekend.

&&

.AVIATION...
VFR conditions with clear skies at TAF sites over the next 24
hours. Northwest surface winds sustained 10 to 15 kts with gusts
15 to 20 kts in the northern San Joaquin Valley and Sacramento
Valley in the northern Sacramento Valley through 12Z Saturday. In
the Delta vicinity, west winds sustained 10 to 15 kts with gusts
to 25 kts through 18Z Saturday.

&&

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

$$