Tuolumne, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

187
FXUS66 KSTO 212039
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
139 PM PDT Sat Jun 21 2025

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

.DISCUSSION...

.SYNOPSIS...
An active, but predominantly dry weather pattern will keep windy
and cool weather through the weekend, introduce a return to near
normal temperatures and onshore flow, alongside slight mountain
thunderstorm chances into the early week ahead, followed by
potential for above normal temperatures mid to late week.

&&

.KEY MESSAGES...

* Red Flag Warning in effect through 9 AM PDT Sunday for Delta,
  Valley, and foothills locations below 3000 feet.

* Today - Sunday:

 -Elevated to critical fire weather conditions expected due to the
  combination of:
 --North to west winds gusting 30 to 40 mph through Sunday
  morning, then gradually decreasing into Sunday afternoon, and
 --Daytime relative humidity around 15-25% with only modest
  overnight recovery.

 -Seasonably cool temperatures expected, with Valley high
  temperatures in the 80s and 60s to 70s at higher elevations.

 -Please continue to practice fire safety such as, properly
  extinguishing any campfires, not driving over dry grass,
  checking your vehicle for chains or hanging objects that may
  cause sparks.

* The Week Ahead:

 -Gradual warming trend through midweek with temperatures
  returning to seasonal normal values. Valley high temperatures in
  the 90s with 70s to 80s expected at higher elevations.

 -Slight (10-20%) chance of isolated mountain thunderstorms Monday
  PM from Highway 50 southward.

 -Primarily dry weather then expected to follow as periodically
  breezy onshore flow develops late Monday-Tuesday.

 -Some uncertainty in upper level pattern late in the week, but
  current ensemble trends indicate further warming with areas of
  Moderate HeatRisk potentially returning by Friday.

.Changes from previous forecast...
 -Brief periods of elevated fire weather conditions possible into
  the early week ahead prior to the transition to onshore flow.

&&

.AVIATION...
VFR conditions persist at TAF sites next 24 hours with north to
west winds expected to remain breezy to gusty as well. Strongest
winds through the Valley and Delta gusting 25 to 35 kts at times,
gradually decreasing after 15z Sunday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 AM PDT Sunday for Carquinez Strait and
Delta-Central Sacramento Valley in Glenn, Colusa, Yuba, Northern
Sutter, and Butte County Below 1000 Ft-Eastern Mendocino NF-
Northern Sacramento Valley to Southern Tehama County Line Below
1000 Ft-Northern San Joaquin Valley in San Joaquin and
Stanislaus Counties Below 1000 ft-Southeast Edge Shasta-Trinity
NF and Western Portions of Tehama-Glenn Unit-Southern Sacramento
Valley in Yolo-Sacramento Far Western Placer, southern Sutter
and Solano County Below 1000 Ft.

&&

$$