Big River, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

382
FXUS66 KSTO 261946
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1246 PM PDT Tue May 26 2026

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


.KEY MESSAGES...

 - Cooler, unsettled weather this week with scattered showers and
   thunderstorms

 - Chance for light, high elevation mountain snow along Sierra
   tonight-Thursday morning

 - Warmer weather by this weekend, with Moderate HeatRisk
   potentially by Monday

&&

.DISCUSSION...

...Today through Saturday...

An upper low pressure system has already begun to descend upon
Northern California, bringing much cooler temperatures, showers, and
scattered cloud cover to the area. A few thunderstorms are
beginning to develop along the northern Sierra as well. This
system is tracking further south, faster than previous model runs,
resulting in increased scattered shower potential today through
Thursday. NBM and HIRES models continue to favor Shasta County and
the Sierra north of I-80 as the highest likelihood for
thunderstorm development today, with a nonzero chance in the
Valley/foothills. Thunderstorm chances expand to include the
entire Sierra Wednesdsay-Thursday. Snow levels will be at 7000
feet and above, but will slowly drop toward 6000-7000 feet late
tonight and into Wednesday. Areas south of Highway 50 in the
Sierra at the higher elevations have the best chances to see snow.
Accumulations are expected to be minor, but may result in slick
roads.

As the low meanders along the CA-NV border, wrap around moisture
will bring chances for lingering rain showers Friday morning
along with isolated thunderstorm potential on Saturday. Be sure to
stay weather aware this week, especially if traveling up in to
the mountains for recreation.

...Sunday and onward...

Drier weather with gradually warming temperatures as heights
begin to increase. We`ll still be underneath broad, weak
troughing pattern which will keep temperatures closer to seasonal
averages with breezy onshore flow on Sunday. Moderate HeatRisk
begins to creep into the area on Monday and Tuesday, remaining
mainly in the foothills and northern Sacramento Valley. There is
still uncertainty regarding how quickly ridging builds. If it
trends later in the week, this may lead to continued cooler
temperatures into next week.

&&

.AVIATION...

VFR conditions and scattered MVFR conditions are expected today as
a low pressure system moves through the area. Isolated MVFR due to
light rain and mist at times through 18Z, with a 15 to 20% chance
of isolated -TSRA in the foothills/Valley between 22Z today and
02Z Wednesday. Higher likelihood (25 to 35% chance) of showers
and thunderstorms over the mountains 20Z to 04Z. North winds will
be breezy at RBL and RDD with gusts 15-20kts until 23Z today.
Surface winds will generally be 12kts or less, but gusty and
erratic winds will be possible around any thunderstorms that
develop.

&&

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

$$