236
FXUS66 KSTO 271903
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1203 PM PDT Wed May 27 2026

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

.KEY MESSAGES...

 -Shower and isolated thunderstorm chances today through tomorrow,
  with the highest chances across the mountains and north of I-80.

 -Chances for light, high elevation mountain snow along the Sierra
  through tomorrow morning. Minor accumulations.

 -Trend toward drier and warmer weather end of the weekend into
  early next week, with Moderate HeatRisk potential.

&&

.DISCUSSION...

...Today through Saturday...

Upper level low continues to affect conditions across CA today and
through the early weekend. Current satellite we can see the low
pressure centered over the Great Basin, with northerly flow aloft
over CA. Scattered to broken clouds through the forecast area,
with showers and thunderstorms around Shasta county currently. We
expect further shower and isolated thunderstorm development
through the Sierra, foothills, and Valley this afternoon and
continuing through the evening. Best chances for thunderstorms
will be in the mountains and foothills, but due to the proximity
of surface low, higher sfc vorticity, instability and moisture
thunderstorms will also be possible in the Valley. A few storms
may be on the stronger side, with brief heavy rain, gusty winds,
and small hail. Near Shasta county, there will be a slight chance
(less than 20 percent) of a convergence zone to form bringing
training thunderstorms at times. We will continue to monitor
conditions throughout the day.

Temperatures will continue to be below average today and through
the early part of the weekend. Chances for isolated thunderstorms
and showers again tomorrow afternoon/evening, with lingering
chances in the mountains and foothills Friday and Saturday. A few
storms may be on the stronger side Thursday, with the potential
for gusty winds, brief heavy rain, and small hail.

...Sunday and onward...

The upper level low pressure system moves out of the Great Basin
end of the weekend and next week, bringing drier and warmer
conditions to the area. Temperatures will begin to reach back into
the 90s by early next week, with the potential for Moderate
HeatRisk for the Valley both Monday and Tuesday. RH values are
trending lower next week, but winds are remaining on the lighter
side at this moment. As we move through the end of the week we
will start to see a better picture of the pattern aloft and any
potential for increased winds and fire weather concerns for next
week.

&&

.AVIATION...

VFR conditions, with periods of MVFR is expected this afternoon as
showers and thunderstorms move through the region. Best chances
for showers and storms is around the Sacramento sites toward RBL
and RDD. MVFR conditions post 01-03z for Sacramento sites, RDD,
and RBL. Conditions should begin to dry out around 06-07z through
the end of the TAF period, with improving ceilings toward VFR. In
and around thunderstorms winds may become erratic at times.
Otherwise, winds will be on the lighter side.

&&

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

&&

$$