732
FXUS66 KSTO 041927
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1227 PM PDT Mon May 4 2026

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


.KEY MESSAGES...

 - Widespread showers and isolated thunderstorms today. Best
   chances for thunderstorms exist over the mountains and
   foothills.

 - Cooler temperatures and thunderstorm chances linger into
   Tuesday, with drying conditions midweek.

 - Hot and dry conditions are expected to develop end of the week
   and into next weekend, with Minor and Moderate HeatRisk


&&

.DISCUSSION...

...Today through Tuesday...

Latest RADAR shows scattered showers moving over the area this
afternoon. Precipitation will be generally light but there may be
a few pockets of moderate rainfall at times. Thunderstorm chances
return this afternoon, with the highest likelihood (20-25%)over
the mountains and foothills, however a few isolated cells moving
into the Valley cannot be ruled out. Additional rainfall
accumulations of 0.25 to 0.75 inches are expected over the
central/southern Sacramento Valley and foothills, with 0.75 to
1.50 inches over the Sierra through Tuesday. South of Highway 50
there will be chances for snow through Tuesday, with minor
accumulations 2 to 5 inches along the highest peaks. Snow levels
are expected to remain above 8000 feet.

Lingering showers will move over the mountains and foothills on
Tuesday, with a 10-15% chance of thunderstorm development in the
afternoon/early evening. Temperatures through Tuesday will be on
the cooler side across the area, with highs in the 70s on Tuesday.


...Wednesday through Sunday...

Conditions dry out as we move into Wednesday and continue into
the weekend. Ensembles continue to favor upper level ridging
building over the western United States late this week and into
early next week. Temperatures gradually warm through midweek,
climbing well above-normal by the weekend. Minor HeatRisk is
expected across the Valley Wednesday, but becomes more widespread
into the foothills and mountains by the end of the week. Areas of
Moderate HeatRisk are expected in the Valley by Saturday,
expanding to include the foothills by the weekend. The NBM
currently indicates a 70-95% chance of high temperatures greater
than 90 degrees in the Valley Saturday and Sunday. Be sure to
hydrate and practice heat safety.

Minimum RH values trend lower through the week as well, dropping
into the 20s and teens by the weekend. This will coincide with a
period of breezy north winds that develops on Saturday which could
lead to elevated fire weather conditions in the central Sacramento
Valley. Forecast gusts are between 15 and 25 mph.

Looking into early next week, models are already hinting at the
potential for triple digit temperatures as riding amplifies over
the region. Currently, the NBM indicates a 50 to 70% chance of
100 or greater in the northern San Joaquin Valley and portions of
the central Sacramento Valley next Monday.

&&


.AVIATION...

Areas of MVFR/local IFR conditions in showers, isolated thunderstorms,
and/or low ceilings through Tuesday morning. Conditions will
gradually improve in the Valley by Tuesday afternoon and evening.
Lingering mountain showers or isolated thunderstorms Tuesday
afternoon, mainly over the northern Sierra and southern Cascades.
Gusty and erratic winds near thunderstorms. Otherwise, surface
winds generally 12 kts or less.


&&

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

$$