Alleghany, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

305
FXUS66 KSTO 132016
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
116 PM PDT Tue May 13 2025

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

.Discussion...

.Synopsis...
Mountain showers and isolated thunderstorms continue through this
evening. Drier weather will then follow with seasonable
temperatures and occasionally breezy winds through the end of the
week. The next weather system then looks to arrive by the weekend,
bringing mountain/foothills thunderstorm chances Saturday,
followed by gusty and drying north winds Sunday into next week.
Resultant elevated fire weather conditions are anticipated Sunday
and Monday throughout the Valley due to the gusty winds and
expected low relative humidity.

&&

.Key Messages...

* Today:
 -Mountain showers and isolated thunderstorms continue as a
  weather system exits.
 -15-35% probability of isolated thunderstorms today, highest
  chances across Sierra/southern Cascades and adjacent foothills.
 -10-20% probability of 2" snow along the Sierra above 6000 feet,
  primarily from Interstate 80 southward.

* Mid to Late Week:
 -Dry weather returns, with generally seasonable temperatures and
  occasionally breezy winds.
 -Areas of Minor HeatRisk in the Valley.

* Saturday:
 -Weather system begins to drop southward from Pacific NW.
 -15-35% probability of isolated thunderstorms, highest chances
  across the northern Sacramento Valley, Sierra/southern Cascades,
  and adjacent foothills.
 -Temperatures cooling to near normal, with breezy winds
  throughout the day.

* Sunday - Monday:
 -Current ensemble trends indicate the expected weather system
  following an inside slider trajectory through the region.
 -Gusty north to east winds expected to develop Sunday and Monday
  as this system progresses.
 -Probability of gusts 40 mph or higher:
 --Sunday: 40-70%, highest along and west of I-5 in the Sacramento
  Valley.
 --Monday: 30-50% across the northern/central Sacramento Valley
  and Delta.
 -Elevated fire weather conditions Sunday and Monday due to the
  combination of gusty northerly winds and low relative humidity
  in the Sacramento Valley.

.Changes from previous forecast...
 -Shower and thunderstorm chances increasing for Saturday
  afternoon/evening.
 -Increasing likelihood of gusty north winds and at least elevated
  fire weather conditions developing Sunday and Monday.

&&

.AVIATION...
VFR conditions across all TAF sites next 24 hours. Surface winds
generally less than 12 kts. Local northwesterly wind gusts up to
15-20 kts across the northern San Joaquin Valley until 03z
Wednesday. There is a 15-35% chance of isolated thunderstorms
across the Sierra foothills and mountains until 06z Wednesday,
with periods of MVFR conditions. Gusty and erratic winds near
thunderstorms. Local northerly wind gusts across portions of the
Sacramento Valley 15z Wednesday - 00z Thursday.

&&

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

$$