655
FXUS66 KSTO 302035
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
135 PM PDT Mon Jun 30 2025

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


.DISCUSSION...

.SYNOPSIS...
Low chance for mountain thunderstorms through mid-week. Lightning
on dry fuels may lead to easier fire starts. Otherwise warm and
dry weather continues with periodically breezy onshore winds.
Widespread Moderate HeatRisk persists into the middle of next
week. Quiet and cooler end to the week.

&&

.KEY MESSAGES...

* Early to Mid Week:
 -Above normal temperatures persist through Wednesday with
  widespread Moderate HeatRisk, although increased onshore flow
  brings some relief to the Delta vicinity
 -Slight (10-30%) probability of thunderstorms through Wednesday
  during the afternoon and early evening hours across the
  mountains of interior NorCal. Highest thunderstorm probabilities
  over the northern mountains on Monday-Tuesday. Thunderstorm
  chances expand farther south into the Sierra by Wednesday.
 -Lightning on dry fuels may lead to easier fire starts. A Red
  Flag Warning has been issued for the northern Coast Range,
  Shasta County mountains and Burney Basin from 11 AM - 8 PM
  Tuesday.

* Late Next Week:
 -Quiet weather late week with temperatures becoming seasonal to
  slightly below average
 -Coolest day will be Friday

.Changes from previous forecast...
 -No major changes in the forecast


&&

.AVIATION...


VFR conditions prevail across interior NorCal next 24 hours.
Surface winds 12 kts or less, except in the Delta vicinity where
southwest gusts 20 to 25 kts are expected through 14Z Tuesday.
Isolated mountain thunderstorms possible across northern/central
Sacramento Valley and surrounding terrain through 10z Tuesday.
&&

.STO WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 8 PM PDT Tuesday for Burney Basin and
Northeast Plateau in Shasta County Including Northwest Lassen NF
north of Lassen NP-Eastern Mendocino NF-Eastern Portion of
Shasta/Trinity NF-Northern Sierra Foothills from 1000 to 3000
Ft. Includes portions of Shasta-Trinity and Butte Units-Northern
Sierra Including Lassen NP and Plumas and Lassen NF/S West of
the Sierra Crest (West of Evans Peak-Grizzly Peak-Beckworth
Peak)-Southeast Edge Shasta-Trinity NF and Western Portions of
Tehama-Glenn Unit.

&&

$$