Confidence is high in hot weather with widespread Major to Extreme HeatRisk next week. Breezy north winds and low humidity will bring fire weather concerns to the Sacramento Valley early next week. Excessive Heat Watch from Tuesday morning through Friday evening.

Key Points

  • Likely a major heat event next week impacting holiday outdoor events.
  • Elevated to critical fire weather conditions Monday thru Wednesday.


Modest warming trend expected through the weekend as the upper trough weakens over NorCal allowing high temperatures in the valley to inch back toward the century mark. Marine layer remains shallow (less than 1k ft deep), but enough to bring some local breezes and overnight cooling to the Delta and southern Sacramento Valley.

Strong short-wave forecast to clip far northern California on Sunday may bring a few thunderstorms along the Oregon border and over northeast California, but likely remain north of the STO forecast area.

Next week's heat wave kicks off on Monday as ensembles continue to show strong ridging building into NorCal from the eastern Pacific.

Heat Watch issued

Highs Monday will mostly be in the 100 to 105 range across the Central Valley with areas of breezy north wind and low humidity expected to result in elevated to critical fire weather conditions across portions of the Sacramento Valley.

Extended Discussion (Tuesday through Friday)

Significant heat wave projected through the extended period with the potential for records to be broken.

Extreme heat risk Tuesday through Friday

Strong upper high in EPAC is modeled to progress towards the West Coast through next week with a 598-600 DM high centered over CA by next Friday. 850 mb temps progged to rise from the upper 20s Deg C Tuesday into the lower 30s Deg C Thursday into Friday.

Triple digit heat will result in the Central Valley and portions of the foothills through the week. Max temps at or above 110 deg F possible in the northern half of the Sacramento Valley Wednesday could become more widespread through much of the Central Valley Thurs/Fri.

Little relief expected overnight with 70s to 80s in portions of the Central Valley and foothills.

Critical Fire Weather

Areas of gusty northerly wind Tuesday into Wednesday in the Central Valley and adjacent foothills could result in periods of critical fire weather conditions.