July 24, 2019 – Hot temperatures this week with widespread triple digit temperatures at the lower elevations. Hotter weather possible this weekend before cooling next week. A few late-day thunderstorms over the Sierra south of Lake Tahoe.


Clear skies cover the region early this morning as the trough moving through the PacNW has pushed moisture to the south and east of NorCal. Current temperatures range from the lower 50s in the mountain valleys to the 60s and 70s elsewhere.

Hot weather will continue through the remainder of the week. The Delta Breeze is expected to slacken today, but will reappear Thursday and Friday helping to moderate temperatures a bit in the Delta and Sacramento region.

Elevated moisture and instability has shifted well to the south and east of the area due to the trough passage to our north through the PacNW. This will be short-lived as the next short-wave is forecast to approach the West Coast on Thursday which will once again draw mid and upper level moisture and instability northward.

Most of the region will see an increase in cloud cover beginning later Thursday and continuing into Friday which will help to moderate temperatures a bit. The next chance for high-based convection looks to peak on Thursday night into Friday morning, and we’ll continue to monitor for possible introduction of slight chances for showers/thunderstorms into the forecast.

The short-wave lifts off to the east on Friday and the advertised heat is forecast to arrive over the weekend as the Desert Southwest high builds northwestward into NorCal suppressing the marine layer and bringing potentially the hottest weather so far this season.

Extended Discussion (Sunday through Wednesday)

Ensemble guidance is in good agreement that by Sunday an area of high pressure will be centered over southern California with ridging extending into the interior of NorCal. Have increased temperatures slightly on Sunday with Valley high temperatures ranging from 100- 110 degrees, roughly 10 degrees above average for most locations in late July.

Weak troughing returns to the west coast Monday which will act to push the high pressure back east and lower temperatures slightly for the beginning of next week. Temperatures return to near average by Tuesday with dry weather expected for the entire period.