August 1, 2016 – Less hot temperatures have arrived! Forecast highs today and for much of this week will be in the 90s to near 100° across the Valley, which is right around normal for this time of year.
Short term discussion (Today through Wednesday)
Northern California is currently situated between high pressure centered over the Desert Southwest and a longwave trough situated over western Canada. Skies are mostly clear across the region, except the usual stratus along the Bay Area coast. With a marine layer running 2000 ft deep and fair onshore flow, temperatures across the region are running several degrees cooler than 24 hours ago.
Relatively little variation is expected this week across the forecast area, as temperatures will likely remain within a few degrees of normal. Expect highs in the 90s to around 100 degrees across the Valley, with 70s to 90s across the mountains. A shortwave trough will pass through the Pacific Northwest on Tuesday, and will likely bring locally breezy conditions over higher terrain and near the Delta.
The San Joaquin Valley Air Pollution Control District is continuing their Air Quality Alert for San Joaquin County and southward today.
Extended discussion (Friday through Monday)
A weak upper level trough will continue to linger over NorCal during the extended forecast period. The ECMWF and GFS vary in exact timing, but both suggest that some short waves could swing across our region on Friday and Saturday. This will bring some instability that could spark showers or isolated thunderstorms. However, it should be limited to far NorCal in Shasta county terrain and northward. As the trough lingers, daytime highs will be below average ranging in the mid 80s to mid 90s from Friday through the weekend. Higher elevations can see a return to the 60s and 70s.