Significant pattern change underway; wetter & cooler conditions likely through at least mid-December

Weather West

It has been a pretty interesting autumn, weather-wise, across much of North America. Record precipitation and severe flooding were observed in the Pacific Northwest and British Columbia; meanwhile, record warmth and dryness occurred across much of the interior West and Great Plains. In California, autumn 2021 proved to be a major departure from recent years, as a record-breaking atmospheric river event in October doused much of the northern half of state with extremely heavy rainfall that accounted for more than the entire average precipitation for the entire autumn season in just 2 days. Aside from that October event, though, precipitation has been very low statewide and temperatures have generally been well above average (except for some Central Valley folks stuck under a persistent layer of tule fog most days).

The net effect of all of this: California saw pretty minimal autumn wildfire activity due to relatively high soil and vegetation dampness and a lack of strong offshore wind events. NorCal saw some modest/partial drought relief, although precipitation deficits have further risen in SoCal. Accumulated precipitation from September 1 remains somewhat above average across much of NorCal (thanks to the big Oct. AR), but near or below average elsewhere following a long, multi-week dry spell during most of November into early December.

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