Courtesy Dr. Daniel Swain, weatherwest.com
All signs continue to point to a notably hot, and possibly fiery, summer ahead across most of the West (including CA)
For several months, there has been a notable strong signal in the global “super-ensemble” (i.e., the “ensemble of ensembles” including predictions from all major global modeling groups) that this summer may be exceptionally hot across the western U.S. (and, really, across most or all of North America). The latest May update is no exception, and continues to point to a summer than may be much hotter than even (exceptionally hot) recent ones across most of the Western U.S. (and beyond).
Two details are of note: 1) There is a very high likelihood that Jul-Sep temperatures may end up in the hottest 20% of recent summers (i.e., even accounting for our climate-warmed baseline) and that yet another record hot summer is entirely possible in some areas, and 2) The anomalous warmth, particularly later this year from July onward, may reach closer to the California coast than it has the past couple of summers due to expectations that ocean temperatures will not be below average (and may end up warming to above average levels later in the season). So while the coast (as always) will still be cooler than inland areas this year, the seasonal gradient may be less pronounced than recent summers where record inland heat has been in great contrast to chilly and foggy conditions along the coast. It’s worth noting that May Grey and June Gloom are still likely, but after that, I do think this summer may be different than recent ones.
Accordingly, NIFC predictive services are now explicitly forecasting an above average fire season across most of California (away from the immediate coast), especially from July onward, and also across the Pacific Northwest, central and northern Rockies, as well as the Four Corners region. In other words: there are some striking signals pointing to widespread risk of a very active fire season across most of the West. The reasons vary a bit from location to location–in some cases, severe multi-year drought is raising risk in forests (interior SW); in others, the wet-to-dry whiplash transition expected later this summer (from wet antecedent conditions in 2024 or earlier, causing abundant grass and brush growth, followed by a dry spring and perhaps exceptionally hot summer) could be of concern in non-forest settings. In the Sierra Nevada and other higher mountain regions (including much of Colorado, and the Cascades in the PacNW), winter snowpack was quite respectable but melted very quickly this spring–leaving these upper elevations at greater risk of significant fire activity than solid peak season SWE numbers might otherwise suggest (especially in the context, once again, of a notably hotter summer potentially on tap).
In the short term, there continue to be good prescribed burning windows across CA and much of the West as the spring-to-summer transition is still underway. But there are some pretty strong signs that this summer has the potential to be a very active one, wildfire-wise, across the West–and that may be compounded by non-weather/climate-related considerations (see below).
