Early Fire Season for California

As I mentioned in my previous post, a combination of warm to hot temperatures, gusty offshore winds, low humidity levels, and abnormally dry vegetation would result in a high fire risk across much of California this week.  Several fires have already broken out in parts of northern California, namely in Sonoma County (north of San Francisco) and in the foothills of the Sierra well north of Sacramento.  These fires are not very large and are nearly contained, but it is quite early for numerous wildfires to develop - normally the fire season in California starts in June or July and peaks in September.  Smoke from the Panther Fire in the Sierra foothills north of Sacramento was clearly evident on satellite imagery this afternoon, with a plume of smoke being blown westward with the offshore winds.  The fires north of San Francisco are smaller and not producing enough smoke to be visible in this image.


The heat will continue across much of California for the next two to three days, with the warmest temps likely occurring at the coast on Thursday and inland on Friday.  A Heat Advisory is even in effect for the Bay Area, where afternoon temperatures may approach 90º in San Francisco and into the mid-90s inland.


The other big weather story is the very late season snow storm moving through the Rockies and Upper Midwest.  The Denver area received several inches of snow earlier today, and now areas from Nebraska north to Minnesota and Wisconsin are seeing snow or a rain/snow mix.  The snowiest May in Minneapolis was in 1946 when 3" was reported.  For the current storm system, some areas of eastern Minnesota may receive up to 6" of snow, which would easily break most May snowfall records for the region.  Radar imagery this evening from the Twin Cities shows that the heaviest band of snow is (so far) remaining just southeast of Minneapolis and the airport there (where the official snow measurements are taken).  The snow is generally moving to the northeast, so it remains to be seen whether this record can be broken.  Regardless, some areas will receive several inches out of this.  These late season, record type events are extremely difficult to forecast as well since there is so little precedent for them.  Forecasters weight climatology heavily when making most weather forecasts, so highly abnormal events give forecasters little to work with except the computer model runs.