Monday, April 09, 2012

Puzzling Story In Morning Paper


There was a story in this morning's newspaper that was headed: "Fire danger may be less this year, say forecasters." Given the dryness of the winter, I wondered how this could be. It turns out that, according to the story, the drought has limited growth of grasses and related fire fuels in the Southwest. I suspect that this character has mesoscale /regional aspects to it, since the grasslands of southeast Arizona appeared quite green at the end of summer (at least around Sonoita).

However, what I found very surprising were the statements that the main reasons for the optimistic outlook was the prediction "...of a less windy spring." The article further stated that: "This year, the storm track is not dipping as far south, and the forests of the Southwest are not directly on a path that brings wind but no moisture, week after week." This forecast came from the interagency, Southwest Coordination Center for wildfires in Albuquerque.

I have no idea how this forecast was generated, but I do know that the Climate Prediction Center's (CPC) seasonal outlooks are not something that I'd bet much on. The winds across the Southwest are often influenced by many aspects of mesoscale features interacting with larger scales of both circulation and orography. The fire season will extend into July most likely, and I would think that a complicated mix of various weather and climate details, including how often and widespread favorable conditions for dry thunderstorms occur, will play out to determine the evolution of the wild fire season.


Speaking of CPC, the current outlooks for April-June are shown here - temperature above and precipitation below. All in all, a pretty dismal outlook that anticipates continued hot and dry weather over much of the country.


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