Derechoes: One of Lance Bosart's Favorite Long-winded Topics

“Derechoes: One of Lance Bosart’s favorite long-winded topics”

Over the past few years, the term “derecho’’ has entered the public lexicon, largely as a result of some notable recent events, including the 29 June 2012 convective windstorm, which produced significant damage from Chicago to the east coast, and the 8 May 2009 convective windstorm, that produced significant damage from Kansas to Illinois. Research over the past 40+ years has shown that a variety of convective structures can be associated with such events, ranging from bow echoes with extraordinarily strong cold pools, as on 29 June, to bow-shaped systems that develop a deep, warm-core mesovortex, somewhat similar to a tropical storm, as on 8 May. Such studies have also helped clarify the local-through-synoptic scale environments conducive to their development, for instance, noting the association with very large CAPE and modest shear. Convection allowing simulations have also recently shown surprising skill in predicting such events, sometimes 24-48h in advance. Throughout this time, Lance has been one of the key motivators for the study of such events, and he and his students have been among the foremost contributors to establishing the related synoptic connections (for instance, have you ever heard the term “ridge roller”?). In this talk, I will attempt a blow-by-blow review of what we think we know about derechoes, with special emphasis on Lance’s contributions therein, and will also offer some thoughts on future research needs.