P8.8
The derecho of July 5, 1999 in Quebec: a rare event
Serge Mainville, EC, Ville St-Laurent, PQ, Canada; and R. Heroux and P. Vaillancourt
During the night of July 5, 1999, severe thunderstorms affected most of southern Quebec. A derecho was moving at 100 km/hr causing considerable destruction on its path. By definition, a derecho is any rapidly moving extratropical convective system that produces downbursts causing significant and widespread damage. It has some of the features of a mesoscale convective system (MCS), as well as some of the features of a squall line, yielding radar a critical role into identifying a detailed structure of the event.
This case study documents the evolution of the derecho and reviews the dynamic and thermodynamic factors leading to its formation. Furthermore, it gives a deeper insight into the associated shear pattern that is conducive to such a destructive event. Finally, as it is often the case with any significant severe event, it enhances the particular combination of parameters that makes the formation of derechos possible.
Poster Session 8, Mesoscale Convective Systems And High Wind Events
Thursday, 14 September 2000, 5:00 PM-6:30 PM
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