Interesting Weather Information

Friday, March 1, 2013

The Long Life of the March 2, 2012 Supercells

Supercell thunderstorms are special animals.  They represent a balance between expending energy and taking energy in.  The imported energy is mainly water vapor. It condenses when lifted.  The heat liberated helps drive the supercell, sometimes for hours.

A non-descript thunderstorm has an updraft that is vertical. The lifted water vapor, condenses, raindrops grow then fall as torrential rain right  through the updraft. It's like pouring water down a chimney - the fire will go out. In the case of a non-descript thunderstorm the rain drops push  against the updraft and that toe-to-toe battle limits  the storm's life to between 15 and 45 minutes.

The supercell lives to be a senior citizen in t he world of thunderstorms. They have been known to persist for 12 hours because their updraft is tilted and the rain falls out ahead of the updraft. There is no battle between the rising air and the falling rain in a supercell. So ... it lives a long time.

The animation is from the Wilmington NWS NEXRAD Doppler Radar.  The arrow points to where the cells that would cause the tornadoes are first visible, then follows the storms.  The Paducah, KY radar saw the cells born in southeast Missouri. In the second time lapse the three supercells that caused the Holton, IN, the Crittenden-Piner-Fiskburg-Morning View and the Peach Grove - Moscow - Hammersville tornadoes are circled and magnified.

The total track length  was about 550 miles.

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