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2.
A thunderstorm in which the sun briefly appears in part of the cloud to produce an eerie glow.
We had a sunderstorm that lasted for about half an hour and the mountains in the distance started to look like Mordor.
by pentozali August 10, 2012
 
1.
A thunderstorm where the sun stays out the whole time.
Tim: DUDE! It was sunny the whole time it was storming today. There was lightning and everything!

Chase: We live in Virginia, man; we always have sunderstorms.
by Rhetorik April 20, 2009