Shelf Cloud Over Eastern Wisconsin

July 14, 2004


Provided by: Jeff Last, NOAA/NWS
Summary authors & editors: Jeff Last

The above photo panorama shows an impressive looking shelf cloud (also known as an arcus cloud) as it moved across Waupaca and Outagamie Counties in eastern Wisconsin during the evening of June 13, 2004. Shelf clouds develops ahead of thunderstorms as dense, rain cooled air cuts underneath the warm, moist air in front of the storm. Although its appearance is threatening, and almost always precedes strong wind gusts, a shelf cloud isn't necessarily a precursor to severe weather. In the Green Bay area, heavy rain and as well as forceful winds accompanied this storm.

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