Do You Recognize These Clouds?

Everyone has seen unusual looking clouds during their lifetime.

Some clouds are beautiful, others are scary-looking.

Stephanie Post, a severe weather spotter who lives in Kenosha County, took some great pictures of a shelf cloud as it approached and passed over her neighborhood.

Below are her pictures:

shelf cloud 1  shelf cloud 2  shelf cloud 3

For some people, her pictures show the beauty of clouds, while for other folks the clouds look scary.

Shelf clouds are found on the front side of thunderstorms, and are best-devleloped on the front side of a line of thunderstorm cells (squall line).

Shelf clouds look like a snowplow at times, and are indicators of an approaching thunderstorm downdraft which contains rain, hail, and gusty winds.  The strongest of the downdrafts are entitled "downbursts."  A downburst less than 2.5 miles in diameter is called a micro-burst.  Downbursts larger than 2.5 miles in diameter are called macro-bursts. Downbursts usually have moderate to heavy rains, may contain hail, and also may generate straight-line wind gusts of 100 to 150 mph.

Low-hanging, non-rotating, dark, cloud fragments may be attached to the shelf cloud that briefly resemble funnel clouds or even tornadoes.  We call these "scary-looking clouds (SLC)." Unfortunately, SLCs generate false reports of funnel clouds and tornadoes. True funnel clouds or true tornadoes are not common on the front side of thunderstorms.

Additional information about SLCs can be found at this link... http://www.crh.noaa.gov/mkx/?n=scary-clouds



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