Caption: This movie of the derecho that affected the Eastern United States in late June 2012 was created by imagery from NOAA's GOES -13 satellite. It begins on June 28 at 1515 UTC (11:15 a.m. EDT) and ends on June 30 at 1601 UTC (12:01 p.m. EDT). The derecho's clouds appear as a line in the upper Midwest on June 29 at 1432 UTC. By 1602 UTC, they appear as a rounded area south of Lake Michigan. By 2132, the area of the derecho's clouds were near Lake Erie and over Ohio expanding as the system track southeast. By 0630 UTC, the size appears to have almost doubled as the derecho moves over West Virginia, Maryland, Pennsylvania and Virginia. At 0232 UTC on June 30 (10:32 p.m. EDT), the Derecho was over the mid-Atlantic bringing a 100 mile line of severe storms and wind gusts as high as 90 mph to the region. (Credit: NASA/GOES Project)

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According to NOAA's Storm Prediction Center web site, a derecho (pronounced "deh-REY-cho") is a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms. Damage from a derecho is usually in one direction along a relatively straight track. By definition an event is classified a derecho if the wind damage swath extends more than 240 miles (about 400 kilometers) and includes wind gusts of at least 58 mph (93 km/h) or greater along most of its length.

These storms are most common in the United States during the late spring and summer, with more than three quarters occurring between April and August. They either extend from the upper Mississippi Valley southeast into the Ohio Valley, or from the southern Plains northeast into the mid-Mississippi Valley.

NOAA's GOES-13 satellite, which watches the movement of weather systems in the eastern half of the U.S., captured the expansion and movement of the derecho from its birthplace in Illinois. The satellite data was compiled and animated by the NASA GOES Project at the NASA Goddard Space Flight Center in Greenbelt, Md.

The movie begins on June 28 at 1515 UTC (11:15 a.m. EDT) and ends on June 30, 2012 at 1601 UTC (12:01 p.m. EDT). In the animation, the derecho's clouds appear as a line in the upper Midwest on June 29 at 1432. By 1602 UTC, they appear as a rounded area south of Lake Michigan. By 2132, the area of the derecho's clouds were near Lake Erie and over Ohio expanding as the system track southeast. By 0630 UTC, the size appears to have almost doubled as the derecho moves over West Virginia, Maryland, Pennsylvania and Virginia. At 0232 UTC on June 30 (10:32 p.m. EDT), the Derecho was over the mid-Atlantic bringing a 100 mile line of severe storms and wind gusts as high as 90 mph to the region.

To read more go to: www.nasa.gov/topics/earth/features/derecho.html

Rob Gutro