What is a derecho?A derecho is a type of MCS that produces widespread severe and damaging straight-line wind. They aren't as common as other types of MCS's and tend to feed on the warm and unstable airmasses produced during the summer months. A derecho, by definition, must produce a swath of severe wind (58 mph or greater wind gusts) and damage over a path of at least 240 miles. These systems last for hours and must have produced continuous damage with no breaks for more than a couple of hours. Typically they appear as a large bow-shaped band of showers and storms. The most cited example locally of a derecho is the "Mid-South Summer Storm of 2003," more commonly referred to simply as "Hurricane Elvis" which occurred during the morning rush hour on July 22, 2003.
June 11, 2012 DerechoAs seen in the radar animation of this particular storm system below, the derecho began over Missouri in the late morning hours. It dropped southeast through the Mid-South around mid-afternoon, then elongated and continued unabated through the Deep South, affecting Mississippi and Alabama before falling apart as it moved over the Gulf of Mexico. The total distance traveled was over 600 miles! As you can see, additional storms fired along the outflow of the derecho over southern Arkansas and eastern Oklahoma and Texas, which then became an MCS of it's own as it dove south over Louisiana in the wake of the derecho.
|Radar animation of the long-lived derecho of 6/11/12. Courtesy UA-Huntsville.|
Derecho ImpactsThe impact of the derecho is clearly shown below in the graphic of severe wind reports from Monday and Monday night. Over 300 reports of damage or measured wind of 58 mph or greater were recorded, though some were part of the additional MCS that formed over Louisiana and Texas or separate storms along the Atlantic coast.
|Severe wind reports (308) from 7am Monday through 7am Tuesday as received by SPC.|
|Just one example of hundreds in the Memphis area - a tree down in north Bartlett|
What was your experience from this derecho? Did you lose power and if so, for how long? Did you lose any trees or have other damage?
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