Ohio Valley derecho confirmed from Monday night
(WHSV) - The Storm Prediction Center has confirmed the powerful wind storm Monday night across the Ohio Valley as a derecho. In addition to hundreds of reports of wind damage, there were a few tornadoes as well:
The strongest wind gust in this derecho was 98mph in Fort Wayne, Indiana. This storm moved toward the Mid-Atlantic but it did weaken as it arrived by Tuesday morning in our area. This is why derechos are classified as one after the event occurs because of specific criteria.
Now there was also another cluster of storms with damage through parts of West Virginia and SW Virginia but that was not part of this derecho.
Since the Mid-Atlantic derecho of June, 2012 it seems like every summer there’s a rumor of another derecho. So what is a derecho and how often do these happen?
A derecho is not a single severe storm, and a derecho isn’t just a small cluster of severe storms. A storm complex, also called an MCS or a Mesoscale Convective System can form, often in the summer. So you’ll need an MCS to form, travel 240 miles or more and have severe winds along most of the path of the complex.
A derecho is going to be a widespread, long-lived thunderstorm complex with high winds that’s often fast moving. According to the National Weather Service, “By definition, if the wind damage swath extends more than 240 miles and includes wind gusts of at least 58 mph or greater along most of its length, then the event may be classified as a derecho.” Typically you would also have several extreme wind gusts of 75mph or greater at times through the path.
A derecho is going to likely have severe thunderstorm warnings along the leading edge of the thunderstorm complex. It can produce tornadoes but more so this is a straight-line wind event that will leave a damage path for 240 miles or longer.
On radar the tell tale sign of high winds along the leading edge is the bow shape the storm complex takes on, also called a ‘bow echo.’
A common summer pattern is called the ‘ring of fire’ where high pressure is situated across the center of the United States.
So often what happens is storms develop along the periphery of high pressure and the complex can follow the ridge.
MOST RECENT DERECHO
The most recent derecho in our area was May 14, 2018. There were power outages, trees down, and even flooding in parts of Page County. There was golf ball size hail reported at Afton Mountain (1.8″)
Here’s our local coverage of that event in 2018:
Wind reports exceeded 50mph across our area:
|Weyers Cave, Big Meadows (SNP)||53 mph|
|Luray, Fort Valley||46 mph|
|Waynesboro, Stanley||43 mph|
|Petersburg, Lost City, Upper Tract, WV||40 mph|
After the storms there was a nice display of mammatus clouds, the first time I’ve seen them locally:
Typically these kind of clouds form at the bottom of the anvil in a cumulonimbus cloud. It’s very common for these kind of clouds to be associated with severe thunderstorms but they don’t mean you’re about to experience a bad storm. Usually they will be after a storm or you can see them in the distance.
MOST MEMORABLE DERECHO
By far the derecho that most people remember is the 2012 June derecho. That storm complex traveled about 800 miles. That day, nearly 1200 reports were sent in for wind gusts of hurricane level strength which is greater than 74 miles an hour.
Twenty-two people lost their life in the June 2012 derecho with 2.9 billion dollars of damage as the derecho traveled 800 miles.
Many had never heard the term ‘derecho’ before this event. This is not a new term, it just happened to be the one that was picked up Nationally. Just like the polar vortex, it’s nothing new. These are meteorological terms you may have just never heard about this phenomenon before. In fact we locally, there was also a derecho in June of 2008.
Here’s more on the 2012 derecho:
HOW OFTEN DOES A DERECHO HAPPEN?
On average, Virginia can experience a derecho every 2-4 years. They are much more common across the Great Plains
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