Sunday, July 29, 2012

Officials State Storm Last Night Was a Supercell, Not a Tornado

From the Asbury Park Press:

While residents of Freehold woke up Sunday morning to extensive damage from a late Saturday night storm that looked for all the world like a twister had struck, weather officials have ruled out a tornado and fingered an uncommon supercell storm as responsible for all the damage.

“Supercell storms are mainly responsible for a lot of high-end severe weather,” said Jim Hayes, a meteorologist with the National Weather Service in Mount Holly.

“If it had been a tornado, there would be signs of a defined path and rotation on the ground,” said Kristin Kline, another meteorologist with the National Weather Service. “From all indications we’ve received as far as damage reports and radar, it looks to be straight-line wind damage. When winds descend from a thunderstorm, they hit the ground and travel horizontally outward from that center point.”

A supercell storm is a strong version of a thunderstorm that lasts for a couple of hours as opposed to the average thunderstorm length of 20 to 30 minutes, Hayes said.

The two weather conditions needed to produce a supercell storm are an atmospheric area with high instability and an increase in wind strength with altitude. These two conditions create a spinning storm that then powers itself, Hayes said.

Saturday night’s storm brought wind gusts as high as 60 to 65 mph between 10 p.m. to 10:30 p.m. in Monmouth County. That 30-minute span was the most damaging part of the storm, Kline said. Trenton-Mercer Airport registered a gust as high as 63 mph shortly after 9 p.m., she said.

Saturday night’s storm, which followed an afternoon storm that caused flooding in parts of Ocean County, originated in Bucks County, Pa., and then passed through Mercer County before it entered Monmouth County.

The Freehold area and borough of Eatontown suffered the brunt of the storm’s fury. The storm left more than 4,800 Jersey Central Power & Light customers in the Freehold area without power Sunday morning, according to the company’s power outage map.

Hayes recalled such a storm that hit the area between Toms River and Howell townships with reported 75 mph wind gusts just two weeks ago. But Hayes said supercell storms are more commonly found in the southern and central plains.

Photos From Asbury Park Press:




George Wright is a Certified Consulting Meteorologist for Wright Weather Consulting, LLC. George is also a meteorologist with ABC News and Cablevision News 12. Our website is WrightWeather.com.