Over 85 million people in central US at risk of severe weather outbreak

At least 15 states will be at risk of an outbreak of violent thunderstorms that will unleash everything from damaging winds to tornadoes on Friday, AccuWeather meteorologists warn. The area highlighted by forecasters is a massive swath of the country that extends from Texas to Alabama in the South to areas farther north such as Wisconsin and Michigan.

The AccuWeather forecast team raised Friday's risk of severe weather from moderate to a high level prior to the middle of the week, a sign of growing concern for the potential damage the storms could cause. On Friday midday, the forecast team further raised the threshold of severe weather to an extreme level for portions of of Iowa, Illinois, Missouri, Arkansas, Tennessee and Mississippi. The extreme level is reserved for the few top severe weather events of the year.

"While all modes of severe weather are likely during Friday's outbreak, there is a likelihood of widespread damaging winds from the storm with at least several tornadoes likely to be on the ground," AccuWeather Chief On-Air Meteorologist Bernie Rayno said. "The storms will move along at a fast pace."

The forward speed of the storms may be between 40 and 60 mph, which means there may be little time to take shelter. The area forecasters say is under a high risk extends from parts of eastern Iowa and southwestern Wisconsin to portions of northern Arkansas and western Tennessee.

According to the National Weather Service's Storm Prediction Center, more than 85 million Americans are at risk of some form of severe weather on Friday.

Major cities that are likely to be hit with severe thunderstorms capable of generating a tornado include St. Louis, Chicago, Indianapolis, Little Rock, Arkansas, and Memphis, Tennessee. As the storms approach and push through the major metro areas, Federal Aviation Administration officials will likely issue ground stop orders on all flights.

In addition to the likelihood of damaging wind and the possibility of a tornado in the strongest storms, there is the likelihood for large hail, frequent lightning strikes and brief torrential downpours as well. Hail to the size of baseballs and softballs can cause significant destruction of property.

"The squall line storms will approach and swing through the Chicago metro area from 7-10 p.m. on Friday, which is an extremely busy time for airlines and vehicle traffic as people begin their weekend journeys and end their weekday activities," AccuWeather Meteorologist Brandon Buckingham said. However, there will be locally severe storms with torrential downpours, hail and perhaps an isolated tornado beforehand in the Windy City.


The severe storms will likely push through St. Louis on Friday afternoon but may not hit Memphis and Indianapolis until after dark. Potent thunderstorms are likely to swing through Detroit and Nashville late in the evening. By daybreak on Saturday, the line of thunderstorms will approach parts of the central and southern Appalachians.

As strong jet stream energy high above the ground interacts with surging warm air and moisture from the Gulf of Mexico, explosive thunderstorm development will take place during the midday hours over the western portion of the Mississippi Valley region on Friday. As the storms grow in number and intensity, they are likely to form a solid line, sometimes referred to as a squall line.

Before any squall line forms, some individual storm cells are likely to rotate. It is these discrete storms that will bring the greatest risk of tornadoes. But even after a squall line develops, individual thunderstorm cells within the line, and any storm that forms ahead of the advancing line, can spawn a tornado.

The risks of tornadoes, damaging straight-line wind gusts and torrential downpours will extend well beyond the daylight hours on Friday as the storms advance across the lower Great Lakes and the Ohio and Tennessee valleys prior to reaching the western slopes of the Appalachians.

The intensity of the storms after dark on Friday will raise the risk of injury and fatalities, as evidenced by the deadly tornado that struck Rolling Fork and Silver City, Mississippi, last week. Both communities are on the edge of Friday night's potential severe weather zone.

Forecasters urge residents and visitors in the path of the storms to keep up to date on weather bulletins through the nighttime hours.

Even where tornadoes do not strike, the force of the wind in the storms will be strong enough to push over poorly rooted trees and break off large tree limbs. As a result, there could be widespread power outages, incidents of property damage and blocked roads. In addition, the winds could blow over trucks and significantly damage mobile homes.

For parts of Wisconsin, Iowa, Minnesota and Michigan, this is likely to be the first round of severe weather of the season. Experts urge people in the path of the storms to review severe weather procedures and have a plan of action in place prior to the arrival of any storms.

The fast-moving storms are unlikely to bring enough rain to renew flooding problems on the secondary rivers from much of the Mississippi Valley to the Ohio and Tennessee valleys. Many secondary rivers reached minor to moderate flood stages after last week's deluge but were already receding as of Wednesday evening. Still, some urban and flash flooding cannot be ruled out in poor drainage areas and along small streams.

Some secondary river flooding could occur from southeastern Minnesota to portions of central and southern Wisconsin and part of the Lower Peninsula of Michigan. A period of heavy rain is possible for locations where the ground is saturated from prior storms that dropped heavy snow during the winter

The same storm system responsible for the upcoming severe weather will produce a band of heavy snow and possible blizzard conditions from parts of the central Plains to the upper Great Lakes region from Friday to Saturday.

The severe storms will continue to press eastward through the Appalachians and a large part of the Atlantic coast on Saturday.

Along with the likelihood of potent thunderstorms, high winds, power outages and property damage can occur from southeastern New York and southern New England to the Carolinas, Georgia and part of northern Florida.

There is a likelihood for another significant outbreak of severe weather to occur over part of the central U.S. early next week.

A potent storm system will take a similar track from the southern Plains to the Upper Midwest spanning late Sunday to Tuesday.

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