Severe Thunderstorms Head to Midwest, South, and Northeast

Josh Edelson/AFP/Getty Images
Josh Edelson/AFP/Getty Images

A widespread outbreak of severe thunderstorms could make for a tense couple of nights to welcome the unofficial start of spring in the Midwest and parts of the East Coast. Forecasters expect dangerous thunderstorms to develop in the Midwest on Tuesday night, February 28, and slowly make their way east before another round of storms flares up late in the day on Wednesday. Tornadoes, damaging winds, and large hail are all possible, though the greatest threat that communities face could be all of those hazards occurring at night.

This severe weather outbreak will follow a classic pattern that’s common during the spring. The fuse that will set off the atmospheric fireworks is a developing low-pressure system over the Plains that has made its way toward the Great Lakes today. Winds circulating around the low are funneling warm, unstable air north from the Gulf of Mexico, bathing the Mississippi and Ohio River Valleys with unseasonably muggy air. This soupy air serves as the fuel to power thunderstorms triggered by the lift from the low-pressure system and its fronts. Making matters worse is that strong winds through the atmosphere will help those thunderstorms turn severe. As of press time, tornado watches have been issued for Illinois and parts of Iowa, Missouri, and Arkansas.

The Storm Prediction Center’s forecast for severe thunderstorms on Tuesday, February 28, 2017. Warmer colors indicate a greater risk for severe weather. Image Credit: Storm Prediction Center

 
The severe thunderstorms will thump communities in several rounds, with each round carrying its own safety risks. The latest forecast from the Storm Prediction Center calls for the worst weather to unfold from Arkansas to Ohio during the evening and nighttime hours on Tuesday. Thunderstorms are bubbling up on the western part of the risk area and working their way east. Tornadoes are possible, and some could be on the stronger side. As the evening wears on and the cold front draws closer, these discrete thunderstorms should merge into a squall line, at which point the main hazard will transition to damaging straight-line winds. Small tornadoes are possible along the leading edge of the squall line.

The Storm Prediction Center’s forecast for severe thunderstorms on Wednesday, March 1, 2017. Warmer colors indicate a greater risk for severe weather. Image Credit: Storm Prediction Center

 
Wednesday’s storm threat looks a little more straightforward than what we’re likely to see on Tuesday night, but it’s no less dangerous. Meteorologists expect more squall lines to form along the cold front as it approaches the Ohio Valley and the Appalachian Mountains on Wednesday evening. The lines of storms could produce damaging winds and a few tornadoes as they sweep eastward. It remains to be seen how strong the storms will be once they cross the mountains—the steep hills and valleys often take the oomph out of approaching storms, but they could regenerate once they cross back over flatter terrain.

When we talk about severe thunderstorms, the term “damaging winds” refers to thunderstorm wind gusts that reach 58 mph or stronger, and “large hail” is a hailstone the size of a quarter or larger. We consider tornadoes “strong” when they cause damage that’s rated EF-2 or higher on the Enhanced Fujita Scale. It’s important to remember that damaging wind gusts can easily cause as much damage as a tornado, but over a much larger area.

Severe thunderstorms are dangerous any time of the day, but they can pose a greater threat to your life when they occur at night. You’re less likely to receive life-saving severe weather warnings at night when you’re asleep than you are during the day when you’re more aware of your surroundings. If you live anywhere expecting severe weather, make sure you have a way to be notified of hazardous weather at night. Most smartphones have a wireless emergency alert (WEA) feature that sounds an annoying (but useful) tone that could wake even the deepest sleeper when a warning is issued for your current location. Thanks to the widespread use of smartphones, wireless emergency alerts have saved countless lives in the past couple of years.

But, there’s a catch. In order for wireless emergency alerts to work, your cell phone has to be charged, and it needs to be able to receive a signal. It’s always a good idea to have a couple of backups just in case. A NOAA Weather Radio is a smart albeit slightly outdated investment to make. These devices are like smoke detectors for the weather. You can program a county’s unique code into the device and set it to sound a loud tone when a watch or warning is issued for the location(s) of your choosing. If all else fails, you can also leave your television or radio on loud enough that you can hear emergency alert tones if a warning is issued for your area.

What Is a Bomb Cyclone?

Maddie Meyer/Getty Images
Maddie Meyer/Getty Images

The phrase bomb cyclone has re-entered the news this week as parts of the central U.S. face severe weather. Mountain and Midwestern states, including Colorado, Nebraska, Wyoming, and South Dakota, all fall in the path of a winter storm expected to deliver tornadoes, hail, heavy snow, flooding, and hurricane-force winds on Wednesday, March 13 into Thursday. It seems appropriate for a storm that strong to have bomb in its name, but the word actually refers to a meteorological phenomenon and not the cyclone's explosive intensity.

According to The Denver Post, the bomb in bomb cyclone stands for bombogenesis. Bombogenesis occurs when a non-tropical storm experiences at least a 24 millibar (the unit used to measure barometric pressure) drop within 24 hours. Low pressure makes for intense storms, so a bomb cyclone is a system that's built up a significant amount strength in a short length of time.

This type of storm usually depends on the ocean or another large body of water for its power. During the winter, the relatively warm air coming off the ocean and the cold air above land can collide to create a sharp drop in atmospheric pressure. Also known as a winter hurricane, this effect has produced some of the worst snowstorms to ever hit the U.S.

The fact that this latest bomb cyclone has formed nowhere near the coast makes it even more remarkable. Rather, a warm, subtropical air mass and a cold, Arctic air mass crossed paths, creating the perfect conditions for a rare bombogenesis over the Rockies and Great Plains states.

Central U.S. residents in the bomb cyclone's path have taken great precautions ahead of the storm. Over 1000 flights have been canceled for Wednesday and schools throughout Colorado have closed.

[h/t The Denver Post]

Watch a Rare ‘Ice Tsunami’ Slam Lake Erie

Clean Lakes Alliance, Flickr // CC BY 2.0
Clean Lakes Alliance, Flickr // CC BY 2.0

A combination of freezing cold temperatures and high winds is creating an unusual phenomenon along Lake Erie. As KDKA reports, ice tsunamis are toppling onto lake shores, and many locals have been asked to stay inside and even evacuate their homes.

On February 24, 2019, the National Weather Service in Buffalo, New York issued a warning about dangerous wind gusts in the Lake Erie area. The service urged citizens to seek shelter indoors and avoid traveling if possible. Winds peaked at 74 mph earlier this week, the level of a Category 1 hurricane, and tore down trees and power lines throughout the region.

People who got close to Lake Erie during the windstorm witnessed a rare event known as an ice tsunami. When wind pushed ice on the lake's surface toward the retaining wall, the sheet broke apart and dumped massive ice chunks on the shore. The video below captures the phenomenon.

In some areas, the ice piles grew so large that roadways had to be closed. Residents of Hamburg, New York's Hoover Beach area were asked to voluntarily evacuate due to the encroaching ice.

Ice tsunamis, or ice shoves, are rare, but in some cases they can be life-threatening. In 2013, waves of ice shards from a Minnesota lake destroyed people's homes.

[h/t KDKA]

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