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

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.

nextArticle.image_alt|e
iStock
arrow
Weather Watch
Thanks to Desert Dust, Eastern Europe Is Covered in Orange Snow
iStock
iStock

Certain areas of Eastern Europe are starting to look a bit like Mars. Over the last few days, snowy places like Sochi, Russia have experienced an unusual snowfall that coated mountains in orange powder, according to the BBC.

The orange snow was the result of winds blowing sand from the Sahara east to places like Moldova, Romania, Bulgaria, Ukraine, and Russia. The sand mixes with precipitation to form orange-tinted snow. According to the BBC, the phenomenon occurs semi-regularly, turning snow orange about once every five years, but this year is especially sandy. As a result, skiers are navigating slopes that look like they're from a different world, as you can see in the video below from The Guardian.

The Sahara rarely gets snow, but when it does, the landscape can look somewhat similar, as you can see in this image of the Atlas mountains in Morocco.

Instagram is currently filled with photos and videos from Eastern Europe featuring the odd-looking snow. Check out a few samples below.

[h/t BBC]

nextArticle.image_alt|e
Jessica Kourkounis, Getty Images
arrow
Weather Watch
What Is Thundersnow?
Jessica Kourkounis, Getty Images
Jessica Kourkounis, Getty Images

The northeastern United States is dealing with its second major nor'easter in a week, with rain and heavy snow—and the associated power outages—cutting a path across the Mid-Atlantic and New England. But news of the adverse impacts of the snowstorm is being accompanied by an unusual buzzword: thundersnow. Thundersnow occurs during a thunderstorm that produces snow instead of rain. The mechanisms that produce rainy thunderstorms and snowy thunderstorms are largely the same, even if the air temperature is below freezing.

A band of snow can become strong enough to produce lightning through two processes known as convection and forcing. Convection occurs when an area of warm air quickly rises through cooler air above it. Convective snow is most common during lake effect snow events like those you’d find on Lake Ontario or Lake Erie, since the process requires extreme vertical temperature gradients that can result from bitterly cold air flowing over a warm body of water.

Forcing is slightly different. A strengthening low-pressure system involves fast, dynamic changes in the atmosphere, especially when one of these storm systems quickly gains strength. Such a fast-developing storm can cause large amounts of lift in the atmosphere, a process that forces air to swiftly rise like you’d see during convection. This creates intense bands of snow that can grow so strong that they produce thunder and lightning. This process is responsible for the thundersnow that occurs during blizzards and nor’easters, those powerful storms that regularly hit the eastern coast of the U.S. during the winter. Thundersnow can be pretty exciting—just ask The Weather Channel's Jim Cantore:

The name “thundersnow” can be a bit misleading. One of the most enjoyable things about a snowfall is how silent it is outside when there’s a thick blanket of snow on the ground. Snow absorbs sound waves so efficiently that you can usually only hear ambient noises immediately around where you’re standing. Snow muffles the sound of thunder for the same reason. Thunder that might be audible for many miles during a rainy thunderstorm might only be audible for a few thousand feet away from where the lightning struck. Unless the lightning strikes very close to where you are, you might only see a bright flash during thundersnow without ever hearing the thunder.

While thundersnow is a fascinating phenomenon to encounter, it does involve lightning, after all, and it’s just as dangerous as any other lightning bolt you’d see in a rainy thunderstorm. If you’re ever lucky enough to experience thundersnow, the event is best enjoyed indoors and out of harm’s way.

This piece originally ran in 2017.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios