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.

7 Wintery Facts About Ice, Freezing Rain, and Sleet

Razvan Socol via Flickr | CC BY-SA 2.0
Razvan Socol via Flickr | CC BY-SA 2.0

Whether you’re trying to fly across the country or you just want to buy groceries, a winter storm can have a significant impact on your life. But how can you tell if the ice, sleet, or freezing rain will prompt a winter weather advisory or a snow day from work? Here are a few facts about winter storm weather to help you prepare.

1. Freezing rain and sleet are a winter storm's silent hazards.

Ice in the form of freezing rain and sleet is just as big of a threat as snow, and often result in a winter weather advisory being issued for the affected region. Ice is arguably more dangerous than the fluffy white stuff. Snow is generally manageable: You can shovel it and plow it, and while others are doing the work, you can enjoy a snow day with a cup of hot cocoa. You can’t do that with ice.

For the most part, frozen water becomes solidly affixed to any exposed and untreated surface. There comes a point when ice is entirely unmanageable. Even a giant vehicle with four-wheel drive is useless when it can’t grip the surface it’s sliding on. Ice—mostly from freezing rain—is not only dangerous because of the associated travel hazards, but also because of the damage it can cause.

2. A winter storm with Freezing rain is dangerous.

Freezing rain is rain that freezes when it comes in contact with an exposed surface like a tree or a sidewalk. A small amount of freezing rain can leave a thin glaze of ice on just about any surface, creating a situation where surfaces that look wet are really icy instead. A steadier freezing rain will allow a crust of solid ice to form on trees and power lines, weighing them down to the point of breaking. Extreme ice accretions—over an inch—can cause significant damage and disrupt life for weeks at a time.

3. Freezing rain is actually melted snowflakes.

Freezing rain forms when there’s an inversion layer present during a winter storm. An inversion layer occurs when a layer of warm air gets sandwiched between two colder air masses. Snowflakes fall through the warm layer and completely melt before reentering the subfreezing air near the surface. This newly formed raindrop can’t freeze back into ice because it doesn’t have a nucleus around which to freeze, so the raindrop becomes supercooled, meaning it remains in liquid state even as its temperature drops below freezing. Once the supercooled raindrop reaches the ground, the water instantly freezes into ice.

4. All that ice from freezing rain is extremely heavy.

If you’ve ever had to carry a case of bottled water up a flight of stairs, you know that even a little bit of water is extremely heavy. Imagine even more weight on a much more fragile surface, and that’s what you get during an ice storm. Damage to trees can begin with just a quarter-inch of ice, with more damage to bigger and sturdier trees as the crust of ice grows thicker. The Weather Channel points out that just a half-inch of ice accretion on a standard power line can add 500 pounds of extra weight to the line and the poles supporting it. Extreme ice storms can cause as much damage as an intense tornado, as even a couple of inches of ice adds enough weight to crumple the tall steel transmission towers that carry high-voltage power lines—and those take a while to repair.

5. Sleet is freezing rain's annoying cousin. 

A close relative to freezing rain is sleet. Sleet, also known as ice pellets, forms through the same process as freezing rain. Snowflakes destined to become sleet also fall through a warm layer of air, but one that isn’t deep enough to melt the snowflake completely. Once the partially melted snowflake enters subfreezing air, there are still a couple of ice crystals left in the raindrop that allow the raindrop to freeze into a little ball of ice before reaching the ground. The result is an ice pellet about the size of half a grain of rice that makes a distinctive tinking noise as it bounces off cars, vegetation, and roofs.

6. Sleet is like snow that freezes solid. 

Sleet looks like snow and it accumulates like snow. It’s easy to mistake sleet for snow if you’re not a hardcore weather geek, but with enough accumulation, even the casual observer will know something is different pretty quickly. Sleet has a nasty habit of freezing into solid ice within a few hours of falling, especially if the Sun comes out or if temperatures briefly rise above freezing once the precipitation stops. Once this hardening occurs, it can be next to impossible to remove it from sidewalks, driveways, and roads until there’s a major thaw. In the southeastern United States, sleet is particularly common (and problematic), since the region is prone to warm air intruding on its winter storms and many municipalities don’t have enough snow equipment to clear the roads before that sleet freezes solid.

7. When a winter storm warning is issued, join the grocery lines.

Everyone makes fun of the throngs of panicked shoppers before a snowstorm, but stocking up on groceries before a winter storm is a pretty good idea for even the biggest cynic. If freezing rain knocks out power for an extended period of time, stores and restaurants will be forced to close until power is restored and they get fresh shipments of food. If that happens, you’re pretty much on your own for food and drink until conditions improve. Before a storm arrives, make sure you get plenty of food and beverages that you don’t have to cook or keep fresh.

Lake Michigan Has Frozen Over, and It's an Incredible Sight

Scott Olson, Getty Images
Scott Olson, Getty Images

A polar vortex has brought deadly temperatures to the Midwest this week, and the weather is having a dramatic effect on one of the region's most famous features. As the Detroit Free Press reports, parts of Lake Michigan have frozen over, and the ice coverage continues to grow.

The Lake Michigan ice extent has increased rapidly throughout January, starting around 1 percent on the first of the month and expanding to close to 40 percent by the end of the month. Yesterday was the coldest January 30 in Chicago history, with temperatures at O'Hare Airport dropping to -23°F. Even though it's frozen, steam can be seen rising off Lake Michigan—something that happens when the air above the lake is significantly colder than the surface. You can watch a stream of this happening from a live cam below.

Lake Michigan's ice coverage is impressive, as these pictures show, but it's still far from breaking a record. Though Lake Michigan has never frozen over completely, it came close during the winter of 1993 to 1994 when ice reached 95 percent coverage.

Midwestern states like Wisconsin, Michigan, Illinois, and Indiana aren't the only places that have been hit hard by the cold this winter. At the United States/Canada border, Niagara Falls froze to a stop in some spots, a phenomenon that also produced some stunning photographs.


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[h/t Detroit Free Press]

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