Does the Thunderstorm "Bubble" Really Exist?

Have you ever watched a promising thunderstorm barrel toward you, only to see it fall apart or shift course at the last second? It can be frustrating to expect the cooling relief of a nice deluge—only to be left high and dry as you watch the dark clouds fade away on the horizon.

It’s common to describe this phenomenon as a “bubble,” a perceived forcefield hovering over your town that seems to deflect storms when you want them the most. There’s even an XKCD comic about it. Of course, those mythical deflectors don’t exist, but why do storms seem to consistently hit certain areas, while often skipping nearby towns?

Some local features, like large, cool bodies of water or tall mountains, really can affect how thunderstorms behave. But for the most part, a storm suddenly missing one location is mostly the result of how these bubbling masses of air and moisture evolve throughout their short lifecycle.

There are three common types of thunderstorms—single-cell, multicell (think squall lines), and supercells. The latter two categories are commonly associated with organized severe weather outbreaks. By far the most common type of thunderstorm around the world is a single-cell. This is a small, localized burst of convection often called a pop-up, popcorn, or garden-variety thunderstorm.

If there isn’t a focus point for thunderstorms to develop—something like a cold front or a sea breeze—the exact location where one of these warm weather torrents develops is usually pretty random. A storm will pop up, produce lots of lightning and heavy rain for a little while, and then start to dissipate. The cold air rushing away from the decaying storm will serve as a focus for more thunderstorms to develop nearby. Whether or not you get hit by an approaching thunderstorm depends on how healthy it is, and if any other storms form in its wake. In other words, if a storm falls apart a block away from you, it’s usually a stroke of atmospheric luck.

If you average out precipitation trends over a long period of time, the data show that rainfall is pretty evenly distributed between neighboring communities. One storm could miss you and hit the town next door, while the storm that hits you missed your neighbors down the street. It balances out with time.

However, there are some cases where certain towns benefit from their surroundings when a thunderstorm is on its way. Thunderstorms can start to weaken as they approach more stable air near cool bodies of water like the Atlantic Ocean or the Great Lakes. There is also some truth that mountains are less conducive to storms, as the rough terrain and cooler temperatures can disrupt the updraft and temporarily weaken storms as they traverse the terrain. That certainly isn’t always the case, though—there are plenty of rocking storms along the coast and in the mountains every season.

So for the most part, if a thunderstorm looks like it’s coming straight for you and then disappears into thin air, it has less to do with where you live and more to do with the fragile, fluid structure of these magnificent natural formations.

Amazing Timelapse Shows Florida Sky Turning Purple Following Hurricane Dorian

Scott Olson/Getty Images
Scott Olson/Getty Images

Photographs taken of Hurricane Dorian's massive eye and the damage it caused in the Bahamas paint a picture of what it was like to live through the historic storm. But some of the most stunning images to come out of the event were captured after the hurricane had passed. As KENS5 reports, the time-lapse video below shows the sky over Florida turning a unique shade of purple in the wake of Hurricane Dorian.

Dorian skimmed the east side of Florida earlier this week, causing power outages and some flooding. The worst of the storm was over by Wednesday night, but the ominous purple clouds it left behind may have sparked concern among some Florida residents.

A purple sky following a hurricane is the result of a perfectly natural occurrence called scattering. The sky was super-saturated after Dorian arrived, and the moisture in the atmosphere refracted the light of the setting sun. Normally, only the longest wavelengths of light on the color spectrum are visible through the clouds—that's why sunsets often appear gold, pink, and orange.

Violet is the shortest wavelength on the spectrum, which means it's almost never visible in the sky. But the air's high dew point Wednesday night, combined with the dense low-hanging clouds, created the perfect conditions for a rare purple sky.

Locals who've lived through a few hurricanes may have recognized the phenomenon; the same thing happened after Hurricane Michael hit Florida last year.

[h/t KENS5]

See What the Eye of Hurricane Dorian Looks Like From Space

NOAA, Getty Images
NOAA, Getty Images

Hurricane Dorian has already caused damage on the ground, leveling houses and killing at least five people in the Bahamas earlier this week. For people who haven't seen Dorian's power up close, these pictures captured from space put the magnitude of the storm into perspective.

As Live Science reports, the photographs below were taken by European Space Agency astronaut Luca Parmitano aboard the International Space Station. They show the hurricane swirling over the Atlantic, its massive eye in clear view.

The storm has grown even more intense since it was photographed from space. According to a tweet from Parmitano on September 1, the pictures show Dorian as a tropical storm. By the time the system reached the Bahamas on Monday, September 2, it had upgraded to Category 5 hurricane with winds exceeding 185 mph. Dorian has since weakened to a Category 3, but that's still strong enough to cause significant destruction if it makes landfall over the U.S.

After preparing for a direct hit all week, it looks as though the southern U.S. may be spared from the worst of the storm. Projections now show Dorian hugging the Atlantic coast, starting off the coast of Florida and skimming Georgia, South Carolina, and North Carolina. The hurricane is still likely to drive powerful winds and storm surges along the east coast, so local governments are urging residents to take any necessary precautions and be prepared to evacuate if the order is given.

[h/t Live Science]

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