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.

Denver is About to Experience Summer and Winter Temperatures Within 24 Hours

iStock.com/mphotoi
iStock.com/mphotoi

In a story tailor-made for exhaustive Weather Channel coverage, Denver, Colorado is about to experience one of the more bizarre weather shifts in recent memory. After an expected Tuesday high of 80°F, residents can anticipate a dramatic shift down to 32°F by midday Wednesday, with an initial half-inch of snow accumulation increasing to up to 7 inches by Wednesday night.

Put another way: Citizens who need to make sure they hydrate in the warm temperatures Tuesday will have to bring out the parkas the following day.

The Denver Post reports that the warm air coming ahead of the cold can result in a clash of air masses, prompting areas of low pressure that can create forceful and damaging weather conditions. The storm could bring winds of up to 60 miles per hour and possibly even cause power outages. Snow accumulation should dissipate by the weekend, when temperatures are expected to climb back into the 60s.

The high temperature record for April 9 in Denver is 81°F, set in 1977.

[h/t The Denver Post]

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]

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