Northern states might actually profit as the planet warms. This article will probably make you wish that you lived in Seattle. Pexels Union County, Florida is 250 square miles, nestled in the middle of the state’s pan—not the handle—about an hour southwest of Jacksonville and nearly as far from the state’s southern border. Residents depend on… Continue Reading →
Nikki Haley refused to agree with CNN’s Jake Tapper when he asked her about Trump’s view on global warming, “You’re not willing to acknowledge that calling climate change a Chinese hoax is just a big box of crazy” and “it’s nonsense?” Instead, the UN ambassador tried to hoodwink Americans by switching the topic to the Paris… Continue Reading →
Syria and Nicaragua is proud to accept the United States into their league of third-world nations for whom climate change is neither a priority nor a concern. Meanwhile, the President of the United States has now informed the world that he is willing to cede leadership on climate change to China, preferring to bow before the… Continue Reading →
Editor’s note: May and June are typically peak months for tornadoes in North America. We asked Penn State meteorology professors Paul Markowski and Yvette Richardson to explain why tornadoes form, how to stay safe if you’re near one and whether climate change is affecting tornado patterns.
1. Where are tornadoes most likely to occur?
Most headline-making tornadoes are spawned by what are known as supercell thunderstorms. These are large, intense storms characterized by an updraft (rising air) that rotates.
Thunderstorms develop when warm, humid air near the surface lies beneath a thick layer of air in which the temperature decreases rapidly with height. We call this type of atmosphere “unstable,” meaning that when air is nudged upward, the water vapor that it contains condenses. This releases heat, making the air warmer than its surroundings. The air becomes buoyant and rises, creating the towering clouds we associate with thunderstorms.
The second key condition for supercell formation is wind shear – large changes in wind at different levels. Winds at different altitudes blowing at different speeds and/or from different directions is associated with horizontally spinning air, like a rolling pin. As this horizontally spinning air flows into the updraft, the spin is tilted into the vertical, creating a rotating updraft.
Tornadoes are especially likely to be spawned by supercell thunderstorms when the lowest altitudes are particularly humid and possess exceptionally strong wind shear. These conditions are more likely to come together in certain locations, such as the U.S. Great Plains and Southeast.
2. How do actual tornadoes form?
Not all supercell thunderstorms produce tornadoes. Once wind shear has created a rotating updraft in our supercell thunderstorm, other processes develop rotation near the ground, in the cool air underneath the storm, which we call its “cold pool.” The cold pool is produced mostly by the evaporation of rain.
Within and beneath the storm, warm air is rising and cooler air is descending. As air descends and flows through the cold pool, the horizontal differences in temperature and acceleration of air along the ground combine to produce more horizontal spin. If there is strong upward suction from the overlying rotating updraft of the supercell storm, and the air in the cold pool is not too cold, the horizontally spinning air can be tipped toward the vertical and sucked upward. It also can be contracted inward and spin faster, just as skaters increase the speed of their spins by pulling in their arms. This forms the tornado.
3. How precisely can we predict tornado strikes?
In the past decade, forecasters have become skillful at identifying conditions that can support strong tornadoes – those rated EF2 or higher on the Enhanced Fujita Scale. The National Weather Service’s Storm Prediction Center routinely predicts large outbreaks days in advance. “High-risk” outlooks capture most major tornado events, and strong tornadoes rarely occur outside of tornado watches. We have less ability to forecast tornadoes in more marginal situations, such as within non-supercell storms.
Even if the environment is extremely favorable for supercell tornadoes, forecasters have limited ability to say when or if a specific storm will produce a tornado. Researchers are studying triggers for tornado production, such as small-scale downdraft surges and descending precipitation shafts on a supercell storm’s rear flank, and processes that sustain tornadoes once they form.
We don’t understand tornado maintenance well, or how tornadoes might be affected by interactions with obstacles such as terrain and buildings. This means that when a tornado is occurring, forecasters have limited ability to tell the public how long they expect it to last.
4. What should I do during a tornado warning?
Basements, storm cellars or “safe rooms” that meet federal guidelines provide excellent protection. If none of these is available, the best strategy is to go to the lowest floor of a sturdy building and put as many walls between you and the tornado as possible. In other words, shelter in an interior room, such as a closet or bathroom. Also, make sure you are wearing good shoes. If your area takes a direct hit, you do not want to walk through a debris field barefoot.
Don’t chase tornadoes without professional training. Observations from spotters are valuable to forecasters who are issuing warnings, but they can be made from a distance. We don’t need people driving in harm’s way to know that a dangerous storm is approaching.
5. Is climate change making tornadoes bigger or more frequent?
It’s hard to say. Reliable U.S. records of tornadoes go back only to roughly 1950, and records outside of the United States are even less complete. Thanks to storm chasing and the spread of camera phones, more tornadoes are counted today compared with yesteryear, but that does not necessarily mean that more are occurring. And there’s a lot of natural variability from year to year. Over the past decade, the annual U.S. tornado count has ranged from 886 to 1,690 storms per year.
Estimates of wind speeds based on post-storm damage surveys can be off by 50 percent or more. And many tornadoes in remote areas leave no clues as to how strong their winds were.
Most climate models predict that there will be more days per year when the atmosphere would have sufficient instability and wind shear to support tornadoes. But we need to be careful in interpreting this result. Climate models don’t capture tornadoes, their parent thunderstorms or nuances in the lowest level of the atmosphere that affect tornado formation. So it is hard to say whether there will be more tornadoes, even if tornado-supporting environments become more common.
The Senate failed Wednesday to overturn an Obama-era methane restriction, unable to muster a simple majority to repeal the rule when three Republicans who were expected to vote yes instead voted no on the repeal. Sens. John McCain, R-Ariz., Susan Collins, R-Maine, and Lindsey Graham, R-S.C., voted no on the motion to proceed in repealing the… Continue Reading →
Lawmakers are questioning the motives behind the Department of Energy’s decision to study whether government support for renewable energy resources are threatening the reliability of the nation’s power grid and contributing to the closure of coal-fired and nuclear power plants.
In a letter sent to Energy Secretary Rick Perry on Monday, several Democratic senators called the request for the grid reliability study “a thinly disguised attempt to promote less economic electric generation technologies, such as coal and nuclear, at the expense of cost-competitive wind and solar power.”
The study appears intended to blame wind and solar power for the financial difficulties facing coal and nuclear generators and suggest that renewable energy resources threaten the reliability of the grid, the senators said.
In a memo to his chief of staff last month, Perry requested DOE investigate how federal subsidies boost one form of energy at the expense of baseload generation. The memo specifically directed the agency to look at the extent to which “continued regulatory burdens, as well as mandates and tax and subsidy policies, are responsible for forcing the premature retirement of baseload power plants.”
Yeah, the wind and the sun are the wild cards. Uh huh.
The Antarctic Ice Sheet is draining huge quantities of water out to sea. When climate scientists look at Antarctica, they see a ticking time bomb. If the ice sheet melts, it will raise sea levels by tens of feet, flooding coastal cities around the globe. For now, the southern continent is relatively stable, but it’s starting… Continue Reading →
It’s one souvenir you really don’t want to bring home CDC Angiostrongylus cantonensis larva You may have read a thing or two lately about the oh-so-grossly-named rat lungworm. This brain parasite isn’t new, but only became routine in the United States in recent years. Angiostrongylus cantonensis favors tropical climes, and used to crop up only in… Continue Reading →
Coal mining is not coming back. Even coal companies admit that. The role of coal in energy production has largely been superseded by natural gas, and continues to diminish over time. Many Trump voters in West Virginia and surrounds know this, but they still cling to their hopes that jobs will once again flow free in… Continue Reading →
It was 66 degrees yesterday — people were outside in shorts. Today, we’re expected to get 8″ of snow. The schools are closed.
As is the tradition here, here’s Trip Shakespeare: