John Harrington Jr., professor of geography, is a synoptic climatologist who examines the factors behind distinctive weather events. He credits the increased tornado production this year to jet stream patterns in the upper atmosphere. The patterns have created synoptic events such as the April tornado outbreak in Alabama and recent tornado in Joplin, Mo. While these events are not unprecedented, they are significant, he said.
"To put them in all in one year, that's what has people talking about this stuff," Harrington said. "The fact that this is happening all in one year and in a relatively short time frame is unusual."
Special circumstances are necessary for the creation of tornadoes in the Great Plains, Harrington said. A humid atmosphere with moisture from the Gulf of Mexico and the right jet stream pattern coupled with surface convergence help to spawn a thunderstorm. Uplift from the jet stream helps to create the towering clouds associated with severe thunderstorms. Add a wind pattern set up with air filtering into the storm from the south at low levels, from the southwest at mid-levels and the northwest at higher levels, rotation of the thunderstorm cloud begins and its possible for a tornado to form.
"Unfortunately in terms of death and destruction, we've had too many of those events this year," Harrington said.
Forecasting tornadoes far ahead of time differs from the more advanced hurricane and weather prediction methods. The National Weather Service's Climate Prediction Center does not predict tornadoes, rather it attempts to predict jet stream patterns a month or so in the future.
In the wintertime the jet stream tends to flow above the southern United States. It migrates northward by the summertime. The area receiving the most tornadoes tends to shift with jet stream location as well. Oklahoma usually has a higher frequency of tornadoes in April, while Kansas experiences most of its tornadoes in May, Harrington said.
Synoptic patterns are different in autumn as the jet stream migrates back south, with much drier air across much of the U.S. While this does not preclude fall tornadoes from occurring, they are rare events. Connecting the surface conditions with the jet stream flow pattern helps a weather forecaster understand the likelihood for severe storms.
"That's pretty important in terms of understanding the kind of environment that will produce the necessary thunderstorms that rotate," Harrington said.
Extreme examples of weather have not been isolated to tornadoes. Heat waves, blizzards and severe storms have been increasingly more frequent or more severe according to U.S. data, Harrington said. These changes can be attributed to changes in the climate system.
The increase in severe weather events is drawing attention, he said.
"We have these good historical precedents for specific synoptic events, but they're starting to come more frequently together. That's what is very interesting, is that this weather system seems to be getting more variable."
John Harrington Jr., 785-532-6727, firstname.lastname@example.org
John Harrington Jr. | Newswise Science News
New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg
Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences