The collision between updraft and jet stream also causes a ripple effect and transports cirrus cloud ice downstream to form the plume. "So jet-stream winds are forced to go around."Īs the jet-stream air collides with the updraft, it rises slightly and becomes colder, forming a U- or V-shaped area of cold temperatures. "You have wind flows exceeding 100 miles an hour at the jet-stream level running into this towering updraft," said Bedka. There, racing stratospheric jet-stream winds and powerful updrafts collide. Plumes form when intense updrafts puncture the tropopause and drag cloud tops up into the stratosphere with them. As storm-producing cumulonimbus clouds hit the tropopause their tops flatten out, giving them an anvil-like appearance. Typical thunderstorms top out at the tropopause, the boundary between the troposphere - the lowest part of Earth's atmosphere - and the stratosphere. To understand why the plumes are such good indicators of severe weather, it helps to understand the conditions that generate them. "Water vapor is a powerful greenhouse gas, and its presence in the stratosphere has strong impacts on climate.” “Plume signatures are not only useful for identifying potentially severe storms, but they also represent transport of ice and water vapor into the stratosphere," said Elisa Murillo, a graduate student at the University of Oklahoma who has collaborated extensively with Bedka on AACP research. In addition, their findings could help weather forecasters provide earlier warnings of severe and tornadic storms not just in the U.S. Their research is showing that compared to non-plumed storms, plumed storms are significantly more likely to produce high winds, major tornadoes and large hail. this summer as outbreaks of severe weather have raked across the Midwest, bringing high winds, tornadoes and hail with them.īedka is studying the AACP phenomenon with colleagues at the University of Oklahoma. The plumes have been a frequent sight over the U.S. "The plume pattern in the imagery instantly tells you without the need for radar or lightning observations or other information that these are the storms you really, really need to look out for," said Kris Bedka, an atmospheric scientist at NASA's Langley Research Center in Hampton, Virginia. It's not quite a smoking gun, but one could be forgiven for thinking of it that way: a distinctive cloud formation that often signals damaging storms below.Įasily identifiable in satellite imagery, the Above Anvil Cirrus Plume, or AACP, looks like a plume of smoke emanating out from the top of what, in all likelihood, is a serious storm.
0 Comments
Leave a Reply. |