Scientists have identified a pattern in the atmosphere that may eventually allow the forecasts of heat waves from about 15 to 20 days in advance.
The study, published this week in Nature Geoscience, looked for patterns after building a 12,000-year simulation of the atmosphere over the Northern Hemisphere. Lead scientist Haiyan Teng called the discovery a “tiny, baby step forward” in predicting one of weather’s more deadly events.
Teng is a researcher at the National Center for Atmospheric Research in Boulder, Colo. The study was funded in part by the U.S. Department of Energy, the National Science Foundation and NASA.
Typically, meteorologists don’t have a lot of confidence in their computer models beyond five to seven days, Teng said.
She and fellow researchers Grant Branstator, Hailan Wang, Gerald A. Meehl, and Warren Washington identified a pattern of five ridges and troughs, called wavenumber-5, that tended to precede heat waves by about 15 days.
The pattern wasn’t tied to oceanic conditions or surface heating of the Earth but was associated with atmospheric phenomenon, Teng said. When a wavenumber-5 pattern occurred in the atmosphere, a heat wave was more likely to form over the U.S. about 15 days later. When the patterns were amplified, a heat wave’s probability more than quadrupled than what would be expected by chance, Teng said.
It will take more research to know, for example, whether computer models will help scientists say with some confidence where in the U.S. a heat wave might occur, Teng said.
“There are still so many things we don’t understand,” Teng said. “We’re trying to improve the probability.”
Heat waves are among the most deadly weather events. A study of mortality rates in 100 U.S. cities last year found that the risk of death increased 2.49 percent for every 1 degree Fahrenheit increase in the temperature and another 0.38 percent for each additional day in a heat wave.
Heat waves also are occurring more frequently. Research from the University of Alabama published earlier this year found that the Southeast and Great Plains have seen more days of heat waves and more widespread heat waves in recent years, and more than any other region of the country from 1979 to 2011.
Michael Penaluna, Denton’s emergency manager, finds advance notice of big weather helpful. That even includes the seasonal forecasts for hurricanes that give probabilities for named storms and possible landfalls, he said.
If one day meteorologists are able to predict heat waves, including temperature and drought conditions, the community response could matter, he said.
“We could get a head start on water conservation efforts and do more for wildfire preparedness with clearing brush and building fire breaks,” Penaluna said.
“In future years, I think water conservation efforts are really going to matter,” Penaluna said. “It’s always beneficial to have information.”
PEGGY HEINKEL-WOLFE can be reached at 940-566-6881 and via Twitter at @phwolfeDRC.