Studying newly discovered air patterns has helped meteorologists find a way to forecast killer heat waves in the U.S. more than three weeks in advance.
Extreme heat is responsible for 600 to 1,300 deaths in the United States each year. Tellingly mortality rate from heat waves is higher than that occurring from all other natural disasters combined. If meteorologists predict such heat waves well in advance, people can be more prepared and a lot of lives can be saved. In the new study, meteorologists from the National Center for Atmospheric Research in Boulder may have found a way to do just that.
The solution to earlier forecasting of heat waves was found after scientists studied a strange air pattern, which they termed as "wavenumber 5." It consists of five sequences of alternating high and low pressure systems evenly distributed across the Northern Hemisphere. Such patterns are a precursor of prolonged and intense heat waves in the eastern two-thirds of the United States.
For the study, scientists looked at heat waves that lasted at least a week and were about 5 to 8 degrees warmer than normal. In any given summer week, the odds of a heat wave like this happening are usually only about 1 in 67 in the United States. After conducting thousands of computer simulations, they found that most heat waves in the country succeeded such air patterns up to 15 to 20 days after they were detected.
"This concept could lead to better forecasting of heat- wave events, allowing society to better prepare for these types of phenomena," said Jeff Weber, a researcher at the University Corporation for Atmospheric Research in Boulder, according to LiveScience.
Haiyan Teng, a scientist at the National Center for Atmospheric Research in Boulder confirmed that these air patterns are not caused by any specific oceanic pattern or heating of Earth's surface. It is a naturally occurring atmospheric condition. Earlier researchers were able to predict only a week or 10 days in advance such heat waves by studying the periodic warming and cooling of surface waters in the Pacific .
"Every climate model has biases, but we think this pattern is not just a pattern that exists in the model," NBC News quoted Teng as saying. "It has been noticed in nature by other studies."
The forecasts can be made irrespective of the weather on the ground at the time of the pattern. The same pattern that signals a U.S. heat wave also indicates different extreme weather in other parts of the globe, like heavy rains.
This wave pattern was seen before the 1980 heat wave that was blamed for 1,250 deaths and pushed temperatures over 100 degrees in Dallas every day, said Randall Dole, a senior scientist at the National Oceanic and Atmospheric Administration. Triple-digit temperatures in Dallas persisted for a record 42 consecutive days that year. Dole, who wasn't part of the study, said the science behind the study is sound, significant and may be practical after extensive testing.
