Spring flooding? Not this year, US forecasters sayMarch 15, 2012 By SETH BORENSTEIN , AP Science Writer in Earth / Environment
At least it's a dry heat. The federal government's spring weather forecast offers no respite from warmer weather, but the country should get a break from the spring flooding that's hit the last four years.
The National Weather Service's outlook for spring, which arrived early with 577 warm temperature records broken Wednesday, predicts mostly warmer and drier-than-normal weather, except in the Northwest. The current summer-like weather - with some temperatures as much as 35 degrees above normal - is expected to stick around through next week.
All or parts of 36 states are forecast to be warmer than normal April through June, with only Alaska, Hawaii, Washington and Oregon and the tip of Idaho forecast to be cooler than normal. Every state east of the Mississippi River, except Wisconsin, and most of the Southwest should be warmer than normal this spring, the weather service predicts.
No place in the contiguous United States is forecast to be wetter than normal this spring. The seemingly snowless winter - the third least amount of snow in the US in 46 years - means there is less snow melting and flooding rivers. So only a small fraction of the country has an above normal risk for flooding and no areas have a high risk of flooding this spring. Only the Ohio Valley and parts of Louisiana have elevated flood risk.
That's quite a change from last year when record flooding struck major rivers, including the Mississippi.
"The United States is getting a much needed spring break" from flooding, said National Weather Service Deputy Director Laura Furgione. "Due to a lack of snow pack residents along the Red River of the north may finally enjoy spring without sandbagging." That hasn't happened since 2008.
This spring less than 5 percent of the continental United States has an above -normal risk of flooding, compared to nearly half the country last year at this time, according to the weather service.
Flooding is the biggest weather killer in the United States on average, she said. There still could be flash flooding from extreme rainfall, Furgione said.
Meteorologists say drought should continue across much of the West and South, but shouldn't be quite as extreme as last fall, forecasters said. The Southeast should brace for some restriction on water use and in some places those have already started. While more of the country has severe drought, only 7 percent of the nation has extreme or excessive drought conditions, which are even worse than severe, said senior meteorologist David Miskus of the Climate Prediction Center.
The same conditions that made the winter so snowless and mild are likely to keep spring warm and dry, said Ed O'Lenic, operations branch chief at the climate prediction center. That's heavily influenced by the Arctic Oscillation, a northern cousin to the more well-known El Nino weather phenomenon. The Arctic Oscillation has keep storms and cold bottled far up north, making it milder and drier in much of the country.
While meteorologists can't connect a single weather event - like the unusual heat outbreak going on in much of the country - these types of extreme will happen more often and become more likely as the world's climate changes from man-made global warming, said O'Lenic and climate scientists.
Spring has started so early that weather forecasters are working with the Centers for Disease Control and Prevention in Atlanta to see if there is a way to monitor diseases that come from pests that would arrive earlier and stay longer because of warmer weather.
National Weather Service: http://1.usa.gov/z9eLoa
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"Spring flooding? Not this year, US forecasters say" March 15, 2012 https://phys.org/news/2012-03-year.html