Winter forecast cold north, dry south, heavy snowOctober 20, 2011 By RANDOLPH E. SCHMID , AP Science Writer in Earth / Earth Sciences
(AP) -- Winter looks to be cold and wet across the northern tier of states, and the drought will worsen in the South, where conditions are expected to be warmer and drier than usual, government forecasters said Thursday.
Like last winter, the Pacific Ocean cooling known as La Nina is affecting the weather, according to the National Oceanic and Atmospheric Administration.
Mike Halpert, deputy director of the agency's Climate Prediction Center, said snowfall probably will top the usual amounts from the Northwest to the Great Lakes and the Ohio and Tennessee river valleys.
Dry conditions could extend from Southern California east across drought-stricken Texas and Oklahoma and along the Gulf Coast into Florida and possibly north to Virginia.
Winter weather in other areas and the Northeast could go either way, the researchers said.
While the forecast is not guaranteed, it could be more bad news for drought-stricken regions.
Already 91 percent of Texas, 87 percent of Oklahoma and 63 percent of New Mexico are in extreme or exceptional drought, said David Brown, director of Southern Regional Climate Services for NOAA. The unusually dry conditions also extend into Arizona, Colorado, Kansas, Arkansas and Louisiana, he noted.
Continued dry conditions will affect farming, livestock and other pursuits.
It would take 10 inches to 15 inches of rain in some areas to make an appreciable difference, Brown said, and "the likelihood of seeing that kind of relief is pretty low."
At the same time the forecast for December, January and February looks to be cool along with West Coast and across the northern states to the Great Lakes. Wetter than normal conditions cover that area and extend a bit farther east and south, possibly as far as western New York and south to Kentucky.
Some of the details by region:
-Pacific Northwest: Colder and wetter than average; increased mountain snow in the Pacific Northwest and western Montana. There could be spring flooding in the Missouri River Basin.
-California: Colder than average with odds favoring wetter than average conditions in northern California and drier in southern California.
-Northern Plains: Colder and wetter than average; spring flooding could be a concern.
-Southern Plains and Gulf Coast states: Warmer and drier than average; will probably worsen drought conditions.
-Florida and south Atlantic Coast: Drier than average, with an equal chance for temperatures above, near or below normal; worse than normal wildfire conditions.
-Ohio and Tennessee Valleys: Wetter than average with equal chances for temperatures above, near or below average; potential for increased storminess and flooding.
-Northeast and Mid-Atlantic: Equal chances for temperatures and precipitation above, near or below normal. Winter weather in these areas is often driven by a pressure change called the Arctic Oscillation, which is difficult to forecast. If enough cold air and moisture are in place, areas north of the Ohio Valley and into the Northeast could see above-average snow.
-Great Lakes: A tilt toward colder and wetter than average.
-Hawaii: Above-average temperatures are favored in the western islands. Statewide, the current drought is expected to continue through the winter, though recovery is more likely over the windward slopes of the Big Island and Maui.
-Alaska: colder than average over the southern half of the state and the Panhandle with below average precipitation in the interior eastern part of the state.
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"Winter forecast cold north, dry south, heavy snow" October 20, 2011 http://phys.org/news/2011-10-winter-cold-north-south-heavy.html