The western half of the continental U.S. and central and northern Alaska could be in for a warmer-than-average winter, while most of Florida might be colder-than-normal December through February, according to NOAA's annual Winter Outlook.
Forecasters with NOAA's Climate Prediction Center say a wavering El Niño, expected to have developed by now, makes this year's winter outlook less certain than previous years.
"This is one of the most challenging outlooks we've produced in recent years because El Niño decided not to show up as expected," said Mike Halpert, deputy director of NOAA's Climate Prediction Center. "In fact, it stalled out last month, leaving neutral conditions in place in the tropical Pacific."
When El Niño is present, warmer ocean water in the equatorial Pacific shifts the patterns of tropical rainfall that in turn influence the strength and position of the jetstream and storms over the Pacific Ocean and United States. This climate pattern gives seasonal forecasters confidence in how the U.S. winter will unfold. An El Niño watch remains in effect because there's still a window for it to emerge.
Other climate factors can influence winter weather across the country. Some of these factors, such as the North Atlantic Oscillation, a prominent climate pattern, are difficult to predict more than one to two weeks in advance. The NAO adds uncertainty to the winter outlook in the Northeast and Mid-Atlantic portions of the country.
Areas ravaged by extreme drought over the past year are unlikely to see much relief from drought conditions this winter.
In the 2012 U.S. Winter Outlook (December through February) odds favor:
-Warmer-than-average temperatures in much of Texas, northward through the Central and Northern Plains and westward across the Southwest, the Northern Rockies, and eastern Washington, Oregon and California, as well as the northern two-thirds of Alaska.
-Cooler-than-average temperatures in Hawaii and in most of Florida, excluding the panhandle.
-Dryer-than-average conditions in Hawaii, the Pacific Northwest and Northern California, including Idaho, western Montana, and portions of Wyoming, Utah and most of Nevada.
-Dryer-than-average conditions in the upper Midwest, including Minnesota, Wisconsin, Iowa and northern Missouri and eastern parts of North and South Dakota, Nebraska, Kansas, and western Illinois.
-Wetter-than-average conditions across the Gulf Coast states from the northern half of Florida to eastern Texas.
The rest of the country falls into the "equal chance" category, meaning these areas have an equal chance for above-, near-, or below-normal temperatures and/or precipitation.
This seasonal outlook does not project where and when snowstorms may hit or provide total seasonal snowfall accumulations. Snow forecasts are dependent upon the strength and track of winter storms, which are generally not predictable more than a week in advance.
Earlier this week, a strengthening nor'easter battered New England, causing widespread damage across the region while storms continued to drench and blast the coastal Northwest.
A siege of Pacific storms will continue to drench and blast the coastal Northwest into next week and will be joined by Ana.
After many locations over the Plains feel like late summer this weekend, the record-challenging warmth will expand to the Northeast next week.
The disturbance responsible for drenching South Florida downpours will swing toward Bermuda this weekend, while the former Tropical Depression 9 lurks in the northwestern Caribbean Sea.
Much calmer conditions expected Saturday across the Northeast as this week's nor'easter shifts away from the region.
The NFL returns to London this weekend amid a mild stretch of weather.
Tampa, FL (1921)
Hurricane "most destructive/highest tide," pressure 28.81"/975.6 mb, winds 100 mph, tide 10.5 feet, six dead and $3 million damage.
Strong coastal storm with winds exceeding 100 mph over the ocean; 82-mph wind gust at south end of Chesapeake Bay Bridge Tunnel. Bethany Beach Delaware being evacuated as waves came over the dunes. Heavy snow in NC mountains. Mt. Pisgah - 11 inches; Mt. Mitchell - 6 inches.
Caribou, ME (1990)
19 consecutive days of measurable precipitation.