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.
Sunshine will slowly fade away early this week as clouds move in ahead of the next storm system.
Above-normal temperatures will again move into the Los Angeles area.
A chance of rain is expected on Monday as a Pacific storm moves through the Northwest United States.
Seasonable, dry weather will prevail across the Atlanta area through Friday.
Umbrellas and raincoats will be needed this week in the Seattle area.
Sunshine and dry conditions will be seen over the Dallas-Fort Worth area through the end of the week.
Pagwa, Ontario, Canada (1923)
Highest amount of snowfall in Ontario for a climatological day - 36.0".
South Coast...greater than 80-mph katabatic winds this afternoon. Prudhoe Bay (oil area) ... temp around 10 degrees, winds to 65 mph much of the day. Wind chill around 55 below zero.
Seattle, WA (1987)
69 degrees - record high for the date - the 29th record high of the year.