The Midwest and northern states will likely get a warmer winter, while the Southeast should expect the opposite, cooler and wetter, according to federal weather forecasters.
In its outlook for December through February, the federal Climate Prediction Center said Thursday that the current El Nino weather event will affect America's winter temperatures.
"We expect El Nino to strengthen and persist through the winter months, providing clues as to what the weather will be like during the period," Mike Halpert, the center's deputy director, said in a statement. "Warmer ocean water in the equatorial Pacific shifts the patterns of tropical rainfall that in turn change the strength and position of the jetstream and storms over the Pacific Ocean and the U.S."
In particular, the center listed these probable winter "highlights":
- Warmer-than-average areas: "much of the western and central U.S., especially in the north-central states from Montana to Wisconsin. Though temperatures may average warmer than usual, periodic outbreaks of cold air are still possible."
- Colder-than-average areas: "across the Southeast and mid-Atlantic from southern and eastern Texas to southern Pennsylvania and south through Florida."
- Above-average rain areas: "expected in the southern border states, especially Texas and Florida. Recent rainfall and the prospects of more should improve current drought conditions in central and southern Texas. However, tornado records suggest that there will also be an increased chance of organized tornado activity for the Gulf Coast region this winter."
- Below-average rain areas: "expected in the Pacific Northwest and the Ohio and Tennessee River Valleys."
The Northeast, for its part, has "equal chances for above-, near-, or below-normal temperatures and precipitation," the center said. "Winter weather in this region is often driven not by El Nino but by weather patterns over the northern Atlantic Ocean and Arctic, such as the North Atlantic Oscillation. These patterns are often more short-term, and are generally predictable only a week or so in advance."
California was said to have a "slight tilt in the odds toward wetter-than-average conditions."
Alaska should see "milder-than-average temperatures except along the western coast" and "equal chances for above-, near-, or below-median precipitation for most areas except above median for the northwest."
Hawaii is expected to see "below-average temperatures and precipitation."
And it may not be good news for next year's Olympics in Vancouver, Canada.
The Olympic city can expect "a dry and warm winter but it certainly can be cool enough for snow," Halpert said.
Overall, slightly more than half the nation by area will be warmer than normal, Halpert said, but when it comes to where most people live, about half the population is likely to have warmer weather and the other half cooler.
Halpert added that "other climate factors are also likely to play a role in the winter weather at times across the country. Some of these factors, such as the North Atlantic Oscillation, are difficult to predict more than one to two weeks in advance. The NAO adds uncertainty to the forecast in the Northeast and Mid-Atlantic portions of the country."
September was warmer than normal for the United States, but not greatly hotter than normal, ranking 32nd out of 115 Septembers on record. But Nevada had its warmest September on record and California tied for its warmest month on record. The nation's rainfall in September was exactly average.