An extended winter weather forecast, released Tuesday by Chief Long-Range Forecaster Joe Bastardi and his team, calls for a cooler than normal beginning and end to this winter, wrapped around three months of higher temperatures that could make it a warmer season than last year and one of the 10 warmest winters ever for the southeastern United States.

The AccuWeather forecast for the months of November through March calls for a warmer winter than last year for the nation as a whole, especially in the second half of January and February, when last winter saw its coldest temperatures. While November and March may be colder than normal, temperatures between December and February could make the winter of 2007-2008 as warm as the 1998-1999 and 2001-2002 winters, according to the AccuWeather team. Warm weather will be centered over the Tennessee Valley and the Carolinas. More than 75% of the days this winter could see temperatures above normal in most of the nation southeast of a line from the Great Lakes to the Southwest, Bastardi said. Only the Pacific Northwest is expected to see temperatures below normal.

Bastardi’s winter forecast was generally in agreement with recent predictions from the National Oceanographic and Atmospheric Administration (NOAA) and others calling for a relatively warm winter (see Daily GPI, Oct. 19). NOAA recently said its latest model runs confirm its earlier prediction for above-average temperatures over most of the country and a continuation of drier-than-average conditions across much of the Southwest and Southeast.

For the country as a whole, NOAA’s updated heating degree day forecast for December through February projected a 3.4% warmer winter than the 30-year normal but a 0.7% cooler winter than last year. The entire eastern and central United States is expected to record warmer than normal conditions with the south central region recording the warmest temperatures over normal, NOAA said. Andover, MA-based WSI Corp. said temperatures will average warmer than normal November to January in all locations except for parts of the northern Rockies, northern Plains and extreme northern New England (see Daily GPI, Oct. 23).

“The effect across the United States may be that we have the colder parts of the cold season, relative to normal, early and late,” Bastardi said. “It may feel shockingly cold compared to the record-setting warmth of October and the warmth of the winter, but not extreme compared to normals of the time of the year — in other words, colder than normal but not extreme. The warmth coming at the traditionally coldest time of the winter will be very unusual.”

According to AccuWeather, colder water developing in the northern Pacific with the warmer water between it and the cold la Nina current could produce a stronger-than-normal “fire-hose” jet into the Pacific Northwest that would then lift through southern Canada and into the North Atlantic with a stronger than normal positive arctic oscillation for the winter season. The effect will be masked in November and again in early spring.

The continuing La Nina event and trends drawn from models in the southern hemisphere, European seasonal models and the U.S. Climate Forecasting System all point to the same conclusion, Bastardi said.

“For the core of the winter, this one looks like the warmest of the last three for much of the nation. Once it gets warm, it may stay warm all winter and not reverse like last year, or it will be cold the first and last three weeks of the winter like 2005-2006,” he said.

“The characteristic of this winter appears to be that in most areas from the Plains east, even when it gets cold, the warmth will be seen coming back in a short period of time. In other words, sustainable week-after-week cold like last year is not likely. More likely are mid-winter intrusions that hit and run, and rarely, if at all, visit the Southeast.”

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