- The Washington Times - Friday, December 29, 2006

The Washington area will ring in the new year after one of the 10 warmest Decembers in more than 100 years.

“It has been warm. It has been above average, that’s for sure,” said Chuck Caracozza, a meteorologist with Accuweather.com.

The average temperature for December 2006, through the 28th, was 44.3 degrees, which is tied for ninth-highest going back to 1872, according to National Weather Service records at Ronald Reagan Washington National Airport.

The last December to hit the top 10 was in 2001, when the average temperature was 45.5 degrees, which is tied for second-highest with 1982 and 1971.

The normal average temperature is 39.5 degrees, said Steve Zubrick, science and operations manager at the National Weather Services’s Northern Virginia office.

Temperatures yesterday exceeded 50 degrees, with lows in the high 30s, and the same is forecast for today. Average temperature is calculated by adding a day’s high and low, then dividing the number in half.

So December 2006 could end up as the seventh- or eighth-warmest December since 1872, but will not likely crack the top six, Mr. Zubrick said.

“More than likely, it’s probably going to edge up,” he said.

However, D.C. residents may still see freezing weather and snow this winter.

“My gut feeling is that sometime in January we’re probably going to dive down into the ice box and have a period of cold weather, with precipitation probably in the frozen form,” Mr. Zubrick said. “And then it will moderate quickly and maybe February will be normal. And then you’re staring at March and people will say, ‘Where did winter go? We didn’t have a winter.’ ”

Two years are tied for having the warmest Decembers in recorded history. In 1889 and 1984, the average December temperature was 45.6 degrees.

There is no significant trend of warm winters over the past six years. December was 3.1 degrees colder than usual last year, and has fluctuated up and down since 2000.

“I don’t really see a trend,” Mr. Zubrick said.

But seven of the top 10 warmest Decembers have occurred since 1971. In addition, the weather phenomenon called El Nino, which is an indicator for a warmer-than-normal winter, has occurred much more frequently in the past 20 years.

The El Nino condition, also known as a Pacific warm episode, simply means the Pacific Ocean is warmer than usual. The Pacific is now in the midst of one of the cycles.

“Just looking back over the last 50 years or so, when we’ve had El Nino conditions in the Pacific, our December months in the Mid-Atlantic region have tended to trend above normal,” Mr. Zubrick said.

El Nino conditions came along once a decade from the 1950s through the 1970s, occurring in the winters of 1957-1958, 1965-1966, and 1972-1973, Mr. Zubrick said.

But since the 1980s, they have come with more frequency, occurring in the winters of 1982-1983, 1986-1987, 1987-1988, 1991-1992, 1994-1995, 1997-1998, and 2002-2003.

“It’s almost like we’ve been getting more El Ninos,” Mr. Zubrick said.

Warming temperatures over the past several years have encouraged plant growth in the area among types that previously could not survive colder winters, according to the National Arbor Day Foundation.

But some plant specialists say the U.S. National Arboretum has simply developed more cold-hardy varieties of plants that are normally found farther south.

The foundation surveyed the country’s average low temperatures and found them to be higher than they were in 1990.

Foundation officials attributed these increases to global warming and encouraged residents to plant more trees to counteract global warming. More trees will lessen the effect of air pollution on the atmosphere, they said.

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