Most meteorologists define winter as the onset of winter-like conditions. This occurs in the Northeast around the beginning of December, although winter scientifically starts on Dec. 22, when the noontime sun is farthest south in the northern hemisphere. This is called the Winter Solstice.

With every change of the season NOAA Climate Prediction Center publishes a weather outlook. This information is based on the calculated norms for the past thirty years of recorded observations. According to this year’s winter weather outlook for December to February 2006/2007, the Northeast is in for a mild winter.

The Northeast, Northern Mid-Atlantic, Midwest, Northern Plains, and Central Plains will experience a warmer than normal winter. Now this does not mean temperatures in the 60’s every other day but it does mean that the number of Artic blast conditions will be fewer in number.

In terms of precipitation, NOAA is calling for equal chances of higher or below normal precipitation amounts for the east coast, but the entire southern part of the United States is predicted to have a wetter than normal winter.

So what causes a warmer, cooler, wetter, and/or drier winter? Many have heard of El Nino Southern Oscillation, or ENSO. These terms describe warmer than normal conditions in sea surface temperatures off the Pacific Coast of South America. This oscillation creates a shift in the Jet Stream over the United States.

The Jet Stream is a fast moving river of air high above the surface that acts like a conveyor belt for the storms that move across our nation. When El Nino is present, this Jet Stream is shifted, and the storm tracks concentrate in different positions.

With the presence of a strong El Nino pattern, the storm track of the Jet Steam is predicted to move off the Northeast, bringing a mild winter. Because other factors affect the position of the Jet Stream there can be small uncertainty in season prediction, but NOAA can be confident in forecasting fewer bitter cold outbreaks for the Northeast this winter.

Although winter will be mild it is still called winter for a reason so keep out the mittens till the spring!

For additional information and sources used please visit: http://www.noaanews.noaa.gov/stories2006/s2742.htm