Created: Wed, 27 Nov 2013 10:05:00 EST
Updated: Wed, 27 Nov 2013 10:34:39 EST
It's hard to believe that winter is right around the corner! For meteorological purposes, winter actually begins December 1st. Astronomical winter begins on December 21st this year which will mark the winter solstice.
I've spent the last few weeks analyzing various weather data and long term trends and relating them to central Georgia. This year's winter forecast isn't as clear cut as years past because there isn't one key pattern that sticks out that would easily determine what we would expect during the winter months.
For this year's winter forecast, I took into account three variables: the current U.S. snow cover, the current Arctic sea ice extend and current trends for any potential development of El Nino or La Nina.
Let's examine the U.S. snow cover first. As of late November, over one third of the United States is covered with snow (35.8%). Snow cover for the same time frame in 2012 was only 19.6%. That means snow cover thus far is nearly double what it was a year ago.
Secondly, we'll examine the extent of Arctic sea ice and why that's important. Based on current data, arctic sea ice is actually growing at a rate that is above average. The amount of arctic sea ice currently in place is ahead of 2012 by 424,000 square miles. Through late November, the extend of the arctic sea ice ranks second highest since 2008.
The amount of U.S. snow cover and arctic sea ice is important because air masses travel over both before reaching the United States. Both act as a refrigerator, keeping the air colder for longer. Less snow cover and arctic sea ice allows air masses to warm as they move south.
The third variable for my winter forecast is whether an El Nino or La Nina will develop. El Nino occurs when water temperatures off the west coast of South America are warmer than average. La Nina is the opposite of El Nino, meaning water temperatures would be below average off the west coast of South America. Based on current data, we remain in a neutral pattern. That means neither El Nino or La Nina exist. Current forecasts indicate a trend towards El Nino by Spring, which suggests we will remain in a neutral state through this winter.
Below shows what each pattern produces in the winter months in central Georgia:
El Nino: Colder and wetter than average with above average snowfall.
La Nina: Warmer and drier than average with below average snowfall.
Neutral: Average temperatures with slightly above average precipitation and average snowfall.
Let's put it all together! Here's the bottom line for Jeff's Winter Forecast for 2013-14:
Temperatures: Expect at or slightly below average temperatures thanks to increased arctic sea ice and U.S. snow cover. As air masses venture south, they will stay colder longer, leading to the potential for below average temperatures all winter. That also follows the trend of below average temperatures we have seen for much of 2013.
Precipitation: Based on the current neutral pattern with forecasts trending towards El Nino by Spring, I suspect we will see a wet winter with above average precipitation. This includes any rain and snow. Precipitation is the key word.
Snowfall: Based on the current neutral pattern and the likelihood of below average temperatures, I suspect we have the opportunity for some snow. I think totals will follow the last 10 year average which would suggest a season total of 1/3". That is based on data at the Macon airport. Because of geographic location, areas north of Macon tend to pick up more snow than the Macon area.
What do you think? Post your comments below. You can find Chief Meteorologist Jeff Cox on Facebook by searching 'Jeff Cox' and on Twitter by following @WXManJeffCox.