Winter 2010-11 Forecast!

The moment you have been all waiting for....the Winter 2010-11 Forecast! After much thought and research I have come up with a synopsis for how this Winter will play out. Through much of the Summer, we experienced a rather Neutral oscillation (neither El Nino nor La Nina). As of late, and through Spring 2011, the oscillation has switched to La Nina. What does this mean for our Winter season? A cold Winter ahead my friends. In terms of precipitation, There may be a few instances where we could have a significant snow/ice storm (which I will discuss further below), but otherwise it will be a dry season. 
Since this past October, La Nina has been driving the climate and will continue to do so through the next season. The reason researchers know and can forecast this is partially due to the sea surface temperatures (sst) in the Pacific Ocean. In general over the Pacific, the overall sea surface temperatures have been some 2.5 degrees below average. These colder temperatures are not only measured near the surface, but were also measured (from buoys) about a hundred meters below the surface further supporting La Nina for the season. Keep in mind, a climate oscillation is not an area that encompasses a certain area like a few kilometers or miles. This 'area' is larger then an airmass, if you can remember this from a few posts ago. This La Nina oscillation ranges from the International Date Line in the middle of the Pacific Ocean, across the the ocean, up to Canada and through the States in the Northern Hemisphere; a whole lot of an area! Such El Nino and La Nina events as partially due to Pacific Decadal Oscillation that causes temperature 'swings' over the globe which varies during a longer time scale the ENSO (El Nino Southern Oscillation). La Nina is the colder cycle of ENSO.
Other variables supporting this La Nina event is Convection over Indonesia, which has continued to enhance the lower level trade winds and the upper level westerly winds.   


From this event and overall weather patterns that can and will occur during this coming season, research and past climate events generally give an idea temperatures and precipitation specifically over North America. This  Winter season, the following will occur: (Close your eyes and picture a map of the U.S. If you simply can't, there is a map below to cheat).

Courtesy of NOAA

-  Below average temperatures over Southern and Central Alaska, along the coast of California, running up North along the Northern parts of the States: Washington State to Minnesota, including Canada.
- Temperatures in the along the Rockies, Southwest, Texas, through the Southern and Central Plains, as well as the Mississippi River Valley will be above average. 
- Central Atlantic States through New England will experience a combination of both. The above average temperatures could slide as North as the Delmarva (Delaware and Maryland area). Our weather will be highly dependent on the direction of the Wind. Southwesterly winds will give is milder temperatures. Winds out of the North will give us the coldest temperatures. New Jersey, Pennsylvania, and New York will be rather variable in terms of weather this Winter. Because we are located in such a vulnerable spot, we could be subject to a storm or to and especially the biting cold temperatures. 


- Precipitation in the Northwest will/could be above average. This includes northern parts of California. 
- Other areas of above average precipitation include parts of the Northern Rockies (North as in location, not elevation), Ohio, Indiana, Kentucky, and the Southern Great Lakes. Areas surrounding the Great Lakes could possibly experience some of the greatest snow, especially when the 'snow machine' gets started. This depends on how soon and long this colder air sticks around. Remember, the warmer the lakes remain, the greater the chance for snow, and a lot of it. 
- From Southern California, parts of the Southwest, Texas, and through the Gulf States, below average precipitation is expected. 
- This below average precipitation again, reaches up along the Central Atlantic states to the Delmarva. Again, New Jersey, Pennsylvania, and New York are on the boarder line. 


This Winter season for the most part looks to be quite exciting, but not to mention a potential nightmare for we forecasters when it it comes down to predicting storms in our area. It will come down to the dreaded '540 line.' This line is know as a thickness value in the atmosphere. 540 stands for 5400 geopotential thickness between the atmospheric layers between 1000 mb (also known as the surface) and 500 mb. Thickness is the idea of the temperature and the moisture content of the air through this layer. We use this 'line' as a reference when forecasting the type of precipitation during the Winter months. 


Stay warm this Winter and remember to bare with us when forecasting your Winter weather...it's a tough job predicting Mother Nature!


~ V.S.