2011-2012 WeatherBug Winter Outlook
UPDATED December 1, 2011
UPDATED By WeatherBug Meteorologist, Dustin Devine
Meteorological winter started Thursday and WeatherBug Meteorologists believe a combination of several factors, including a return to a weak La Nina, will contribute to warmer than average temperatures along much of the U.S. Southern-Tier; Meanwhile, cooler than average temperatures will be common across the U.S. Northern Tier.
WeatherBug Senior Meteorologist James Aman presented the WeatherBug Winter Outlook in a webinar that can be viewed here.
La Nina, the abnormal cooling of the Pacific Ocean off South America`s west coast, tends to alter climate patterns a bit and shifts North America`s jet stream of high-altitude winds. While La Nina typically cycles back-and-forth every 3 years or so, it`s not totally bizarre to see it return within a year`s time.
A weak to moderate La Nina this winter will likely keep the Southern Tier drier than average, allowing the extreme drought to continue in Texas and Southwest. The dry weather could also fuel an increase in wildfires. Drought conditions plaguing the Southeast will likely continue through the winter as well with precipitation a bit scarce in this region, too.
In a typical La Nina pattern, winter storms parade off the Pacific into the Northwest and Rockies, dropping heavy rain and mountain snow, leading to above average precipitation. WeatherBug forecasters are calling for the greatest probability of above average precipitation in western Washington, northern Oregon and into the Northern Rockies.
In addition, there are strong signals for more frequent winter storms in the Midwest and Ohio Valley. For much of the California Coast, temperatures will likely be cooler than average and precipitation near to slightly above average.
Other factors considered in the official WeatherBug Winter Outlook include the North Atlantic Oscillation, which is responsible for sending cold blasts into the East. While this variable is much less predictable more than two weeks in advance, there are signs it will fluctuate a great deal this winter. This will lead to cold blasts quickly followed by warmer spells that will allow temperatures to top off near average.
Although it won`t have a pronounced impact on East Coast temperatures this winter, cooler waters forecast off the Mid-Atlantic and Southeast Coast could favor periods of below average temperatures for adjacent inland locations. Just the opposite in New England with above average sea surface temperatures forecast off the New England Coast could spell warmer periods for inland locations like Boston.
Be sure to keep WeatherBug active to receive the latest weather in your neighborhood and get the latest updates anywhere on Twitter
What do you think of this story?
for comments or suggestions.