Georgia’s summer will likely be warmer and drier than normal through at least early August. Temperatures and rainfall in late summer and early fall will depend on the number and tracks of tropical weather systems.
The early summer following an El Niño winter climate pattern — like we had this past winter — is typically warmer and drier than normal. With the warmer temperatures and drier-than-normal conditions, soil moisture will quickly decrease over the next two months. However, because of the abundant rain this past winter and early spring, water resources are expected to remain in good shape across the state through this summer.
(For an extended outlook for the entire Southeast visit http://southeastfarmpress.com/news/southeast-weather-0610/index.html.)
By August the Southeastern U.S. will be entering into the heart of the tropical storm season. Will temperatures remain high and rainfall low? At this point, it’s hard to say. Again, this will depend on tropical weather systems. At this time, we do not have the ability to forecast the tracks of tropical storms this early in the season. We can only give general forecasts of the number of storms.
The number of tropical storms this summer is expected to be above normal. Atlantic Ocean and Gulf of Mexico sea surface temperatures are currently above normal. This favors the formation of tropical systems, including tropical depressions, storms and hurricanes.
An additional factor favoring the development of tropical systems is the atmosphere transitioning from an El Niño climate pattern to a neutral climate pattern. Neutral and La Niña climate patterns favor the formation of tropical weather systems. The oil spill in the Gulf of Mexico is not expected to have any impact on the number nor on the intensity of tropical weather systems.
An El Niño climate pattern typically transitions into a neutral pattern for several months. However, it appears that the ocean-atmosphere system will only spend a few months in the neutral pattern before changing into a La Niña pattern.
Historically, the East Coast, including Georgia, is more likely to be directly impacted by hurricanes when the atmosphere is in the La Niña climate pattern. There is a good chance the atmosphere will be near transition to or in a La Niña by the heart of hurricane season.
As Georgia enters the winter, it appears we will be in a La Niña climate pattern. Typically this means that south Georgia can expect winter weather to be warmer and drier than normal. Across north Georgia, a La Niña climate pattern generally brings a warmer-than-normal winter. For north Georgia, a weak La Niña climate pattern is associated with near-normal to wetter-than-normal winters. However, a moderate to strong La Niña climate pattern is associated with drier-than-normal conditions across north Georgia.
It is too early to know if this winter will bring a weak, moderate or strong La Niña climate pattern. If the La Niña climate pattern develops this winter, then Georgia may be set up for a drought in 2011.
EDITOR’S NOTE — David Stooksbury is the state climatologist, a professor of engineering and graduate coordinator for atmospheric sciences in the University of Georgia College of Agricultural and Environmental Sciences.