Abnormally dry conditions return to parts of Georgia

Following a wet winter and early spring, Georgia’s summer has been generally hot and dry. Much of northwest, north-central, southwest, east and coastal Georgia are abnormally dry. Over the past month, less than half of normal rainfall has fallen in some of these areas.

Over the past two months, many areas in Georgia have received only 70 percent of normal rainfall. For this month through July 19, Athens has received 42 percent, Augusta at Bush Field 29 percent, Columbus 44 percent and Savannah 44 percent of normal rainfall.

Counties in northwest and north-central Georgia currently classified as abnormally dry are Haralson, Polk, Bartow, Cherokee, north-Fulton, Forsyth, Dawson, Lumpkin and Union, inclusive.

In southwest Georgia, counties classified as abnormally dry are Muscogee, Chattahoochee, Stewart, Webster, Sumter, Crisp, Lee, Dougherty, Baker, Decatur, Grady, Thomas and Brooks, inclusive.

In coastal and east Georgia, counties classified as abnormally dry are Madison, Elbert, Clarke, Oglethorpe, Wilkes, Lincoln, Taliaferro, Warren, McDuffie, Columbia, Richmond, Burke, Wilcox, Ben Hill, Dodge, Telfair, Laurens, Wheeler, Montgomery, Treutlen, Emanuel, Jenkins, Candler, Evans, Screven, Bulloch, Effingham, Chatham, Bryan, Liberty, Long, McIntosh, Wayne, Glynn, Brantley and Camden.

Exceptions to the drying trend include much of the central and west piedmont and the north-central and south-central coastal plain. Atlanta has received 102 percent of normal rain over the past month. Macon has received 234 percent of normal rain over the past month.

With temperatures remaining in the 90s and low 100s with little or no rain, soils statewide will continue to dry. This will lead to increased plant stress.

As of late July, stream flows and reservoir layers are near normal to above normal across the state. Water resources are anticipated to be near normal over the next few months.

The ocean-atmosphere system has switched into a La Niña pattern. According to the Florida State University’s Center for Ocean-Atmospheric Prediction Studies, the La Niña pattern increases the likelihood that the East Coast will experience a land-falling tropical system compared to normal. If an active tropical storm season develops as forecasted, dry conditions could be relieved by summer and fall tropical systems.

However, the La Niña pattern is associated with dry and warm winters across much of the Southeast. This means that we may have minimal recharge of the hydrologic system this winter. This increases the probability of widespread and significant drought for next year. It is too early to tell exactly how the La Niña pattern will impact Georgia, but we need to be aware of the possible short-term tropical impacts and the long-term drought impacts.

Up-to-date information on dry conditions across Georgia can be found at www.georgiadrought.org. Updated weather conditions can be found at www.georgiaweather.net.




By David E. Stooksbury
University of Georgia

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Georgia's summer likely warmer, drier than normal

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.

Tropical question

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.

Transition time

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 that atmosphere will be near transition to or in a La Niña by the heart of hurricane season.

As Georgia enters the winter, it appears that we will be in a La Niña climate pattern. Typically this means that south Georgia can expect winter 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.
Up-to-date weather information is available at the website www.georgiaweather.net. Historic climate data is available at the website climate.engr.uga.edu.

By David E. Stooksbury
University of Georgia

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