Published on 02/22/00

Blame Long Drought on La Niña

`Long Georgia Drought Expected to Worsen´

La Niña can explain the prolonged drought that began in Georgia in May 1998. While you can't blame La Niña for the weather on any given day, it is responsible for the general pattern. It has influenced the state's climate since mid-1998.

In the La Niña pattern the sea surface in the equatorial Pacific Ocean is abnormally cold. During La Niña, Georgia normally has below-normal winter precipitation and above-normal winter temperatures. That's been true statewide in the winter of 1999-2000.

The CPC's February La Niña advisory reports that strong cold-surface conditions continued in the equatorial Pacific during January 2000.

La Niña Expected to Weaken

The current La Niña is in a mature stage. CPC computer models and statistical predictors expect La Niña to slowly weaken over the next several months. Surface temperatures figure to be near neutral to slightly cool during the second half of 2000.

An El Niño pattern may slowly develop as La Niña weakens. In this pattern, the equatorial Pacific surface is abnormally warm.

CPC reports that the subsurface temperature pattern in the equatorial Pacific is starting to evolve into the build-up stage for an El Niño pattern. The build-up period usually takes one to two years.

First Sign Drought's End May Be in Sight

This change in the ocean temperature pattern is the first sign that the drought's end may be in sight. However, it will be late summer before we can expect much of a chance of relief.

While it is too early to forecast the start of the next El Niño, late 2001 or early 2002 are reasonable estimates. El Niño winters in Georgia are associated with above-normal precipitation and above-normal temperatures.

David Emory Stooksbury is associate professor of Biological and Agricultural Engineering at University of Georgia's College of Agricultural and Environmental Sciences.