Many producers in the Southeast have had ideal planting conditions this year, with showers spaced far enough apart to get the crops in the ground on time and up to a decent stand. But forecasters warn that the end of El Niño could mean drier conditions as we enter the summer months.
After reaching moderate to strong levels in December and January, El Niño has faded over the last two months, according to the Summer Climate Outlook issued by the Southeastern Climate Consortium (SECC).
El Niño refers to a periodic (every two to seven years) warming of the tropical Pacific Ocean along the equator from the coast of South America to the central Pacific. This past El Niño can be considered a strong event and was certainly the strongest El Niño since the great one in 1997-1998, says the SECC report. Ocean surface temperatures warmed to nearly 2 degrees C higher than normal in the El Niño region during the peak of this past event in late December.
Since late December, the El Niño began losing strength, but remained at moderate to strong intensity throughout the winter and into the month of April.
“In the last few weeks, the decay has occurred more quickly and sea surface temperatures are now very close to normal across the entire region. When sea surface temperatures are close to normal as they are now, the Pacific Ocean is classified as in a neutral phase,” states the outlook.
One to three months of neutral conditions is the most likely forecast right now with a wait-and-see attitude on the possibility of La Niña developing later this summer. “We can say that return to El Niño is highly unlikely for the remainder of 2010,” says the SECC.
(For a look at how critical weather forecasting is to Southeast growers please visit http://southeastfarmpress.com/news/weather-situations-0426/index.html)
El Niño is known for bringing frequent storminess and excess rainfall to parts of the Southeast during the winter months and this past year has been no exception. In November through March El Niño typically leads to rainfall 40 to 50 percent greater than normal over the peninsula of Florida and up to 30 percent greater than normal over coastal Alabama, south Georgia and coastal North and South Carolina.
“The only thing atypical about rainfall patterns this past winter and early spring is that the above-normal rainfall extended all the way to northern Alabama and Georgia instead of only affecting the coastal areas,” according to the SECC.
El Niño also exerted its influence on temperatures this winter. Winter temperatures averaged 3 to 5 degrees F. below normal across the Southeast, resulting in greater chill accumulations than in normal years. Parts of the Southeast, especially Florida, also experienced some of the coldest temperatures since 1985. The first half of January featured an extended freezing spell, where Tallahassee recorded a record 14 consecutive days below freezing.
Although the connection between El Niño and rainfall usually diminishes in April, this past spring saw a continuation of rainy weather well into the spring. “All of this extra winter and spring rainfall has had the beneficial effect of recharging soil moisture, surface water and groundwater heading into the summer growing season,” states the outlook.
While El Niño may be over, effects could linger into the summer, according to the forecasters. “The analysis of past El Niño events show the following late spring/early summer period often turns somewhat drier than normal,” they say.
Typical June rainfall patterns indicate that most of North Carolina, Alabama and parts of Georgia — in a post-El Niño summer — can be 5 to 20 percent drier than normal. “A word of caution, summer rainfall patterns in the Southeast are still quite unpredictable and the connection to El Niño is nowhere near as strong as in the winter months, when such predictions are much more certain,” states the report.
In north Alabama, north Georgia and the Carolinas, the spring potentially brings the last chance of meaningful recharge for surface and groundwater. “Evapotranspiration exceeds normal rainfall during the summer months, so winter and spring recharge received this year is important for water resources. During the summer, the Southeast is characterized by hot, humid conditions and convective thundershowers. Coverage and frequency of these afternoon thunderstorms is higher in Florida and extreme South Georgia, but more ‘hit and miss’ in the remainder of Georgia, Alabama and the Carolinas,” according to the SECC report.