The Florida Climate Center is predicting a high likelihood of a warm and dry fall, winter and spring for Florida and the Southeast United States, thanks to La Niña, said David Zierden, climate scientist at Florida State University’s Center For Ocean Atmospheric Prediction Studies (COAPS) and state climatologist of Florida.
La Niña is a state of the tropical Pacific Ocean where surface temperatures along the equator from South America to the central Pacific turn colder than normal.
La Niña is the opposite of El Niño, where the equatorial Pacific is much warmer than normal. La Niña favors a jet stream pattern over the United States that steers winter storms away from the Southeast.
“Crops in parts of the Southeast are already suffering from drought conditions,” said James O’Brien, emeritus Robert O. Lawton Distinguished Professor and former state climatologist, noting that southern Alabama, southern Georgia and the western Florida Panhandle are now designated as experiencing moderate to severe drought, according to the U.S. Drought Monitor. “A slow-moving tropical storm across the Southeast would do wonders for crops and water supply.”
“This is one of the poorest crops in many years,” said William Birdsong, regional agronomy specialist with Auburn University Extension, of the peanut and cotton crops in Southeast Alabama. “The situation is shaping up to be disastrous.”
Michael Ryshouwer of the Florida Department of Agriculture and Consumer Services said that the peanut crops in this region are in danger of being left in the ground, despite being nearly full-grown, due to the dry soil damaging the harvesting equipment.
La Niña and the anticipated dry conditions are starting to worry water resource managers in Florida, Zierden said. Tampa has only recorded 1.02 inches of rain in the month of September, 5.32 inches below normal.
“If we do not get significant rainfall in the next month, maybe from a tropical system, we can expect a long dry spell for the next seven to eight months,” said Alison Adams with Tampa Bay Water. “Tampa Bay Water is already preparing for the dry conditions.”
The expected dry pattern could hasten the return of widespread drought to the region. With a strong La Niña, the dry conditions tend to spread further northward and affect even northern Alabama and Georgia. Potential deficits in rainfall during the winter in these areas can be critical, as winter is the primary recharge season for surface and groundwater.
The impact of La Niña is already being seen in the Atlantic hurricane season.
The state of the Pacific Ocean in a primary factor in seasonal hurricane forecast from NOAA, Colorado State University and FSU.
The La Niña leads to more active hurricane seasons and the tropics have experienced a flurry of activity in the past few weeks. La Niña tends to favor hurricane paths that curve northward and threaten the East Coast of the United States.
La Niña also brings the potential for a very active wildfire season to the state of Florida.
Acreage burned is often more than double the average in La Niña years, as was seen in active seasons of 1998 and 2001.
Warmer temperatures may slow the necessary chill accumulation in flowering fruits such as blueberries, peaches, and strawberries but enhance development of other crops.
The forecasted warm and dry conditions are unfavorable for the production of winter forage for cattle when irrigation is not available.
While mild freezes can be expected every year in north and central Florida, La Niña reduces the risk of severe freezes in the citrus and vegetable belts.
The good news is that this winter should be good for tourists and lead to lower energy bills which is good for consumers and bad for energy companies, Zierden said.
Florida State is a member of the Southeast Climate Consortium, a partnership of eight universities in Florida and the Southeast aimed at bringing seasonal climate prediction to better use in the management of agriculture and natural resources in the Southeast United States. At FSU and the University of Florida, a new Florida Climate Institute has been approved to advise Florida citizens about climate forecasts.
El Niño, the better known warm phase of the Pacific Ocean, was in place last winter and brought a wetter than normal and colder climate pattern to the Southeast during the winter months. Following the El Niño, sea surface temperatures cooled to near normal in May and June but then continued their rapid decline and have now reached thresholds consistent with a strong La Niña.
La Niña typically brings fall and winter weather patterns to parts of the Southeast that are warmer and drier than normal. Historically, the peninsula of Florida averages rainfall 40 to 60 percent below normal in the months of November through March during La Niña events. Temperatures over the entire area average 3 to 4 degrees warmer than normal. The onset of warm and dry conditions normally begins in September and the pattern intensifies as the season progresses.
For more detailed information on La Niña and climate forecasts, see agroclimate.org and coaps.fsu.edu/climate_center.