Wet and warm are growing conditions that Alabama producers are familiar with. However, producers are not accustomed to warm, wet winter weather which seems to be on the agenda for Alabama.
The National Weather Service (NWS) has released the winter forecast and predicts climate will be under the influence of the La Niña phase of the El Niño-Southern Oscillation (ENSO). ENSO is an ocean-atmospheric phenomenon that affects the temperature and precipitation in the Southeast, including Alabama.
Alabama Cooperative Extension System Precision Agriculture Specialist, Brenda Ortiz, said the signals for a La Niña winter are strong. She is encouraging producers to pay attention to the climate patterns as they prepare for winter crop planting and management.
About ENSO
ENSO is the interannual fluctuation of the atmosphere-ocean system in the equatorial Pacific, and it has three phases: warm (El Niño), cold (La Niña), and Neutral. The NWS anticipates a La Niña winter—which means significantly warmer weather for Alabama. It also includes rainfall expectations above average in northwest Alabama and below average in southern counties.
A number of international science agencies work cooperatively to monitor the ENSO system. Data collected worldwide helps characterize the strength of each ENSO phase, as well as predict changes over time.
Ortiz said the predictions can tell experts which climate variations to expect, even several months in advance.
“Scientists use these predictions to anticipate the impacts that will occur during the months that follow the onset of one of the weather events,” she said.
Impacts on Alabama Farms
Because the impact of ENSO is stronger during the winter, the absence of cold weather can have an effect on pest and disease pressures, aquifer refilling and crop growth—including both winter crops and fruit crops.
Ortiz said with advance notice, there are some things producers can plan ahead for.
“The influence of either La Niña or El Niño on the southeastern climate does not usually last a full year,” she said. “However, if the signal is very strong, the influence could last more than a year. Farmers should track the NOAA forecast in case the strength of La Niña increases. Historic records of previous strong La Niña events are corrected to the most severe droughts in the Southeast (1974 to 1976, 1999 and 2001).”
On average La Niña brings more rain to northwest Alabama during the winter months, so stream flows are higher which enables farmers to pull more water into their irrigation ponds.
She said producers in northwest Alabama can expect warm and wet conditions. The rest of the state can expect warm, dry conditions to persist throughout the winter. These predictions are based on the general characteristics of the La Niña phase of ENSO.
La Niña Characteristics
- Duration – La Niña can last for one to three years.
- Weather Events – The likelihood of tornadoes and severe weather increases in Alabama and Georgia.
- Precipitation – Falls are slightly drier than normal in the northern part but slightly wetter in the other parts of the state. Winters are drier in the central and southern parts but wetter in the northern part.
- Temperature – Falls are slightly warmer in the southern part but not different from normal in the northern and central parts. Of all phases, La Niña is the warmest in the southern part. Winters are warmer in all locations of the state. However, temperatures are warmer in the south than in the north.
Source : aces.edu