Last year was the first time in memory you could look at the Seasonal Drought Outlook and see nothing but normal and above normal moisture conditions across the entire nation. That began to change in the Southeast and Texas last summer, and continues to change quickly.
According to the National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service, a moderately strong La Niña has kept storms and most of their precipitation in the North, leaving the South drier than normal.
“The speed with which the drought developed across the southern U.S. is rather unusual considering that just last year El Niño dominated the region with abundant precipitation,” says Bill Proenza, director of NOAA’s National Weather Service southern region. “Then it was as if a switch was flipped during the summer, changing to La Niña conditions.”
The NOAA folks say La Niña has developed 13 times since 1950, and the current La Niña ranks as the sixth strongest. The question climate experts are asking now is whether it will fade with the approach of summer or continue into next year.
So far, Texas and Florida are the most affected. From October through December, Texas received only 5-50% of normal precipitation, with portions of the lower Rio Grande averaging less than 5% of normal. In Florida, 51% of the state was in severe to extreme drought by the end of 2010.
The U.S. Seasonal Drought Outlook shows emerging and deepening drought across much of Texas and the Southeast, in eastern New Mexico and up through Oklahoma and Kansas, into eastern Colorado and western and southern Nebraska.
“Of the five stronger La Niñas that occurred, four resulted in multi-year events,” says Victor Murphy, climate program manager for NOAA’s National Weather Service southern region. “If this La Niña persists until next winter, the threat of drought conditions in the South extending into next year will be heightened.”
For more NOAA predictions, go to www.cpc.ncep.noaa.gov/products/.