Worsening Drought Is Forecast for Southwest US

(July 16) -- Weaker than normal monsoon rains in the American Southwest sparked a government warning that droughts already afflicting Arizona, New Mexico and neighboring states could get worse through the peak summer months.

Unseasonably hot and dry conditions have also produced "extreme" drought conditions in northern Louisiana and other parts of the Lower Mississippi Vally region, while record heat and irregular rainfall are troubling the mid-Atlantic and Appalachians, the National Oceanic and Atmospheric Administration's weather-prediction service said today.

NOAA

A map shows predicted drought conditions for parts of the U.S. this year. Federal scientists say Arizona and New Mexico will be the hardest hit.

But the most severe drought conditions this summer are centered on Arizona and New Mexico, with California and Nevada suffering as well.

"If the monsoon remains erratic during the next few weeks, then the drought development area may be expanded" next month, said Wayne Higgins, director of the NOAA Climate Prediction Center.

The Arizona state DroughtWatch service is reporting unusually low water levels in reservoirs, lakes and ponds; soil erosion due to the loss of plants and other vegetation; a dearth of water resources for livestock; and unusual levels of plant disease or insect infestations related to drought.

NOAA scientists blamed in part the unusually cold La Nina temperatures in equatorial parts of the Pacific Ocean, which affect U.S. climate patterns in ways that produce hotter, drier weather in the Southwest and typically occur every three to five years.

And the effects could linger.

"Beyond this time period, expected dryness associated with established La Nina conditions may bring further expansion of drought conditions in the Southwest during the 2010-11 winter season," Higgins said.

La Nina may also produce wetter-than-normal conditions in the Pacific Northwest this fall and through the winter, the NOAA said.