The National Oceanic and Atmospheric Administration said Wednesday the nation's drought is the worst in 32 years but there is no conclusive evidence the dry weather is caused by the global warming trend.

NOAA's Climate Office concluded, "The present situation is the most widespread, severe drought in the continental United States in over 30 years, and prospects for an early end are not promising."The report noted that the present drought actually began in the Southeast and West two to four years ago. By the end of June, 35 states reported extreme drought conditions.

"Nearly 29 percent of the continental United States is experiencing severe or extreme drought," the Climate Office said. Similar conditions covered nearly 40 percent of country during June 1956, the most recent drought of comparable magnitude.

Three drought years in the dustbowl of the 1930s brought severe or extreme conditions to more than 35 percent of the United States, with 1934 bringing such drought to 61 percent of the nation.

The proximate cause of the drought is "a stable, high-pressure air mass with descending air," low humidity, and few clouds that has parked itself over North America.