(Reuters) - Heavy rainfall could bring flash flooding to Arizona and New Mexico, the National Weather Service said on Wednesday, as severe weather associated with weakening Tropical Storm Odile sweeps across the drought-stricken U.S. Southwest.

Weather forecasters warned that as much as 9 inches (23 cm) of rain could fall on some communities by Thursday night, with 3 to 6 inches (8-16 cm) expected across much of the desert region.

"This could be one of the wetter tropical cyclones they have ever had in that area," said David Roth, a forecaster with the NWS Weather Prediction Center in Maryland.

Earlier in the week the storm trapped thousands of tourists and smashed shops, leaving them open to looters in Mexico's Baja California region.

Flash flooding also is a possibility in the southern regions of Nevada and California, as well as around El Paso in far western Texas.

The warnings of another downpour follow powerful storms that recently dumped record rainfall on the Phoenix and Tucson areas.

Arizona Governor Jan Brewer declared a state of emergency after last week's drenching turned sections of major freeways into lakes, overflowed from creeks and canals and killed two women swept away by flood waters.


(Reporting by Letitia Stein in Tampa, Florida; Editing by Scott Malone and Bill Trott)