WASHINGTON (AP) - The La Nina climate phenomenon has returned and that could be bad news for the drought-ravaged south central states.

The periodic cooling of the tropical Pacific Ocean can affect weather worldwide and often results in drier-than-usual conditions across the southern tier of the United States and wetter than normal conditions in the Pacific Northwest and Ohio Valley.

Mike Halpert, deputy director of the federal Climate Prediction Center, says ``this means drought is likely to continue in the drought-stricken states of Texas, Oklahoma and New Mexico.''

The forecasters said La Nina contributed to extreme weather around the globe during the first half of this year and then faded.

They say it's now re-emerged and is expected to gradually strengthen and continue into winter.