A U.S. government weather forecaster on Thursday raised its forecast for the chance of El Niño conditions during the Northern Hemisphere summer to 70 percent, up from a 60 percent chance last month, with a 60 percent chance it lasts through autumn.

The Climate Prediction Center, an agency of the National Weather Service, in its monthly report noted that El Niño conditions were apparent by the end of March, citing above-average sea surface temperatures across the equatorial Pacific, though they remained weak.

These conditions were likely to persist throughout 2015, the CPC said, though it said there is considerable uncertainty as to how strong the event may become.

El Nino, the warming of Pacific sea-surface temperatures, can trigger drought in some parts of the world and cause flooding in others.

The CPC said in the report that beginning in May, its monthly report will be released on the second Thursday of each month.

(Reporting By Luc Cohen; Editing by Chizu Nomiyama and W Simon)