A structure sits damaged by flooding after a storm in Index, Washington in this Nov 19, 2015, file photo. [Photo/Agencies]

NEW YORK - A US government weather forecaster on Thursday said the El Nino weather phenomenon that is underway is expected to remain strong through the Northern Hemisphere winter 2015-16, before tapering off during the late spring or early summer.

The Climate Prediction Center (CPC), an agency of the National Weather Service, in its monthly forecast broadly maintained its outlook for strong El Nino conditions likely to persist through the winter.

"El Nino has already produced significant global impacts and is expected to affect temperature and precipitation patterns across the United States during the upcoming months," CPC said.

The phenomenon is a warming of ocean surface temperatures in the eastern and central Pacific that occurs every few years, triggering heavy rains and floods in South America and scorching weather in Asia and as far away as east Africa.

Japan's weather bureau said earlier Thursday that El Nino is now at its peak and weather would return to normal by summer.