GET ready for a wet winter and an even wetter spring.

Japanese climate scientists' latest computer forecast shows a "fairly strong" La Nina developing across the Pacific Ocean this winter.

Japan Agency for Marine-Earth Science and Technology senior scientist Jing-Jia Luo said the El Nino would soon end, followed by a strong La Nina, to bring a wetter winter and spring conditions across eastern Australia.

"Eastern Australia would have more precipitation than normal during May to August, 2010," Mr Jing-Jia said.

Farmer confidence in the Japanese model has grown in recent years, particularly after the JAMSTEC team leader Prof Toshio Yamagata reliably predicted the continuation of the drought in May 2007.

The latest forecast uses the sea-surface temperature differences across the Indian Ocean to indicate the likelihood of rain in Australia's southeast.

The temperature differences are compared to historical averages to calculate the Indian Ocean Dipole effect. The dipole moves into positive territory when the sea surface temperatures off the Australian west coast are cooler than average, resulting in less evaporation and less moisture in the northwest jet stream crossing the continent and thus less rain.

However, their latest forecast predicts the dipole will move into negative territory in spring indicating wet conditions in Australia.