The Climate Prediction Center, a National Weather Service agency, last month forecast an 80 percent chance that conditions would last through early spring. The CPC still says there is a more than 90 percent chance that El Nino conditions would last through the Northern Hemisphere winter.

The new forecast marginally raises the risk that the El Nino phenomenon, the warming of Pacific sea-surface temperatures, will unleash a period of extreme and potentially damaging weather across the globe.

Past instances have caused heavy rains and floods, hitting grain crops in South America, and scorching weather as far as Asia and East Africa.

But one potential El Nino beneficiary could be California, where record-low rainfall has prompted water usage restrictions and contributed to the spread of devastating wildfires.

“It definitely would increase the likelihood of heavy rains in the winter there, which would certainly improve their situation tremendously,” said Donald Keeney, senior agricultural meteorologist with Maryland-based MDA Weather Services.

California could begin to get increased rainfall as early as October and definitely by November or December, Keeney said.

Rainfall will probably not increase in the Pacific Northwest states of Oregon and Washington, which are also suffering from droughts, although they could experience higher temperatures like much of the northern United States, Keeney said.

The CPC said the effects of El Nino were likely to remain minimal across the contiguous United States for the rest of the summer but would increase into the late fall and winter.

El Nino would probably contribute to a below-normal Atlantic hurricane season, the CPC said. That would reduce the likelihood of storms disrupting energy operations in the Gulf of Mexico.

However, the agency said El Nino was likely to lead to above-normal hurricane seasons in both the central and Eastern Pacific hurricane basins.