Californian wildfires force evacuations this week.
California doesn't have much chance for rain in the next five months, and its best opportunity to break the drought there may hinge on the emergence of an El Nino in the Pacific Ocean this year, US forecasters said Thursday.
The entire state is suffering some form of drought, as is 38.1 per cent of the contiguous 48 states, according to the US Drought Monitor. As California's traditional rainy season has just ended, there won't be many chances for relief until October or November, said Mike Halpert, acting director of the US Climate Prediction Center in College Park, Md.
"Given that they are pretty much entering their dry season, it's a minuscule chance they will see any rains," Halpert said during a conference call with reporters. "Looking ahead to next winter, it will be somewhat dependent on the strength of this El Nino."
The drought in California, the largest US agricultural producer, has exacerbated wild fires burning in the southern part of the state and might force some farmers to abandoned fields as lack of water makes it impossible to grow crops.
Through the first four months of 2014, California and Arizona have experienced the hottest start to any year in records going back to 1895, according to the National Climatic Data Center in Asheville, N.C.
While the western US was warm from January through April, the East was colder, with an overall temperature in the contiguous United States of 0.4 degree Fahrenheit below normal, the coldest start since 1993.
The chance of an El Nino forming by the end of the year is about 80 per cent, Halpert said while discussing the year's start and summer outlook. However, predicting the intensity of the event is difficult.
In March, sea surface temperatures in the equatorial Pacific were the highest on record, surpassing 1997 when an intense El Nino formed. Since then, the readings have failed to keep up with the 1997 pace and researchers aren't sure this year will match that one in power.
An El Nino can make the southern half of the US wetter, while bringing dry, warmer conditions to the northern states throughout the winter.
An El Nino is defined by sea surface temperatures at least 0.5 Celsius above normal and a corresponding change in the atmosphere above the ocean. While the temperature reached that threshold last week, it hasn't been long enough to declare an event under way, Halpert said.
If those readings hold through May or get warmer, it's possible the US will declare next month that an El Nino is taking place, he said.
In addition to the El Nino and drought outlooks, forecasters also predicted the US East, West and Gulf coasts will probably have above-normal temperatures from June to August. The eastern Rocky Mountain states also may get above- average rainfall.