WASHINGTON, Oct. 15, 2015 - An historically strong El Nino this winter is likely to bring some relief from California’s prolonged drought while providing wetter, cooler weather across the southern Plains and Southeast.
According to the National Oceanic and Atmospheric Administration’s winter weather outlook, the Pacific Northwest is unlikely to get any help with its ongoing drought, while the northern Plains and northern Midwest could be warmer and drier than average.
“El Nino is often a positive for the U.S., contributing to beneficial rains across the South and a milder than average winter in the North,” he said.
The expected precipitation in southern and central California should provide some improvement in drought conditions by the end of January and some additional relief is possible in February and March.
More than half of the state is considered to be in an “exceptional drought,” due to four straight years of below-average precipitation. “If the wettest year were to occur we still wouldn’t erase the deficit that’s built up over the last four years,” Halpert said.
The cumulative deficit in precipitation is equivalent to as much as three times the average annual precipitation in the region.
El Nino events also have been associated with more severe storms. which means that “while we’re still dealing with severe drought in California, we’ll also be dealing with severe flooding at the same time. That’s not unheard of,” Halpert said.
As of August, California’s cumulative rainfall deficits since October 2011 ranged from 8 inches in the southeastern part of the state to nearly 50 inches along the northern coast. Every region of the state is down the equivalent of at least a year’s worth of precipitation.
According to the seasonal drought outlook, also released Thursday, the best chance for drought improvement in California is across the coastal regions and valleys. In the Sierras, improvement depends on colder temperatures to ensure substantial snowfall.
Much of the drought conditions that linger from Texas to Alabama will likely be eliminated this winter, NOAA says.
The expected high temperatures, meanwhile, will limit snowpack in the Pacific Northwest, and the drought is expected to expand eastward across the northern Rockies and possibly the northern Great Plains.