La Niña will make encore appearance
La Niña is forecast to make an appearance on the Northern Plains this fall and winter according to the latest National Oceanic Atmospheric Administration Climate Outlook released on October 20, 2016.
“There is about 70 percent certainty that La Niña will affect the U.S. climate this fall, according to the Climate Prediction Center,” explained Laura Edwards, Acting State Climatologist & SDSU Extension Climate Field Specialist.
Edwards added that forecasters are about 55 to 60 percent sure that La Niña will carry through the winter season.
The latest national temperature and precipitation outlook reflects a typical La Niña signature over the U.S. for the winter season.
“In South Dakota, this has historically meant colder than average temperatures, especially in December and January,” Edwards said.
As far as precipitation is concerned, she said there is less certainty in the Dakotas. “In the past, it has been wetter in the northern Rockies and over the Great Lakes region, with La Niña,” Edwards said. “One thing is for sure, this year’s La Niña is forecasted to be a weak event, which means less certainty in the winter climate outlook.”
In the meantime, warmer than average temperatures are more likely through November, before potentially turning colder. “The next couple of weeks may be wet, but then much of the eastern Dakotas are likely to turn drier or end up closer to average precipitation through the end of November,” Edwards said.
Edwards pointed out that there are many other factors which can affect our wintertime climate. “Particularly the temperatures in the Arctic or northern regions of Pacific and Atlantic Oceans. These can affect where the jet stream settles in this winter,” she said, explaining that generally, these shorter-term climate patterns set in for a few weeks at a time. “This makes them difficult to project months in advance.”
So far this fall, South Dakota has enjoyed warmer than average temperatures, and generally dry conditions.
“This has been good news for corn and soybean farmers, especially those in the southeast who had some wet weather late in the season,” Edwards said.
Fire danger has also increased due to these same dry and warm conditions.
The Cottonwood Fire on October 17-19, 2016 was unofficially the fifth largest in the state’s history, with a total burn area of more than 41,000 acres.