La Niña expected to influence winter climate 2021-22 | Community

BROOKINGS – La Niña conditions have been officially declared this season by the National Oceanic and Atmospheric Administration (NOAA), but what does that mean for South Dakota’s winter climate, and the outlook for this year in particular? ?

Laura Edwards, an extension state climatologist at South Dakota State University (SDSU), said the hot and humid conditions this fall have left many wondering what winter might be like. of South Dakota.

“The holiday season is here and people are making their wish lists,” Edwards says. “Some dream of a winter wonderland with children hoping for snowy days. Others want cold temperatures that can freeze the ground when calving begins later in the season. Still others are keeping their fingers crossed that there is enough humidity to prevent the return of a severe drought in 2022. “

Edwards says whatever you fancy there could be something for everyone this winter. The end of November and the beginning of December are expected to see near normal to warmer than average temperatures. At the same time, the odds tilt toward near-normal chances of drier-than-average precipitation.

“There is a fair amount of uncertainty among climate model predictions for the coming winter, which could mean both cold and hot spells, as well as snowy and dry conditions fluctuating throughout the season.” , said Edwards.

The outlook for December and December through February was released by NOAA on November 18. This outlook indicates uncertainty regarding the winter season precipitation in the Northern Plains region, including South Dakota.

“While the Northwestern and Great Lakes regions are preferred to be wetter than average over the next three months, the Dakotas fall in the middle with equal chances of wetter, drier, or nearer rainfall. average over the same period, ”said Edwards. “Southern states are preferred for being drier than average. This general trend in the United States is consistent with the winter climatology of La Niña, which is expected to reach moderate strength in the coming months. “

While the temperature outlook for December shows extreme southwestern South Dakota with slightly improved chances of warmer-than-average conditions, the rest of the state has equal chances of warmer, cooler, or close to the average for the whole month.

“As winter progresses, colder-than-average temperatures become more likely in the northwest, northern Rockies and western Dakota. Historically, the cold period of La Niña in our region occurs most often and is at its strongest in February, ”says Edwards. “The temperature outlook for December through February reflects this historical pattern, with the southern and eastern states more likely to experience warmer than average conditions.”

Edwards says that while La Niña offers the best forecasting tool for this winter season, there may be other factors at play, such as atmospheric circulation patterns over the Arctic and North Atlantic Ocean. .

“There is a lot of variability with the impacts of La Niña on South Dakota, but historical averages have shown that a colder than average temperature at the end of winter is more likely. La Niña does not correlate very well with winter precipitation or snowfall, so there is still a lot of uncertainty, ”said Edwards. “One thing to consider is that late winter snowfall could stay on the landscape longer than usual if cold temperatures prevail in late winter / early spring. “

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