Given the dramatic plunge in temperatures over the past few days, people in Wichita and around Kansas might be wondering what the coming winter will be like.
But El Nino is playing hard to get, and as a result forecasters are finding it more difficult to offer confident outlooks on the season ahead.
“This is one of the most challenging outlooks we’ve produced in recent years because El Nino decided not to show up as expected,” said Mike Halpert, deputy director of the National Oceanic and Atmospheric Administration’s Climate Prediction Center, in a prepared statement.
A weak El Nino could still form and influence weather patterns over the coming months, but in its absence seasonal forecasters are projecting this winter’s personality with even less certainty than usual.
The Climate Prediction Center is projecting a warmer than average winter for the western two-thirds of the country – including Kansas – and a dry winter for the upper Midwest and most of the country west of the Continental Divide. Precipitation levels will be about average for Wichita and Kansas, the center predicts.
Meanwhile, AccuWeather is predicting a warm and dry December for Wichita, with a snowy January and a mixed bag in February. The Farmers Almanac is predicting a milder than normal winter for Kansas, with average precipitation.
Overall, “it’s going to seem a lot colder,” said Jack Boston, expert senior meteorologist for AccuWeather.
But that’s because last winter was unusually warm in Wichita. Only 3 inches of snow fell, and the average winter temperature was the fifth warmest since the late 1880s.
Almost all of the precipitation that fell last winter came down as rain.
That happened, Boston said, because a weather pattern called the North Atlantic Oscillation was “open” last winter – meaning cold fronts stayed north of the Great Plains as they moved across North America. When pressure ridges “close” the oscillation at times, the fronts are pushed farther south into the continental U.S.
Forecasters are expecting more frequent “blocking” this winter, Boston said, but the more dominant feature that figures to affect Wichita weather is a strong southerly jet stream moving from Baja California across Texas and into the Southeast. Storms tracking up from the desert southwest often bring substantial snows to Kansas and Wichita, and Boston said Wichita could see a couple of major snows – say 6 inches or more – in January.
Wichita has averaged about 14 inches of snow a year over the past 30 years or so, according to the National Weather Service.
“It’s going to seem a lot more of a winter” compared to last year, “even though it won’t be an extreme winter,” Boston said.
Wichita recorded only five days on which the temperature stayed below 32 degrees last winter – less than a third of the annual average of 18 days, according to the National Weather Service. On average, there are 10 days each winter when the low temperature drops below 10 degrees in Wichita, but there were none last winter.
Overall, precipitation for the entire winter will likely wind up being below normal, he said.
“That’s mainly because of December,” Boston said.
Winter storms typically are the most difficult to forecast, meteorologists say, because even slight changes in temperatures and paths can have major impacts on what happens where. That naturally makes winter outlooks challenging as well.
Forecasters projected a warmer-than-average winter for Kansas and Wichita last year, with more sleet and ice instead of snow. While they were correct about little snow, temperatures were so much warmer than normal that the precipitation fell primarily as rain.
That proved a significant detail on at least two occasions, with heavy rains falling a few days before Christmas and in early February. Had temperatures been just a few degrees lower, forecasters have said, that precipitation would have taken the form of a major ice storm or a heavy snow.
The North Atlantic Oscillation played a key role in those situations, Boston said, because it didn’t force arctic air down into the Great Plains, setting the stage for significant snow events. Given the absence of snow cover in the northern Plains, he said, it was more difficult for truly cold air to make it as far south as Kansas.