Sep. 20—It was hot Saturday night, as Mitchell set its record for the day's warmest low temperature at 73 degrees. Although fall is fast approaching, meteorologists say South Dakota can expect an above average autumn without much rain.
Ryan Vipond, a meteorologist with the National Weather Service (NWS) in Aberdeen, said that meteorological fall, which officially began Sept. 1, tends to bring cooler temperatures to the state — but warned this year likely won't be typical.
Though a cooldown after Monday's showers can be expected to hold out for most of the week, with forecasted temperatures wavering between 70 and 80 degrees — teasing Midwesterners with a taste of fall before heating back up again.
The Climate Prediction Center currently predicts above average temperatures to begin impacting South Dakota in its six to 10 day forecast, and expects that trend to continue through all of October.
Though the Climate Prediction Center doesn't predict specific temperatures, it does estimate with 80% certainty that the state will sit above normal in the next eight to 14 days.
Vipond noted that South Dakota's heat-induced drought will likely persist for much of the state, as data shows recent rains haven't done much to compensate for the summer's lack of precipitation.
However, there may be some relief in the long-term.
As the calendar turns to November, and a La Niña system begins to settle in over the mainland United States, temperatures are expected to trend more toward normal.
La Niña winters bring cooler Canadian air down to South Dakota, but doesn't have a major impact on snowfall. The system can last two years — last year's La Niña brought 30 inches of snowfall to the Mitchell area, while the 2010 system brought just under 50 inches.
Vipond predicted that because this winter will be the second consecutive La Niña, the state can expect to see above normal snowfall, but fewer inches than last year.
"We'll see if that comes to fruition," Vipond said skeptically. "It's possible we'll continue to see this drier trend continuing into the fall and winter seasons"
Meteorologists caution against taking winter weather predictions very seriously, as it's difficult to predict how a pattern elsewhere in the country could affect the locale more than a few days in advance.
"Inside 5 days is typically when we're most accurate, and in a 5-7 day period there's some accuracy, but it begins to fall off," NWS Sioux Falls meteorologist Andrew Kalin said. "I do know that any sort of long range forecast, whether it's (a National Weather Service forecast) or someone else's — I tend to take that with a grain of salt."
South Dakota is, after all, known for its wild and rapidly changing winter weather.
Data from the National Weather Service outlines the remarkable event in 1943 when temperatures in Spearfish rose from four below to 45 degrees in just two minutes. Later that day, temperatures dropped from 58 degrees back down to four below over the course of 27 minutes.
FiveThirtyEight, a data journalism organization owned by ABC News, proclaimed in 2014 that the Rapid City area was home to the nation's most unpredictable weather.
"I hate to use the word unpredictable," NWS Rapid City meteorologist Jon Chamberlain said with a laugh. "I like to use the words difficult to predict."
Chamberlain said that systems in his jurisdiction tend to develop right over their heads as their composition changes over the Rocky Mountains and Black Hills.
Luckily for residents in the Mitchell area, large areas of flatter land give weather radars and meteorologists plenty of time to catch and forecast incoming weather.
"Places to the east have a little bit more of that luxury," Chamberlain said.
Unfortunately for winter-weather lovers, the National Weather Service reports no instances of September snowfall in the Mitchell area since at least 2004.
Vipond expects the Climate Prediction Center to release updated seasonal outlooks with more accurate fall and winter predictions in October.
State Climatologist Laura Edwards did not return a phone call to discuss the historic climatology of South Dakota.