(Radio Iowa) – Some forecasters are raising the possibility of heavy snowfall in Iowa next week, with an especially strong winter wallop for northern Iowa, potentially impacting Thanksgiving travel, but other forecasters are holding off on making a call until later. Meteorologist Dylan Dodson, at the National Weather Service, says Thanksgiving is still a bit too far away to make an accurate prediction.

“Our forecast only goes out seven days,” Dodson says. “Generally, beyond seven days, it gets a little bit more difficult to forecast, because the further you get from the current time, those possibilities start to expand. It’s kind of like that butterfly effect. As you get out further, those chances start to become less certain.” Computer forecasting models from the National Weather Service are -not- projecting anything that would make snowfall for Iowa likely in the six-to-ten day forecast.

“At least through the beginning of next week, we’re looking at above-normal temperatures — normal for this time of year is right around the upper 40s to 50 degrees for the Des Moines area — and then kind of cooler in the north, warmer in the south,” Dodson says, “so, leaning above-normal for temperatures and then also leaning slightly above-normal for precipitation.” With the agency’s eight to 14-day forecast, he says temperatures are trending to near-normal with slightly above-normal precipitation. But is a ten-inch snowfall before Thanksgiving likely?

“I wouldn’t say it’s unlikely at this point. I wouldn’t say it’s likely either,” Dodson says. “It’s just difficult to gauge that at the moment. We’ll be watching the forecast once it starts to get into the seven-day especially. We’ll definitely be starting to look at where the patterns are, but at the moment, there’s too much uncertainty to really hang your hat on anything.”

According to National Weather Service data from 1981 to 2010, the normal date for the first one-inch snowfall in northwest Iowa is between November 10th and 17th, with the first inch of snow typically falling much later in southeastern Iowa, between December 12th and the 19th.