More normal winter weather predicted for Corn Belt

“Snow this time of year when there wasn’t snow this time last year is very encouraging to me, and you should be encouraged too,” said Eric Apel, agricultural meteorologist for Mobile Weather Team Inc., a weather-forecasting services company based in Washington, Ill.

Apel gave his outlook for the winter and spring going into 2013. The snow that he was referring to isn’t the product of the most recent winter weather over the Midwest.

Apel said that colder, wintry weather in Canada could mean some relief for the parched fields of the U.S. Midwest.

“Up in Canada, we’re talking about very, very cold air starting to build. Much of Canada is covered in snow. That’s not a huge surprise for Canada, but compared to last year, much more snow cover in Canada and more snow cover. Snow cover means colder air collects up in Canada. That cold air is going to move down into the Midwest and will benefit us,” said Apel, who spoke in Sterling at the Northwestern Illinois Farm Show, sponsored by the Whiteside County Farm Bureau, the Sauk Valley Area Chamber of Commerce and the Sterling Park District.

Apel outlined differences between conditions this time last year, leading into a dry, warm winter, unusually warm spring and then summer drought, and this year. He noted that conditions in Canada do affect weather in the Midwest, Great Plains and northern Plains.

Even though temperatures going into December were warmer than normal, Apel said he doesn’t expect that to herald another warm winter.

“I don’t think it’s setting up for another winter of 2011-’12. Surface temperatures forecast for the week of Dec. 10 are 50 below to 60 below up in Canada. This time last year, it was maybe negative 20 or negative 30. We’re talking about considerably colder temperatures. That cold air doesn’t want to stay in place. Once it builds up, it’s got to go somewhere and it’s going to go into the areas where warmer temperatures are at,” he said.

Apel said the cold air also means good news for the moisture already in the soil from rains earlier in the fall.

“Colder weather means less evaporation, so the soil moisture we’ve built up through the fall is going to stick around and not evaporate like it did last winter,” he said.

Apel said that water temperatures in the tropical Pacific Ocean — the harbingers of the El Niño and La Niña weather-creating systems — are neutral, which means forecasters have to look at other factors to determine what weather may do.

“It’s going to stay in the neutral range, so there’s something else that will determine what our weather patterns will be,” he explained.

Apel said three weather patterns, the Arctic Oscillation or AO, the Pacific North American Oscillation or PNAO and the NAO or North Atlantic Oscillation are looked at to determine what weather could do for the Midwest.

However, he noted that the patterns can change drastically, which means forecasters can’t give a firm forecast for more than two weeks forward.

To get a more accurate look for the longer term, they use the stratospheric temperatures, the temperatures and conditions in the very upper layers of the Earth’s atmosphere. Apel combines those temperatures with the Arctic Oscillation, the circulation of weather over the Arctic Circle above 66 degrees north latitude.

“The strength of the polar vortex determines how much of the cold air in the north can make it down into the Midwest,” he said.

Apel said a combination of stratospheric warming and a negative Arctic Oscillation means good news for Midwest farmers hoping for snow and cold air.

“Forecast temperatures over the next 16 days, sudden stratospheric warming means Arctic Oscillation is going to go negative, that’s good for us. I believe this will occur. We’ll have a negative oscillation, cold air and a more beneficial winter,” he said.

Apel said the same phenomenon that contributed to the drought — that of dry conditions at ground level feeding the lack of storms, also can benefit with moisture.

“I think we’ll have above-average snowfall this year. When the snow falls on the ground, it keeps things from evaporating out of the ground. It evaporates moisture into the atmosphere. Even though there’s not a lot of moisture in those systems from the north, that snow does evaporate moisture into the atmosphere so when we do get systems, it will start to build a positive feedback so those systems will produce more snow,” he said.

Apel said that Midwesterners also can break out the winter gear since temperatures will be colder.

“I expect colder-than-normal temperatures overall. Will we get some warm surges? Sure. It happens all the time in a normal year, but they won’t stick around. It will be colder overall when you look at the whole winter. I believe we’ll look back and see that the temperature average was colder than what we normally would see, and that’s a 30-year average normal,” he said.

As far as the spring goes, heading into planting season, Apel said farmers likely won’t be heading to the fields in early March in 2013.

“I think the patterns will stick around at least through early spring. I think what’s going to happen is that in the early spring, we’re going to have a good chance for March snowfall, which was just unheard of this past year,” said Apel, who said he couldn’t rule out late frosts as the jetstream shifts on its move back to the north.

“While that’s happening, we’re going to get some large temperature swings. I think, unfortunately, that will mean some late April frosts. Maybe even a week or two later than what we would normally see as that last frost date for the spring. It’s very unlikely that we see another March like last year. Same for April and May.”

Apel started his presentation by outlining the factors that contributed to the widespread U.S. drought in the spring and summer of 2012.

Apel said that the warm and dry conditions that began in March started the literal march toward drought. Rain-producing systems moved toward the Midwest, but then hit high pressure, which directed them around the eastern Corn Belt.

“That was a persistent pattern through the month of March. You get some moisture deficit. You get a little bit of heat. That high pressure ridge builds in, and it looks like it’s going to move in. It hangs around for the month,” he said.

He said the lack of soil moisture fed into the lack of storms.

“Dry weather feeds dry weather. The further we went without getting any good rains, the worse it got because every system just got drier and drier. When there’s no rain, it just feeds into itself. It creates a feedback loop. With a lack of soil moisture, rain was harder to come by,” he said.

Apel noted that at the start of December, while much of the state still was short of moisture, conditions were improving.

“We’re much better off. We’re still short on moisture, just not quite as bad ad we were,” he said. “We should see some improvement going forward.”

Mobile Weather Team offers an agricultural weather-forecasting subscription service for farming and other weather-dependent industries through its website at www.mobileweather.com.