密歇根新闻广播 寒冷的冬季降至（在线收听）

It's that time of year: the days are getting shorter, the temperature is dropping, and Michiganders are beginning to (reluctantly) accept that winter is near.

The last two winters have been overall warmer on average, but with multiple periods of polar vortex, or extremely frigid temperatures.

So what does this upcoming winter have in store? Snowy and warm, with a chance of polar vortex.

The National Oceanic and Atmospheric Association (NOAA) released their annual winter forecast Thursday.

It looks like we have a better chance of a harsh winter than we do for a typical or even mild winter, says NOAA meteorologist Rich Pollman.

NOAA forecasts predict above-normal precipitation throughout the Great Lakes region.

Every winter has snow, says Pollman. This winter looks like we're going to have at least average snow, with the potential for a little bit more than that. So plan on a typical winter, and we won't be surprised by anything.

Meteorologist Jeff Masters is the co-founder of Weather Underground. He says predicting long-term winter weather is especially difficult during the neutral phase of the El Nino.

Masters says, When there is an ongoing El Ni?o or La Ni?a event going on — which cause large-scale warming or cooling of the waters of the Eastern Pacific Ocean, thus affecting long-term climate patterns — we can make more confident predictions on what the winter weather will be like.

Instead, other factors are used to predict winter weather conditions, such as the sunspot cycle.

We are currently at a deep minimum in the sunspot cycle, says Masters, and we've seen in the past that such occurrences tend to promote what we call blocking events in January and February, areas of high pressure that set up over Greenland, blocking the jet stream flow, and forcing cold air to funnel southwards into the Midwest and Eastern U.S. in the notorious polar vortex events with extreme cold.

Another important factor in winter weather is the Arctic Oscillation (AO), which is the atmospheric circulation pattern around the Arctic. But the AO doesn't help scientists with long-term predictions.

The Arctic Oscillation can only be forecasted about two to four weeks in advance," Pollman says. "So how that sets up during our winter months, we might be able to give a two week heads-up notice, maybe a four week heads-up notice when that polar vortex is gonna be swinging through.

And with frost and some snow already in the forecast, it might be wise to dig out your winter gear now.