The coldest air of the season is finally moving south out of Canada; check out the map that I included of 6 PM/Friday temperatures across the northern part of the country. Temperatures are near zero right now through the Dakotas, Minnesota, and into the northern Great Lakes with a snowstorm brewing for the Northeast. In fact, it'll be the first real snowfall since the freak Halloween storm that buried parts of the Northeast in several feet of snow! The fact that we're talking about cold and snow now across the northern part of the country is certainly a shift from the last several weeks.

What's changed? We meteorologists look at things called "indexes" to get a feel for the overall global weather pattern. Two, in particular, are important to just how cold a winter is in the United States. One, the North Atlantic Oscillation or NAO, has not changed much since winter's start. It's still in a positive phase which means any given cold snap does not last very long. Intrusions of cold air into the southeast are brief and not, really, very cold. This doesn't look to change much over the coming weeks. The index that has changed, though, is something known as the Arctic Oscillation. Over the last several months, this index has been positive -- meaning cold air is locked up in the far northern latitudes. Over the last several days, though, the index has flipped and become more neutral, indicating the approach of much colder air farther south in the northern hemisphere. The index is not negative, though, which is -- in part -- keeping the coldest of air bottled up along the US/Canada border.

So we know it's cold across the north, but what about here in Florida? As winter reminds folks in the North-Central and Northeast parts of the country that it's still January, we're actually going to flash back to the warmest weather we've seen since Christmas Day this weekend! Highs will climb to near 80 degrees both Saturday and Sunday as a ridge of high pressure dominates across the southeast. The weekend will feature lots of sunshine Saturday with only a few more clouds Sunday. It's the kind of weather you want to brag about to your friends up north!

Have a great weekend.

Brian Monahan