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    Joe Lundberg

    Suddenly It Looks a Lot Like Winter

    12/27/2012, 6:27:47 AM

    Thursday, 11:30 A.M.

    The powerful storm that generated severe thunderstorms across the South on Christmas Day, and a few more yesterday in the Carolinas, has also had a snowy history. From snow in the Rockies on Christmas Eve, to snow and ice in Oklahoma and Texas Christmas Day, to heavy snow Wednesday in Indiana and Ohio into Pennsylvania, and the snow that's still falling in northern New England, this storm has clearly stamped "winter" on the national scene. The latest snow cover analysis:

    You would never know looking at that map most places east of the Rockies have been much warmer than normal in December. In fact, the month had been warmer than it was last December, believe it or not!

    That all has changed. And more snow is on the horizon, along with more cold.

    The next storm will begin to take shape tonight and tomorrow over East Texas and the lower Mississippi Valley. As storms go, it will not be as potent as the one now moving away from the Northeast, nor will it have as large of a contrast from the warm side of the storm to its cold side. That also means little severe weather, if any, and overall a lot less moisture associated with it.

    Eventually low pressure will emerge off the Virginia Capes early Saturday night, if not farther south. The track is somewhat critical, as it could determine where the rain-snow line might end up, and how much snow might fall north of that line. There will effectively be two pieces to the storm, with a leading piece driving the low toward the East Coast, and a trailing piece generating an area of clouds and snow on its own a little farther to the north and northwest as the inverted surface trough slides through the Ohio Valley and across the northern mid-Atlantic region.

    The American models, for what its worth, have been electing to keep these two features apart long enough to limit how much snow can fall in the cold air north of the track of the surface low. They are also farther south with the track of the surface low, all of which means limited snow amounts for places like Philadelphia, New York and Boston, and even less across interior New England. Here's the 12z Thursday GFS 48-QPF forecast from Friday evening through Sunday evening:

    That essentially means less than three inches of snow for most of the I-95 corridor, with the best pace to be for snow back in the central Appalachians of West Virginia.

    On the other hand, the European and Canadian models at last check are more impressed with the storm, and bring more moisture through the mid-Atlantic into southern and eastern New England. I'm not sure which idea is right, but given their superior performance with the event now winding down, I must admit I'm leaning toward that option. More on that tomorrow.

    Regardless, we should expand the snow cover even more between now and the end of the weekend, and that makes it easier to get and stay cold, all other things being equal. And as if on cue, there appears to be a couple of attacks of some pretty cold air in the low levels of the atmosphere aimed at the Midwest and Great Lakes into the Northeast late this weekend and into next week. While the arctic will be drained entering the new year, that cold air has to go somewhere, and look at the latest GFS ensemble projections of temperature anomalies for next Wednesday:

    My gut feeling is that this is overdone, and there is some sort of feedback going on in the model thanks to the deep snow pack that is now in place. I still think it'll be cold, but that may be overdone. Still, all things considered, and despite calls in the past week or so of "winter" cancel, it's suddenly starting to look (and feel) a lot like winter in much of the country.

    The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com


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    Joe Lundberg