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    Surges of Arctic Air to Continue Into the New Year

    12/26/2013, 6:35:05 AM

    Thursday, 11:30 a.m.

    Spring is a long way away. I mean a LONG way away. There was a nice taste of it last weekend in the eastern half of the country, and it will be relatively mild again this weekend, but don't be fooled. There's a lot of winter ahead of us, and if you are one who enjoys those bitterly cold days and frigid nights, well you're going to get your wish.

    It's not exactly tropical this morning from the mid-Atlantic to the Northeast, and there's been some snow across Pennsylvania and New York state into New Jersey associated with an upper-level trough of low pressure progressing through the region. There won't be a lot to show for it in much of New England this afternoon, but there can be some snow in eastern Massachusetts and Maine for a while this afternoon and early tonight.

    With the very cold air coming across the open lakes, there will also be some flurries and a few bands of heavier lake-effect snow downwind of the lakes this afternoon and tonight before fading tomorrow morning.

    Then there will be a break in the cold. Temperatures tonight will rise in the Dakotas, rather than fall, as the milder air comes charging across the northern Plains toward the Upper Midwest. Look at the 12z Dec. 26 NAM surface forecast for tomorrow morning:

    With the surface low moving across southern sections of Alberta and Saskatchewan into southern Manitoba, hauling the warmth out of the northern Rockies. As we crank the clock ahead another 24 hours to Saturday morning, that same low will be passing east of James Bay. Then, with surface high pressure over Virginia and North Carolina, the southwest flow will carry milder air across the Midwest and into the Great Lakes and Ohio Valley, even into the mid-Atlantic states. Here's the NAM surface forecast for Saturday morning:

    Then two things will happen. One will be the formation of low pressure in the Gulf of Mexico Saturday. That storm will cross the Southeast Saturday night into Sunday morning, then move off the mid-Atlantic coast by Sunday evening. You would think with the arctic air we've suffered through of late, that there would be widespread snow north and west of the track of the storm. However, the air of the storm will be milder, and most of this storm will end up being rain.

    That said, there is the danger that more robust precipitation rates Sunday afternoon and into Sunday night back in and near the mountains may be enough to cool the column to the point at which rain would change to heavy, wet snow before ending Sunday night. That's most likely from the higher ground of West Virginia northeastward toward central Pennsylvania and the Poconos, then over the northwest hills of Connecticut and the Berkshires up into Maine. More on that tomorrow.

    The other thing that will happen is another arctic press will barrel into the northern Plains, then turn southeastward across the Mississippi Valley into the Midwest, then the Great Lakes and the Ohio Valley as the weekend progresses. For instance, the high for Saturday in eastern North Dakota is probably at or before daybreak in the teens, perhaps as high as 20 in some places. By day's end, though, it will be extraordinarily windy and sharply colder with temperatures dropping below zero! Here's the 850mb temperature forecast for Sunday evening:


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


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