MegaBlock Takes Shape Over North America--translation-Snow, Ice, Cold

As we mentioned in early December the models were heading toward a very amplified, unusual state across the Globe, and we in the states are the primary beneficiaries.  A "Mega Blocking" signature over Greenland has formed and is responsible for the 12 to 18" snowfall in western NC last weekend, the clipper snows in the Piedmont of NC, and todays mountain snows, as well as now the Tennessee, Alabama and Georgia snow, not to  mention the incoming cold spell. Once again, our temperatures will struggle to hit 30 degrees on both Monday and Tuesday in Shelby and probably not to freezing in Charlotte as well. All the while , a blizzard is ongoing in the high mountain passes of NC and Tennessee, with snow accumulations as far south as Georgia, very near Atlanta and northern Alabama.
This cold air should lock in most of the week, and by Wednesday night, some overrunning moisture will work its way into our cold and very dry air. Snow and sleet should begin to break out over the western Carolinas around dawn Thursday and turn over to freezing rain.   By then, our ground will be frozen solid.  Accumulations are likely all over the Carolinas north of Columbia and west of the outer Banks.

Beyond this, the models are developing a Gulf low, and have been hinting at it for several days... another result of the extreme high latitude blocking going on. This blocking should force cold air to push much further south than normal over the next 2 weeks, and we have to monitor systems coming into California and taking the low road..normally, this type of setup is a snow and ice maker for the Carolinas and other parts of the Southeast. Theres still too much that can change on the storm track, we could either miss the system entirely to the south and east, or the system could fail to develop due to too much northern stream energy, or the system could travel directly up Interstate 85 in classic 1980's fashion, on to the Northeast as a major Nor'easter.  I'll post more on the threat if its still there, but for now the pattern looks to be repetetive and cold, with moisture arriving every few days, and snow reaching unusually far south.

central to eastern TN, northern Al, and GA, and the mountains of NC all get hit with some snow the next 2 days

Valid Dec 22 2010...the strong blocking continues.

Only time will tell if this pattern will become one that you'll be telling your Grandkids about someday, but overall , I'd say the upper level maps resemble the best maps of  "long gone Yore", such as the 1960's and late 1970s.  Blocks of this magnitude usually do strange things. Like, make it snow around here.