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Posted at 11:53 AM ET, 11/28/2011

South braces for rare November snow

Northern Mississippi, Alabama and southwest Tennessee may see accumulation tonight


Chances of at least 1” of snow are higher (better than 60%) tonight across northwest Alabama and northeast Mississippi.
There’s something about the end of the month and rare early season snow this fall. In late October, parts of the mid-Atlantic and Northeast got pasted with historic snow amounts. Now, parts of the South may well see some unusual snowflakes to close out November.

A potent upper level low pressure system will dig into the mid-South tonight, with a pool of cold air sufficient to support snow in areas unaccustomed to it, especially at this time of the year.

Winter weather advisories have been posted as far south as Tuscaloosa and Birmingham, Alabama where a coating to sloppy inch is possible. Greater amounts are possible to the north around Memphis and Jackson, Tennessee where 1-3” is forecsat. The bullseye for snow amounts looks to concentrate in northeast Mississippi (including Tupelo) and southwest Tennessee, where 3” or more may fall and a winter storm watch has been posted.

Most of the frozen precipitation is expected to fall tonight. The farther south you go, the more likely the precipitation takes the form of rain with snow just mixing in.


Snowfall forecast for northern Mississippi and southwest Tennessee tonight. (National Weather Service)
Here’s how the National Weather Service office in Memphis describes the scenario:

A POWERFUL UPPER LEVEL LOW WILL MOVE SOUTH OF THE AREA TODAY AND TONIGHT. RAIN WILL REDEVELOP ACROSS THE AREA TODAY AND GRADUALLY MIX WITH AND CHANGE TO SNOW TONIGHT AS COLDER AIR MOVES OVER THE REGION. THE HEAVIEST SNOW SHOULD FALL ACROSS SOUTHERN WEST TENNESSEE AND NORTHEAST MISSISSIPPI LATER TONIGHT. PRECIPITATION WILL TAPER OFF TUESDAY MORNING AS THE SYSTEM LIFTS TO THE NORTHEAST.


Snowfall forecast for north central Alabama (National Weather Service)
And the National Weather Service in Birminghamoffers this synopsis:

A STRONG UPPER LEVEL DISTURBANCE WILL MOVE ACROSS NORTH ALABAMA TONIGHT...ALLOWING RAIN TO MIX WITH AND GRADUALLY CHANGE OVER TO SNOW FROM WEST TO EAST TONIGHT...ACROSS NORTH CENTRAL ALABAMA. THE GREATEST ACCUMULATIONS WILL BE IN NORTHWEST CENTRAL ALABAMA. PRECIPITATION WILL END TUESDAY MORNING.

The Original Weather Blog’s Rob White makes the good point that warm ground temperatures will limit accumulations:

The ground across the Deep South and mid-Mississippi Valley region is warm, which will have a significant impact on the accumulation of snow. In some areas, snow will fall at a rate that would normally accumulate very rapidly given cold ground conditions, but in this case, much of the snow will melt before beginning to accumulate.


“Bowling ball”-like upper low as simulated at an altitude of 18,000 feet Tuesday morning over central Tennessee.
Even with significant portions of the snow melting, White correctly notes that in this part of the country “just an inch of snow can seemingly bring commerce to a near halt in some areas.”

After blitzing the South, this upper level low will take a sharp turn to the north, riding up the spine of the Appalachians where snow may fall over the mountains of North Carolina and West Virginia Tuesday. By Tuesday night and Wednesday, the low will weaken, but produce some snows over western Pennsylvania into the eastern Great Lakes.

Additional reading: AlabamaWx.com

By  |  11:53 AM ET, 11/28/2011

Categories:  Latest, U.S. Weather

 
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