Potentially Major Winter Storm to Bring Snow, Ice to Gulf Coast, Georgia and Carolinas

By: By Nick Wiltgen

Published: January 26,2014

 

 

 

 

 

We are watching for the potential for a potentially major winter storm to affect a long swath of the Deep South this week – including places better known for their beaches, balmy breezes and hurricanes. This will include some of the areas affected by Winter Storm Kronos just last week – but it includes millions of people farther east as well.

Storm Ingredients

The threat stems from the combination of a bitterly cold arctic air mass plunging southward behind a sharp cold front, while moisture streams northward from the Gulf Coast. As the moisture crosses into the cold air behind the front, a swath of frozen and freezing precipitation is likely to break out.
(FORECAST: Arctic Blast This Week)
Already, the National Weather Service in Charleston, S.C. has issued winter storm watches for the South Carolina Lowcountry and parts of southeast Georgia, including Charleston and Savannah, Ga. It's the first winter storm watch issued for those two cities since Feb. 11, 2010.
These are just part of a swath of winter storm watches stretching from southeast North Carolina to southeast Texas. In fact, the National Weather Service has issued a winter storm watch for Houston for the second time in just five days.
(MAP: Clickable Winter Weather Alerts)
Let's step through the forecast and get into the details and uncertainties.

Long Stretch of Ice and Snow

Tuesday: Western Gulf Coast

Tuesday: Eastern Gulf, Carolinas

Tuesday Night

Wednesday Snow Potential

The latest blast of arctic air, already bursting south into the Midwest, will reach the Deep South Monday night. Temperatures should be at or below freezing by Tuesday morning along the Gulf Coast from Houston to Pensacola, Fla., as well as portions of the Carolina coast.
As Tuesday wears on, a broad zone of rising air will develop across the entire Gulf Coast (except for southwest Florida) and the Atlantic Coast of the Southeast, along and behind the arctic cold front. This will allow an elongated area of precipitation to develop from South Texas all the way to the Carolinas.
Since much of this precipitation will be falling over areas where near-ground temperatures will hover below freezing, the result will be a mess of wintry precipitation.
Exactly which form the precipitation takes will depend on temperatures several thousand feet aloft. In some areas, the entire atmosphere will be below freezing, and those areas will be vulnerable to snow. In areas closer to the Gulf Coast, there is likely to be a layer of above-freezing air above the ground, setting the stage for sleet and/or freezing rain.
But model projections disagree on exactly how far south the all-snow scenario will get – not just Tuesday, but for the duration of the storm. For that matter, it is not entirely clear just how far north (inland) the wintry precipitation will fall. More on that later.
By Tuesday night, as an upper-air disturbance moves into the western Gulf of Mexico and a separate area of weak low pressure develops off the Carolina coast, we expect areas of heavier precipitation to break out from the central Gulf Coast to the Carolinas. This will bring the potential for heavier snowfall and/or ice accumulation in these areas, again depending on the precise vertical temperature profile in the atmosphere.
Precipitation should end west of the Florida Panhandle by Wednesday morning, but Wednesday will see precipitation lingering from central and northern Florida to southeast Virginia. While wintry precipitation will probably stay north of the Florida/Georgia border (though not by far), leaving the Florida Peninsula just wet, there could be additional snow and ice accumulations from south Georgia northeastward.

Where, How Much, and How Bad?

Forecasting snow and ice accumulations in the Deep South is, as you might expect, always tricky.
There are two main factors contributing to the uncertainty this time:

• How far south will the entire atmosphere be below freezing, allowing for pure snow?
• How far inland will the precipitation fall?

The Sunday daytime runs of the European and American forecast models differ on the first question, with the European model favoring snow all the way to the coastal Carolinas and much of the Gulf Coast. The main American models, on the other hand, tend to keep a zone of warmer air aloft over the Gulf Coast and the Atlantic Coast of the Carolinas, favoring more freezing rain and sleet in those areas. Farther inland, though, this should be a predominantly snow event for interior sections of south-central and southeast Texas, Louisiana, Mississippi, Alabama, Georgia, and the Carolinas.
As for the second question, it currently appears that the wintry precipitation will mainly stay south of the Interstate 20 corridor from Dallas-Fort Worth to Atlanta, missing those cities and points in between. However, the I-20 corridor from Shreveport to Atlanta isn't totally off the table just yet.
(FORECAST: New Orleans | Biloxi, Miss. | Mobile, Ala.)
Farther east, it appears that the southeast half of Georgia, the eastern half of South Carolina and the eastern one-third of North Carolina is most at risk for accumulating snow and ice. Again, however, there is a possibility that the features of this storm will pull the precipitation a bit farther inland, which would implicate parts of Upstate South Carolina and central North Carolina as well.
(FORECAST: Augusta, Ga. | Columbia, S.C. | Raleigh, N.C.)
As with any Deep South winter storm, additional complicating factors include warm ground (temperatures in the 60s and 70s Monday) as well as the amount of precipitation that falls and what form it takes.
This does appear to be a fairly moisture-loaded system for areas along the coasts, so snow and ice accumulations could be quite heavy, particularly from coastal Georgia to the eastern Carolinas. If the precipitation falls as all snow, amounts in excess of 6 inches are within reach from southeast Alabama through south Georgia and into the eastern Carolinas.
If, instead, the heaviest precipitation falls as freezing rain, there could be damaging ice accumulations in those areas, and potentially farther west toward Louisiana, leading to falling limbs, trees, and significant power outages.
It's also possible that there will be a significant swath of sleet with this storm, which would limit the damaging effect of freezing rain but also cut into snowfall accumulation.

Prepare Now

This storm has the potential to disrupt travel and power. There is uncertainty on the amount of wintry precipitation that will fall. However, if ice accumulations reach the higher end of the range of possibilities, there could be widespread power outages and road blockages due to falling trees and tree limbs, not to mention the weight of ice on power lines themselves.
Travel could become dangerous or even impossible in some areas due to heavy buildup of ice and/or snow.
Our WeatherReady winter weather safety section has more tips on how to prepare for the possibility of dangerous driving conditions and extended power outages.
(MORE: WeatherReady Winter Safety & Preparedness)
Stay with The Weather Channel and weather.com for the latest on this developing winter weather situation.
MORE: Winter Storm Iago Hits the Deep South, Jan. 17-18, 2013

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Hartselle, Alabama

Heavy snow falls in Hartselle, Ala., causing many traffic problems and some fun for children Thursday, Jan. 17, 2013. Motorist James Burton stands in front of his car stranded on US Highway 31 on Hartselle Mountain after the stretch of highway became to slick for many motorists to get up the hill. (AP Photo/The Decatur Daily, Gary Cosby Jr.)