Deep South Winter Storm

While we sit in the frigid cold and watch what's left of the snow sublimate away into the dry air, us weather nerds have been looking ahead to the next storm. In the Mid Atlantic, there does not seem to be any credible potential for snow within the next week although it will be quite cold. A "warm up" to the mid 30's is possible tomorrow morning before plummeting for the rest of the week. temperatures cold rise again next weekend. Since we will be in the heart of the cold high pressure, there will be no precip. The low pressure systems travel around the high. As a result storms will be shunted south around the high, setting up the south for frozen precip.

The setup seems good for a storm. Southern energy from the Pacific crosses over into the gulf while energy dives down from the north, and a surface low forms in the gulf. With the bitterly cold air in place, precipitation has a large chance of being frozen. The proximity to the warm gulf provides for plenty of moisture and as a result plenty of precip, much of it frozen, falls and accumulates.

Although they vary significantly with details, the models have been remarkably consistent with bringing some form of heavy frozen precip (snow, sleet, freezing rain) to from the gulf coast to Virginia beach with a the heaviest swath over the coastal Carolinas. There, snow accumulations over 6 inches are possible. Farther south, 1-2 inches of snow is possible with ice accumulations as the cold air undercuts the warm air. Areas directly on the coast will have the least frozen precip because of the moderating effect of the ocean. Ice accumulations of .25 inches is possible. The heavy wet snow and ice will weigh down the power lines and trees while the cold temperatures and poorly insulated houses will create a extremely high demand for electricity, stressing the electrical grid. The frozen precip will cause major traffic issues and could shut down the south.

Here are the 3 main models we use to make forecasts. Be aware these snowfall maps are using 10:1 ratios and the ratios will be likely much lower, around 6:1. In addition, the cold air closer to the coast will be quite shallow leading to sleet and freezing rain, cutting down on snow totals and being models, the scenarios being portrayed by the models will not be what will actually happen.

12z NAM


12z GFS


12z ECMWF

Being in a subtropical climate, the areas expected to be impacted by this storm is not prepared for any winter precip, let alone a full blown winter storm. As a result, the criteria for a winter storm warning is lower than it is farther north. Here are the NWS offices's takes on the upcoming storm.

 NWS Houston

...WINTER STORM WATCH FOR TUESDAY...

.AN ARCTIC AIRMASS WILL SETTLE OVER THE AREA LATE MONDAY DROPPING
TEMPERATURES TO AROUND FREEZING TO WELL BELOW FREEZING TUESDAY
MORNING. AN UPPER LEVEL DISTURBANCE WILL MOVE TOWARD THE REGION
FROM THE SOUTHWEST HELPING TO INITIATE THE DEVELOPMENT OF
SNOW...FREEZING RAIN...AND SLEET. THIS WINTER PRECIPITATION SHOULD
CONTINUE THROUGHOUT THE DAY AND TAPER OFF FROM NORTHWEST TO
SOUTHEAST BY EVENING ALONG THE COAST. SIGNIFICANT ICING IS LIKELY
ACROSS THE REGION. SNOW FALL ACCUMULATIONS OF 1 TO 2 INCHES SHOULD
BE COMMON OVER THE NORTHERN HALF OF SOUTHEAST TEXAS WITH ISOLATED
HEAVIER AMOUNTS. TEMPERATURES SHOULD BOTTOM OUT WEDNESDAY MORNING
IN THE 20-25 DEGREE RANGE FROM INTERSTATE 10 NORTHWARD.

NWS New Orleans



THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A WINTER
STORM WATCH...WHICH IS IN EFFECT FROM TUESDAY MORNING THROUGH
LATE TUESDAY NIGHT.

* TIMING...A WINTRY MIX OF PRECIPITATION COULD BEGIN AS EARLY AS
  TUESDAY MORNING...WITH THE HEAVIEST PRECIPITATION EXPECTED
  TUESDAY AFTERNOON AND EVENING.

* IMPACTS...SNOW AMOUNTS IN EXCESS OF TWO INCHES AND SLEET AND
  FREEZING RAIN ACCUMULATIONS OF A QUARTER INCH OR MORE ARE
  POSSIBLE ACROSS THE ENTIRE AREA. TRAVEL CONDITIONS ARE EXPECTED
  TO BECOME DIFFICULT DUE TO ICY ROADS AND BRIDGES DURING THE DAY
  ON TUESDAY. IN AREAS WHERE SIGNIFICANT FREEZING RAIN
  OCCURS...SPORADIC POWER OUTAGES ARE POSSIBLE. THE HIGHEST
  POTENTIAL FOR FREEZING RAIN WILL BE ACROSS SOUTHEAST LOUISIANA
  SOUTH OF LAKE PONTCHARTRAIN INCLUDING THE CITY OF NEW ORLEANS.

NWS Wilmington 

 

...WINTER STORM WATCH IN EFFECT FROM TUESDAY AFTERNOON THROUGH
WEDNESDAY AFTERNOON...

THE NATIONAL WEATHER SERVICE IN WILMINGTON HAS ISSUED A WINTER
STORM WATCH...WHICH IS IN EFFECT FROM TUESDAY AFTERNOON THROUGH
WEDNESDAY AFTERNOON.

* LOCATIONS...SOUTHEAST NORTH CAROLINA AND NORTHEAST SOUTH
  CAROLINA.

* HAZARD TYPES...SNOW AND SLEET. POCKETS OF FREEZING RAIN ARE
  POSSIBLE.

* ACCUMULATIONS...THE RISK FOR SIGNIFICANT ACCUMULATIONS OF SNOW
  AND SLEET IS INCREASING. SNOW AMOUNTS MAY EXCEED 3 INCHES.