A moisture-packed storm system will march across the southern United States through the weekend into early next week. (Capital Weather Gang and Pivotal Weather)

El Niño winters like the one we are entering are known for their moisture-rich southern storms. Perhaps it is no huge surprise, then, that a major winter storm is shaping up across the southern United States, which could dump historic amounts of snow in the Southern Appalachians.

This developing winter storm, with Pacific origins, will affect a huge zone from the Southern Plains to the Mid-Atlantic. The storm kicks into gear Friday and lasts into early next week before departing.

As of early Thursday afternoon, winter storm watches were already up from eastern New Mexico through northwest Texas and across much of Oklahoma, then into the Arkansas/Missouri border region. Additional watches and warnings will be extended east in the days to come.

(National Weather Service)

On Friday, a low-pressure system begins to form over Texas and northern Mexico. Heavy rain spreads across Texas as snow and ice breaks out in areas along the northern portion of the storm system. Wintry precipitation is primarily expected from New Mexico through the Texas Panhandle and eventually into parts of Oklahoma heading into Saturday.

In the warm sector of this storm system, across Texas and eventually across the South, widespread rainfall totals of one to two inches are likely. A big chunk of East Texas may end up with as much as three to six inches of rain, including Houston, San Antonio and Austin. In this region, flood watches and river flood warnings are up because of the heavy rainfall anticipated over the coming days.

Any severe storm threat seems limited by the fact that the low-pressure center may track right along the northern Gulf Coast, thus limiting northward expansion of warm and humid air. If it ends up farther north than that, however, storms containing damaging winds and hail could develop in parts of the South, especially Saturday.

Precipitation totals (including melted ice and snow) through early week trace the path of the upcoming storm. (Capital Weather Gang and Pivotal Weather)

Although cold air with this system is somewhat limited, a swath of wintry precipitation stretching is expected along the storm’s north and northwest flank.

Snow totals are likely to first peak in the Southern Plains and Ozarks into Saturday, easing some through the Tennessee Valley before increasing again over the Southern Appalachians on Sunday.

Along with the snow threat, some significant icing is expected, especially in the Southern Plains. Widespread freezing rain accumulations of 0.10 inches to 0.25 inches are possible northwest Texas through southwest Oklahoma and into northwest Arkansas. Some locations may see up to half an inch of ice.

In Oklahoma City, where 3 to 6 inches of snow and glaze of ice are predicted Friday morning through Saturday evening, shoppers are clearing grocery store shelves of staples:

The storm’s most serious impact may target the Southern Appalachians. In western North Carolina and Southwest Virginia, a foot or more of snow may fall Saturday night through Sunday night. Heavy snow may also blanket portions of northwest South Carolina, eastern Tennessee and Kentucky and southwest West Virginia.

Some of the high terrain in western North Carolina may see upward of two feet of snow.

Snowfall forecast from the European weather model shows a broken swath from the Southern Rockies and Plains to the East Coast with the upcoming snowstorm. (weatherbell.com)

A number of population centers in western North Carolina and Southwest Virginia are likely to see substantial accumulation. Here are some select forecasts, which are subject to change as the storm track comes into focus:

  • Asheville: 12 to 24 inches
  • Blacksburg: 8 to 14 inches
  • Roanoke: 5 to 10 inches
  • Lynchburg: 3 to 6 inches

If a foot of snow falls in Asheville, it would mark the fifth-biggest storm on record. The total would need to best 18.2 inches to top the biggest snowstorm on record, from March 1993, which is a possibility.

Some questions remain about the intensity of snowfall in lower elevations to the east of the mountains, mostly Sunday. The best guess continues to be that even places like Greensboro, Charlotte, Raleigh and Richmond are likely to see at least several inches from this event, with amounts decreasing to the northeast within this zone.

How far north accumulating snowfall makes it in the Mid-Atlantic is up for much debate. The dividing line between accumulating snow and just flurries may set up in Central Virginia around Charlottesville — which could see several inches or just a dusting depending on the storm’s northward extent.

The Washington region seems unlikely to see a major snowfall, but it’s certainly possible that snowflakes will visit this region as well before the system wanders off into the Atlantic Ocean, especially if it shifts north.