This Is Not Your Typical Winter Storm Coming

In meteorologist-speak, the winter storm now shaping up to wallop a good chunk of the US this weekend will likely be "unusually impactful." That's the term used by Alex Lamers of the Weather Prediction Center to the New York Times, and it suggests things might get particularly nasty for a combination of reasons. "It's not something you see every winter," says Lamers. It's "likely to affect about half the US population with accumulating ice, sleet, or snow." Another problem: The weather system is bringing along a surge of bitter cold temperatures, meaning whatever does fall won't melt for awhile.

• The AP estimates that 100 million Americans are currently under some kind of winter weather watch, warning, or advisory in at least 19 states from New Mexico to the Carolinas. Weather.com figures 180 million Americans will likely be affected in some fashion.
• The complex system is changing quickly, meaning local forecasts are also changing on the fly. Small shifts in temperature and track could dramatically change outcomes in places like Nashville—currently straddling the line between relatively routine snow and severe icing—and in Texas, where a sequence of freezing rain, sleet, and snow could create "cobblestone ice" (with a thick base layer) of the type that crippled the region in 2013.
• The storm is expected to roll out of the southern Rockies on Friday, dropping snow on parts of New Mexico and Colorado before spreading into Kansas, Oklahoma, and Texas. By Saturday, it broadens over Texas, Arkansas, and Tennessee with freezing rain, sleet, and snow, while snow advances across the Midwest and precipitation reaches Georgia and the Carolinas by evening. On Sunday, the system pushes into the Mid-Atlantic and Northeast, where it may strengthen. On Monday morning, temperatures will be so cold in some areas, that anything wet will freeze.