By Meteorologist Chris Dolce, CNN
(CNN) — More than half of the United States is about to face one of the most sprawling and menacing winter storms in years, one that threatens to deliver a potentially historic blow of snow and ice.
The long-lasting storm begins Friday, and by its end on Monday, will have dropped a foot or more of snow and destructive amounts of ice over its 1,500-mile path from Texas to the Northeast.
Major Northeast cities like New York and Philadelphia could get their most snow in at least four years, while major cities in the South deal with worrying amounts of ice.
More than 120 million people in two dozen states are under winter storm alerts — a number that’s expected to grow on Thursday.
Major travel disruption on roads and at airports is a given across the storm’s entire footprint, and widespread and potentially long-lasting power outages are also possible, particularly from its ice storm in the South.
Extreme and record-breaking cold will only worsen the storm and its impacts by causing snow and ice to accumulate faster on roads, making them harder to treat, and possibly leaving those that lose power shivering without heat for days.
Travel and power outage impacts could last into at least early next week for areas that see significant snow and ice totals.
Here’s the latest on the storm:
Track shifts, with huge implications
The track of this storm has become clearer and has shifted north over the past couple of days.
That shift has implicated more of the Midwest and Northeast with heavy snow while still delivering destructive ice to a large portion of the South.
Its track could still shift slightly, and that could impact the exact amounts of freezing rain, sleet and snow each area receives, with dramatic effects.
“Even small shifts could lead to large changes in local impacts,” the Weather Prediction Center said.
It all begins Friday in the Plains where the storm’s huge pool of moist air begins to clash with Arctic air. Through the weekend, the frigid temperatures will continue to feed the storm’s east and northeast expanding footprint, which covers more than two dozen states from the Plains to the South and Northeast.
The storm will finally exit New England by late Monday after spreading more snow and strong winds across the region and contributing to even more travel disruption.
Ice could knock out power to many
Damaging ice from freezing rain is the storm’s most serious threat.
Freezing rain causes ice to build up on surfaces, and its tremendous amount of added weight can bring down trees and power lines. The amount of ice in a worst-case scenario for this storm could cause many power outages, some that could be long-lasting. But power outages are expected even in the most likely scenario.
Portions of the South from northern and eastern Texas into the lower-Mississippi and Tennessee valleys, northern Georgia and parts of the Carolinas and Virginia are at greatest risk for significant icing and power outages based on the current forecast. This includes major cities such as Dallas-Fort Worth, Shreveport, Louisiana, Memphis, Tennessee, Huntsville, Alabama, and Charlotte, North Carolina.
Portions of the Atlanta metro could also see impactful ice, but that’s more uncertain due to a battle between cold air coming from the north and a surge of warmer air from the south.
Travel could be brought to a standstill across major cities even with smaller amounts of ice.
Heavy snow threat from Plains to East Coast
Heavy snow will pile up for a wide area to the north of the storm’s freezing rain zone.
Snow totals are likely to range from 6 to 12 inches for parts o