A cross-country winter storm system is expected to bring severe weather conditions to the South and Northeast.
Around 16 million people are at risk for a severe weather outbreak on Tuesday in the lower Mississippi and Tennessee River Valleys, which will include parts of Alabama, Arkansas, Louisiana, Mississippi and Tennessee.
Strong and long-track tornadoes will be possible along with baseball-size or larger hail and potentially destructive 75 mph winds.
A tornado watch was issued by the National Weather Service starting Tuesday afternoon for an area including northeast Louisiana, south Arkansas and central Mississippi.
The agency described the threat of tornadoes as "a particularly dangerous situation" and warned those in the area to be prepared.
Jackson, Mississippi, is in the center of the severe weather risk area, with other cities to watch being Memphis, Tennessee; New Orleans; Birmingham, Alabama; and Shreveport, Louisiana.
Given that sunsets are before 5 p.m. in most of the risk area, the majority of the dangerous storms will occur in the dark. This will compound the danger as nocturnal tornadoes are 2.5 times more likely to be fatal than daytime ones.
Flood watches are also in effect along parts of the east-central Gulf Coast, where storms could cause flash flooding through Wednesday morning.
The storm system will shift east on Wednesday, bringing strong thunderstorms, heavy rain and wind to the East Coast. Rain and wind will be the main weather drivers for the Mid-Atlantic to New England area, with strong storms possible from Georgia to northern Florida.
Atlanta; Mobile, Alabama; New Orleans; and Tallahassee, Florida, could all see strong storms, especially in the first half of the day.
It will likely be raining in New York City for the tree lighting in Rockefeller Center on Wednesday. There will also be gusty winds near 40 mph in the city, with temperatures forecast in the low 50s.
More than 1,990 flights traveling into or out of U.S. airports were delayed and 233 flights were canceled as of 1:45 p.m. ET on Tuesday, according to FlightAware.com. Most of those cancellations — 150 — were at Seattle-Tacoma International Airport, where Alaska Airlines canceled 90 flights because of winter weather expected in the area.
"Our flight operations will be impacted on Tuesday and throughout the week," the airline said in a statement. "Additional cancellations are possible as we assess the weather’s impact on our operation."
The northern side of this cross-country storm system will bring snow, which will affect the Upper Midwest.
As of Tuesday morning, snow was moving across parts of the central Rockies and northern Great Plains, into the Upper Midwest including parts of Iowa and Minnesota.
This area of snow is expected to continue east and move into places like the Minneapolis-St. Paul metro area Tuesday afternoon and early evening. Some snowfall rates of 1 to 2 inches per hour at times could arrive around evening rush hour.
A total of 3 to 6 inches of snow will be likely from southern Minnesota through the western Upper Peninsula of Michigan through Wednesday.