Millions under winter weather alerts as storm pummels East Coast

A tornado watch has been issued for areas of South Florida, including Miami, until 3 p.m. ET.

Severe storms are firing on the southern side of the system bringing winter weather across the eastern US today.

These supercells and line of thunderstorms to follow will be capable of producing a couple of tornadoes and damaging wind gusts of up to 65 mph. This is the same line of storms that spawned tornado warned storms and caused damage along the Gulf Coast of Florida, near Fort Myers and Naples, earlier this morning.

Freezing rain is being reported in many locations across the North Carolina Piedmont this morning, according to the Storm Prediction Center (SPC).

Freezing rain is forecast to continue across portions of central North Carolina through the morning hours. Snow is currently falling across southeastern Virginia, this is forecast to gradually change over to freezing rain later this morning as well.

Here is a list of some preliminary freezing rain totals over the last 24 hours:

Further to the west, snow has been falling across the southern Appalachian mountains.

“Temperatures are currently below freezing across much of the southern Appalachian Mountains, where snow is being reported,” according to the SPC. “A few locations have exceeded one inch per hour snowfall rates.” Preliminary snowfall totals show 4 to 12 inches of snow has already fallen across some areas of the Southeast, with more snow still on the way.

Here are some preliminary snowfall totals over the last 24 hours:

A powerful winter storm has threatened parts of the eastern United States with crippling freezing rain, sleet and snow, as experts urge Americans to be prepared.

Make sure you've done the basics: Learn how to keep your pipes from freezing (for example, you can open cabinets in places like under sinks to let heat in or let faucets drip), test smoke alarms and carbon monoxide detectors, have extra batteries for radios and flashlights, charge electronics and consider specific needs of everyone in your household, like medication.

These kinds of storms — and their aftermath — can cut off heat, power or communication services. Because we don't yet know how severe the impacts will be and how long they will last, and amid supply chain problems that could further compound grocery shopping struggles this weekend, have at least three days' worth of food and water for everyone in your home, says Joann Sands, a clinical assistant professor in the School of Nursing at the University of Buffalo, who trains students in disaster and emergency preparedness.

Here are some other key tips to keep in mind:

Read more tips here.

Alongside the snowfall potential, strong winds from the east associated with the storm system could cause major coastal flooding of up to 3 feet above ground in some areas along the Northeast coast during high tide.

Parts of New York City, Long Island and some areas of Connecticut are under coastal flood warnings, forecasters said.

The timing of winds shifting from the east to the south will largely determine the severity of flooding, with moderate flooding potential if winds shift prior to high tide.

"Widespread moderate to locally major flooding of vulnerable areas is possible near the waterfront and shoreline, including roads, parking lots, parks, lawns, and homes and businesses with basements near the waterfront," the NWS in New York said Saturday.

Inundation could cause road closures and structural damage along the Atlantic coastline.

From the Mid-Atlantic through New England, the NWS said, "precipitation is forecast to begin as snow before changing over to ice/sleet and eventually rain with the approach of the storm center."

Some snow will fall in major metro areas, but a change to rain will hold down the accumulations. Washington could get 2-4 inches, while Philadelphia could get 1-2 inches. New York and Boston are expected to get about an inch each.

Heavier snow is expected elsewhere, with more than a foot expected in some locations.

Snowfall intensity in the region may be heavy enough to evade significant icing, but NWS Baltimore warned untreated surfaces may still lead to dangerous travel conditions where ice accumulates.

The majority of accumulating snowfall will occur Sunday afternoon through Monday morning.

Interior cities such as Charleston, Pittsburgh, Buffalo, Syracuse and Burlington, Vermont, will see the heaviest snow.

Prior to the snow event moving into the region, the Northeast will experience cold temperatures and dangerous wind chill, forecasters said.

There are at least 221,461 customers across the southeastern US that are without power as of 9 a.m. ET Sunday, according to PowerOutage.US.

These are the top areas by outages:

The latest winter storm to hit the East Coast is causing airlines to cancel flights by the thousands.  

US airlines have canceled more than 2,400 flights nationwide as of 8:45 a.m. ET Sunday, according to flight tracking site FlightAware. 

Airports such as Charlotte/Douglas International have been hit particularly hard, where 90 percent of all departures have been canceled. 

American Airlines, which operates out of its major Charlotte hub, has canceled 516 flights nationwide, or 18% of its total Sunday schedule.

American, Delta, Southwest, and United have all issued travel waivers allowing customers impacted by the storm to rebook flights free of charge.

There are 125,284 customers across the southeastern US that are without power as of 7:30aET Sunday, according to PowerOutage.US.

Here's a look at the top areas impacted by outages:

Over 80 million people are under winter weather alerts this morning across the eastern US, stretching from the South to New England, due to a major winter storm impacting the region.

The storm is currently impacting the Southeast states, bringing with it all facets of precipitation including rain, freezing rain, sleet, and snow. Much of the precipitation across the southern Appalachian has changed over to snow this morning and bands of heavy snow are likely to develop across this region.

Later this morning, the storm will track north into the Mid-Atlantic bringing with it heavy snow, ice, and rain. By Sunday night into Monday, the system will shift into the Northeast and New England where precipitation is likely to start as snow before changing to heavy rain over the coastal regions and heavy snow across inland areas.