(CNN) - A winter storm tearing through the Southeast threatens to keep residents stuck at home with days of dangerous driving conditions, canceled flights and power outages.
Sunday will bring more than 12 inches of snow to the southern and central Appalachians, the National Weather Service said. Snowfall could total 12 to 20 inches over the Appalachians and into the Carolinas by Monday -- when the storm is expected to move off the coast, the agency said.
"Snowfall amounts in some locations will likely exceed a foot and result in several days of difficult or impossible travel, extended power outages, and downed trees," the agency said.
The storm has knocked out power for 216,578 customers in the southeastern United States. The bulk of the outages are in North Carolina, where 102,383 customers don't have power while in South Carolina it's 52,191. About 62,000 don't have power in both Alabama and Georgia.
The airport is the second-largest hub of American Airlines, which has "reduced its operations" because of the weather, the airport said.
American Airlines and its regional partners canceled 225 flights Saturday, 1,100 for Sunday and 300 for Monday, the airline said in a statement.
The Charlotte airport said it expects scattered cancellations through Monday morning, with the majority expected to be of small, regional planes.
The National Weather Service Greenville-Spartanburg measured 2.5 inches of snow as of 4:30 a.m. Sunday. A half an hour later, the Greenville County Emergency Management's Twitter page said that 14,189 customers were without power.
Meanwhile, in North Carolina, authorities declared a statewide emergency Friday ahead of the storm.
"Snow may be beautiful but it can also be treacherous and I urge North Carolinians to take this storm seriously and get ready for it now," Gov. Roy Cooper said in a statement.
Many churches in the Charlotte area have preemptively canceled Sunday services, CNN affiliate WSOC reported, and the city of Charlotte is prepping emergency shelters. Grocery store shelves have been cleared of bread, milk and other staples.
"This storm comes at a time of year when North Carolinians are usually hearing carols about snow, not actually seeing it. But this time, the real thing is headed our way and North Carolina is getting prepared," Cooper, the North Carolina governor, said, according to WSOC in Charlotte. "A winter storm's not a Christmas carol snow. It's serious, and you need to take steps now to get your family ready."
Rain, snow, ice and flooding
Before moving east, the moisture-heavy storm walloped Texas, causing downpours and flash flooding along the southern edge of the state and snow and ice in the north. As the moisture moves eastward, it is colliding with a high-pressure system over the Ohio Valley that is funneling cold air into the region.
"It's kind of a big deal," CNN meteorologist Allison Chinchar said. "It's December. This is not the time of year that they would typically get this stuff."
Houston experienced flooding after 4 to 6 inches of rain fell on Friday night into Saturday morning. Pouring rain inundated roads all over the Houston area. Many drivers found themselves stuck.
After the heavy rain in Lubbock, Texas, many community activities were disrupted. The city holiday parade was postponed and Texas Tech rescheduled all Saturday final exams until Sunday, CNN affiliate KCBD reported.
Lubbock also saw 10 inches of snow -- 2 inches more than the city usually gets in a whole year.
"They crushed their yearly average in 24 hours," CNN meteorologist Ivan Cabrera said.
The Lubbock Police Department tweeted late Saturday that black ice and freezing fog were beginning to form on areas of Interstate 27. Police said they were "working about 20 wrecks due to these dangerous conditions."
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