(CNN) -- The storm system that spawned a deadly spate of tornadoes in the Southeast has moved north, turning into a nor'easter.
It's slamming the coastal areas of New England with rain and strong winds, and could bring up to 10 inches of snow in inland areas.
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Meanwhile, the Southeast is picking up the pieces after dozens of tornadoes tore through the region over the weekend, killing 19 people -- 15 of them in Georgia and four in Mississippi. Both governors have declared states of emergency.
The tornadoes killed more people in one weekend than in all of last year, when 17 died across the country.
Overall, four weather-related deaths were also reported in California and one person died in Pennsylvania, increasing the nationwide total to 24 since the weekend.
Southeast digs out of devastation
Fifty tornadoes struck between Louisiana through south Florida, starting Thursday through Sunday, according to the National Weather Service estimates. The majority of them struck south Georgia.
The barreling twisters left people stunned and communities devastated.
"All you hear is people screaming, 'Help me, help me,' " said AJ Miley, a resident of the Sunshine Mobile Home Park in Georgia, according to CNN affiliate WSB-TV.
Devocheo Williams, also at the trailer park, said he saw people "tossed through the air," the TV station reported.
"All I saw was a little girl flown up and thrown in a ditch. Three seconds later, the trailer got picked up off the ground and landed on top of the mother and son," Williams said.
When the howling winds subsided, the landscape across the Southeast was dotted with overturned cars, debris and scores of damaged mobile homes.
At least six people were believed to be missing in Georgia, including a 2-year-old boy who was caught in the tornado in Dougherty County, officials said.
Chris Cohilas, the chairman of the Dougherty County Commission in southwestern Georgia, urged the Federal Emergency Management Agency to get "boots on the ground" to help the community. So far, he said, FEMA has not been responsive.
"To get caught up in the bureaucratic red tape at a time of this amount of human suffering is disgraceful," he said at a news conference on Monday.
In an email Monday, FEMA said the agency "is doing initial assessments of damages in Georgia today, including a flyover." FEMA will start federal and state preliminary damage assessments for individual and public assistance this week, the agency said.
FEMA representatives were also recently deployed to emergency centers in Alabama, Mississippi, Georgia and Florida to support the response, officials said.
A storm transforms into a nor'easter
The storm that hit the Southeast isn't quite done. It's now a nor'easter, triggering coastal flooding and wind advisories along the New England coast.
From New Jersey up to Maine, gusts could exceed 40 miles per hour with the strongest ones along Cape Cod. Isolated hurricane-force gusts of more than 75 mph were likely in parts of the Northeast, including Long Island, New York, and Cape Cod, Massachusetts, said Taylor Ward, CNN meteorologist.
In Philadelphia, a 60-year-old man in a car sales lot was struck and killed by a sign from the lot that the wind knocked off a wall shortly before 1 p.m. on Monday, Philadelphia police said. He died at the scene.
Besides strong winds, interior portions of Maine, New Hampshire, Vermont, New York and Pennsylvania could get three to six inches of snow, with higher amounts possible in some locations of up to nine inches.
On Monday, the weather caused flight delays at airports from Washington to New York and flooding at the New Jersey Transit Hoboken train station, which also flooded during Superstorm Sandy.
Train delays were reported in New York and New Jersey due to coastal storm conditions and downed power lines. The National Weather Service also issued a coastal flood warning for Southwest Suffolk County, New York, east of Manhattan, through Tuesday morning.
California governor declares state of emergency
In California, where a winter weather system has unleashed torrential rain and strong winds, Gov. Jerry Brown late Monday declared a state of emergency across 50 counties, including the cities of Los Angeles, San Diego, Sacramento and San Francisco. The move allows local officials to seek recovery money to repair damage from flash flooding, erosion, mudslides and debris flows.
Early estimates indicate losses in the tens of millions of dollars, according to the declaration.
Four deaths have been reported in California since the weekend: Two in San Diego County, one in Mendocino County and one in Los Angeles County. Two more people were missing off the coast of Pebble Beach, but the search was stopped because of deteriorating weather conditions, the US Coast Guard said Monday.
The weather system that has battered California has moved into the Rockies and the Plains where snow has begun to fall. Winter storm advisories are in effect as parts of Nebraska through the Dakotas brace for about six to 12 inches of snow.
But more rain is expected in northern parts of California through Tuesday evening. Strong winds are expected to remain through Tuesday night where waves along the southern California coastline could reach six to nine inches before it starts drying out midweek.
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