Charlotte could get 12 inches of snow. Added threat could make driving treacherous.

Charlotte and counties surrounding Mecklenburg could see up to a foot of snow and sleet this weekend, breaking the city’s all-time record for December set in 1882, according to the National Weather Service.

The latest maximum snowfall predicted from Saturday night through Monday morning is down from 18 inches the National Weather Service earlier pegged as the maximum that could fall.

But NWS forecasters warn that snow plus sleet and freezing rain could leave a “glaze of ice” on roads and make driving “very difficult or even impossible,” according to winter storm watches posted at 4:05 p.m. Thursday by the NWS office in Greer, S.C.

The watches predict 3 to 11 inches of snow and sleet from Saturday night until Monday morning for the Charlotte region and 1 to 8 inches for the N.C. mountains.

A 4 p.m. NWS predicted-snowfall map, however, shows 8 to 12 inches are expected in most or all of Mecklenburg, Gaston, Lincoln, Catawba, Cabarrus, Iredell and Rowan counties. Extreme southern Mecklenburg County could see 6 to 8 inches, according to the map, with 3 to 4 inches in Monroe and Rock Hill.

4 p.m. Thursday snowfall prediction map.JPG
A 4 p.m. Thursday National Weather Service predicted-snowfall map shows 8 to 12 inches are expected in most all of Mecklenburg, Gaston, Lincoln, Catawba, Iredell and Rowan counties. Extreme southern Mecklenburg County could see 6 to 8 inches, according to the map. Screen grab of NWS map

As recently as 6:45 a.m. Thursday, an NWS predicted-snowfall totals map showed up to 18 inches possible in northern parts of Charlotte and Mecklenburg County.

But there’s also a chance that extreme south Charlotte will get 6 inches or less, meteorologist Scott Krentz of the NWS office in Greer told The Charlotte Observer in an interview Thursday around noon.

“Road conditions could deteriorate as early as Saturday night, with highway travel continuing to be impacted through early next week,” Thursday’s winter storm watch warned. “Visibility may drop to less than a half mile during periods of heavy snow. Widespread, prolonged power outages are possible.”

The National Weather Service on Thursday afternoon lowered its overall estimated snowfall totals due both to more sleet expected beginning at 11 a.m. Sunday and less overall moisture anticipated to fall in any form Saturday night through Monday morning, NWS meteorologist Jake Wimberley told the Observer at 7 p.m. Thursday.

Expected weekend snowfall amounts for the Charlotte region will grow more certain when the NWS expects to issue a winter storm warning on Friday, NWS meteorologist Scott Krentz told The Charlotte Observer Thursday.

In a statement at noon Thursday, Gov. Roy Cooper urged North Carolinians “to watch the forecast closely and prepare their homes and families ... for the first major winter storm of the season.”

Cooper said that while “the forecast is still evolving ... everyone needs to be ready for cold temperatures, hazardous driving conditions and the possibility of power outages.”

The record two-day snowfall for Charlotte in December is 11 inches, set Dec. 29-30, 1882, Krentz said. National Weather Service records started in 1878, he said.

Charlotte’s all-time snowfall record is 12.1 inches, set on Jan. 7, 1988, Krentz said.

Ice predictions for the southern half of Mecklenburg County are between a tenth and a quarter-inch, and nearly a half-inch in Union County and York County, the NWS predicted Thursday morning.

Meanwhile, “local 20-plus amounts are possible across higher east facing mountain and foothill locations,” the National Weather Service early Thursday.

“Dangerous freezing rain and sleet accumulations in excess of one half an inch continue to be possible with the high totals and therefore impacts between I-85 and I-40 outside of the mountains.”

Areas east of Charlotte, including Monroe, could see 6 to 8 inches of snow, while cities south of the state line in South Carolina will have 8 to 12 inches as far southwest as Spartanburg, said the National Weather Service.

Bundle up, as wind chill values of 20 to 30 degrees are predicted throughout the Charlotte region. “Hypothermia or frost bite possible with extended exposure,” the NWS said in its 5 p.m. Wednesday update.

Forecasters predict snow would likely start after 9 p.m. Saturday, when temperatures will fall to 31 degrees, said the National Weather Service.

However, Sunday will see the worst of it, with a mix of snow and freezing rain before 10 a.m., then freezing rain from 10 a.m. to 4 p.m., changing to snow after 4 p.m. The high for the day will be 34 degrees and the chance of precipitation is 80 percent, said the National Weather Service.

A snow and sleet mix is predicted Sunday night and will continue through Monday morning, before switching to rain and sleet at noon. The high Monday will be 37 degrees, and the chance of precipitation is 70 percent.

The type of “wet” snow expected with the system could cover roads and down power lines and tree branches, the Weather Service warned. Less than a half inch of a freezing rain-ice mixture is possible in the N.C. foothills and Piedmont, according to the NWS forecast.

“Snowfall amounts are highly subject to change given any variability in track of weather system and temperature forecast,” the NWS cautioned beside its map.

“We’re very hesitant to give estimates, because this is heavily subject to change,” Trisha Palmer, a meteorologist with the NWS office in Greer, told The Charlotte Observer in a phone interview at 5:30 p.m. Wednesday. “It is going to change.”

The NWS total predicted snowfall map is for snow that could fall between 7 a.m. Saturday to 1 a.m. Tuesday. Palmer told the Observer that much of the snow should begin arriving early Sunday.

Joe Marusak: 704-358-5067; @jmarusak
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