A rare moment of timing is bringing potentially record-breaking snowfall to south Louisiana, weather experts say.

Bitter cold dropping down from the Arctic has combined with a fairly common, moisture-laden low-pressure system out of the western Gulf of Mexico to dump 2 or more inches of snow across the lower half of the state since early Tuesday morning, with blizzard conditions in Lake Charles.

In reports from early Tuesday, forecasters with the National Weather Service in Slidell predicted snow would be concentrated in a 30- to 40-mile-wide band along Interstates 10 and 12, highways that track the Gulf coastline.

Vincent "Vinny" Brown, an LSU climatologist, explained that the low-pressure system in the Gulf isn't particularly strong and isn't reaching communities farther north and away from the coast.

"That system is just rotating counterclockwise and just throwing Gulf of Mexico water vapor up along the coast. If it was 50 degrees outside, they just wouldn't have gotten rain. I mean, it's just the system wasn't overly strong. You know the rainfall would have stopped across central Louisiana," Brown said.

Snowfall has been reported as far north as Alexandria, though it was beginning to taper off mid-morning Tuesday, said Stacey Denson, a meteorologist with the Weather Service's Lake Charles office. Snowfall has also been reported in Violet, southeast of New Orleans.

The western part of the state has been hit with some of the heaviest snowfall reports in the morning hours. Meteorologists out of the Lake Charles Weather Service office issued a first-ever blizzard warning until noon Tuesday for Jefferson and Orange counties in Texas and Cameron, Calcasieu, Jeff Davis, Acadia, Vermilion and Lafayette parishes in Louisiana.

Blizzard warning conditions mean winds with gusts of up to 35 mph and road visibility of one-fourth of a mile or less.

Lake Charles had 4 inches of snow. The coastal Vermilion Parish community of Kaplan saw 7.5 inches so far, according to the Weather Service.

Members of the Kozma family slide down the hill at Moncus Park during the 2025 snow fall on Tuesday, January 21, 2025 in Lafayette, La..

By midmorning, snowfall had ranged from 1 to 4 inches farther east, the Weather Service reported: 4 inches in Baton Rouge and Watson, 1 inch in New Orleans and 3.5 inches in Mandeville.

The cold temperatures are coming from a not uncommon expansion in the polar vortex, which are counter-clockwise rotating air currents that typically hang over the Arctic. Another Polar Vortex also exists over Antarctica.

Brown explained that, at times, the polar vortex can stretch out and cause the Jet Stream to dip farther south. That change allows cold air to spill down across Canada and the Great Plains east of the Rocky Mountains. With few major topographical features to slow the cold air's downward path, it easily slips down to the Gulf Coast.

"Once that cold air gets into central Canada and starts heading south, it's like pouring water on a table. There's nothing between the Canadian border and the Gulf Coast. It's relatively flat east of the Rockies," he said.

Brown added that this cold air just happened to be in place when the low-pressure system from the Gulf emerged.

"One of these things spun up at a perfect time when the cold air spilled south," he added.

He pointed out another change in the polar vortex brought sharp cold temperatures to south Louisiana in February 2021, but the moisture from the Gulf wasn't around that time.

Lauren Nash, a meteorologist with the Baton Rouge/New Orleans National Weather Service Office in Slidell, said despite the forecast of concentrations around I-10 and I-12, meteorologists were seeing waves of snowfall in the morning hours of Tuesday.

She said that predicted concentration could emerge later as snow continues to fall.

Snow is expected to continue in Baton Rouge and New Orleans through the mid-to late afternoon as the low-pressure system moves west to east.

Editor's Note: This story was updated at 12:25 p.m. Tuesday, Jan. 21, 2025, with information about the blizzard warning in the Lake Charles area.

David J. Mitchell can be reached at .