Maryland weather: Here's why Thursday's storm produced more snow than expected

You can blame a persistently chilly northeast wind for the several inches of snow that fell across Central Maryland on Thursday.

It prevented more precipitation from falling as sleet or freezing rain in Baltimore and along Interstate 95. Forecasters had predicted warming air to create a wintry mix of precipitation by late Thursday morning, but temperatures were stubborn to rise, even into Thursday afternoon.

Highs were forecast in the upper 30s to around 40 degrees, but temperatures remained in the lower 30s around the region by 3 p.m.

Usually, freezing temperatures are hard to come by this time of year when storm systems move up the East Coast. But a steady flow of cold air from eastern Canada remained in place through much of the day, steered by a high pressure system off the coast of Maine, said Kevin Witt, a meteorologist at the National Weather Service’s Baltimore/Washington forecast office.

“This was one of those rarities in November where cold air happened to be in place, and it wasn’t going anywhere fast,” he said.

Meteorologists had predicted a likely inch or less along I-95 and as much as 3 inches to the northwest, in the higher elevations of Carroll, Howard, Baltimore and Harford counties.

Instead, the weather service reported as much as 8.3 inches in Thurmont, 5 inches in Westminster and Parkton, 4.5 inches in Norrisville, 2.8 inches in Bel Air, 2.5 inches in Perry Hall, 2 inches in Columbia and 1.7 inches at Baltimore-Washington International Thurgood Marshall Airport.

Precipitation transitioned to sleet and rain by early afternoon in Baltimore and along I-95, and the change-over was expected to continue across the region into the evening — except, perhaps, along the Mason-Dixon Line, Witt said.

A chance for more snow and sleet showers is possible on the back end of the storm late Thursday night, he said.

Thursday's snow is Baltimore's earliest in 22 years, and heaviest for November since 1989 »

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