| January 20 2025 |
Central Appalachians to Northeast Winter Storm: (1/19/25 - 1/20/25)
By: Frank Pereira, WPC Meteorologist
Meteorological Overview:
A strong arctic front swept southeast across the eastern United States on January 18–19 before stalling along the East Coast. A surface low developed over eastern North Carolina Sunday morning and tracked rapidly northeastward along the boundary, deepening as it moved along the Mid-Atlantic coast to pass just south of Long Island by that evening. In the upper levels, the left-exit region of a 150+ kt jet streak promoted strong divergence aloft and steady surface cyclogenesis. At mid-levels, strong 850–700 mb frontogenesis (FGEN) developed along the arctic boundary as warm advection from the south clashed with the frigid air mass. This setup produced a broad band of moderate to heavy snow from the Allegheny and Laurel Highlands early Sunday into eastern Pennsylvania, northern New Jersey, and the Lower Hudson Valley later in the day. Embedded mesoscale bands generated snowfall rates of 1–2 inches per hour, with localized rates up to 3 inches per hour in far western Maryland, reducing visibility below a half mile in some locations.
The surface low continued its northeastward track Sunday night, focusing the heaviest snow northwest of the Interstate-95 corridor from New York to Boston and then along coastal Maine. In these areas, mesoscale banding and frontogenesis aligned efficiently with the dendritic-growth zone (DGZ) to produce widespread snowfall rates of 1–2 inches per hour. In contrast, across the New York City metro, Long Island, and along the southern New England coast, precipitation began as rain or mixed precipitation. This warm onset limited total accumulations, even though rates eventually approached 1–2 inches per hour as cold air deepened. Despite these intense bursts, the system’s fast forward motion limited the duration of heavy snow at any one location as the low traversed the Gulf of Maine overnight and reached the Canadian Maritimes early Monday.
Impacts:
Although the system was progressive, it produced a continuous swath of 4–8 inches of snow from the central Appalachians to Downeast Maine, with localized maxima over 10 inches across central West Virginia and far western Maryland. Following the storm’s passage, the pressure gradient between the departing low and building arctic high produced widespread subzero wind chills, which dropped as low as –10°F to –20°F in the mountains. As temperatures fell rapidly Sunday night, untreated and previously wet road surfaces refroze, prolonging hazardous travel into Monday morning.
Heavy snow, poor visibility, flash freezing, and subzero wind chills led to widespread travel disruptions across the Mid-Atlantic and Northeast. Pennsylvania experienced a major pile-up on Interstate 80 in Clearfield County, while officials in New Jersey declared states of emergency and imposed commercial vehicle restrictions. More than 1,200 flights were canceled at airports in major cities, including Boston, New York, Newark, and Washington. Ground-delay programs were implemented at JFK and Newark. While only scattered power outages were reported, the storm occurred ahead of a significant arctic outbreak that drove record electricity demand during the days that followed.
