This event involved a significant deviation from initial weather forecasts, evolving rapidly from a predicted nuisance storm into a severe blizzard within 48 hours.
Factors Contributing to Storm Development
Storm Track
Early weather models indicated the storm's center would track far from the U.S. coast, leading to initial predictions of light snow for the I-95 corridor. As the storm's components converged and computers improved modeling of its path, snow accumulation projections increased.
The storm's center was eventually projected to track directly over or just southeast of the 40°N/70°W benchmark. This location is optimal for New England nor'easters, allowing the storm to draw maximum moisture from the Atlantic while maintaining cold, snow-heavy conditions along the I-95 corridor.
Bombogenesis
The storm underwent bombogenesis, defined by a central pressure drop of 24 millibars in 24 hours. This rapid pressure decrease caused the storm to intensify, drawing substantial moisture from the warm Gulf Stream and colliding it with arctic air.
Mesoscale Banding
A key factor in localized snow totals was mesoscale banding.
These narrow, high-intensity snow bands, typically 10 to 20 miles wide, can produce 3 to 4 inches of snow per hour.
Weather models often struggle to precisely predict the formation and location of these bands until the storm is imminent.
Combined with a high snow-to-water ratio, which allows cold air to convert minimal moisture into significant amounts of fluffy snow, these factors contributed to a forecast deviation towards extreme conditions.