Case study of the relevant synoptic forcing mechanisms in the 24-25 January 2000 east coast snowstorm




Journal Title

Journal ISSN

Volume Title


Texas Tech University


A major winter storm blanketed the eastern seaboard with significant amounts of snowfall from 24-25 January 2000. Neither the medium- nor the short-range forecast models performed well in predicting the extratropical cyclone that left forecasters unprepared for the developing situation and scrambling to make snowfall total predictions. A broad area of low pressure first developed over the Florida peninsula and later evolved into a stronger surface low off the coast of South Carolina where rapid intensification began. Cape Hatteras, North Carolina, recorded a 29-mb pressure fall in 24 hours, which is indicative of a rapidly deepening extratropical cyclone. The path of the storm affected most of the metropolitan areas along the Atlantic coast. The Washington, D.C.-Baltimore and Raleigh-Durham, North Carolina, regions were both hit with heavy snowfall. In fact, Raleigh-Durham recorded a record-breaking 20.3" of snow, breaking the old mark of 17.9" set during 15-17 February 1902.

Several synoptic forcing mechanisms factored into the rapid intensification of this particular extratropical cyclone. One significant mechanism that contributed to intensification was the interaction of the upper-level jet with the surface low. An intrusion of stratospheric air brought anomalously high values of potential vorticity into the mid- and lower troposphere. A well-defined low-level baroclinic zone was present between the warm Atlantic Ocean and the cold Carolina terrain. Additionally, a mobile 500-mb trough was present upstream of the extratropical cyclone; this situation supported the Sanders and Gyakum (1980) findings on rapid cyclogenesis.

Techniques used to investigate these forcing mechanisms include surface and upper-air analyses. Satellite imagery and radar images were also incorporated into this investigation. Additionally, cross-sections through the extratropical cyclone were utilized to diagnose the coupling of the upper air and lower troposphere forcing mechanisms that worked simultaneously to enhance the storm strength. The use of isentropic analysis also helped with the analysis of the jet streaks and moisture flow.



Wind-snow interaction, Cyclone forecasting, Storms -- Atlantic Coast (U.S.)