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This loop of GOES-8 6.7 micrometer InfraRed (water vapor) imagery shows a mid-level dry slot advancing east-northeastward across the central Appalachian and Mid-Atlanic regions on 09 March 1999. Snowfall rates were enhanced beneath the band of cold cloud tops (temperatures of -50 to -60 C, light blue enhancement) which was along the leading edge of this dry slot. Hourly surface reports are also plotted on the imagery.
In addition, a lobe of vorticity can be seen moving eastward across West Virgina toward the Washington DC area during the 18:00 UTC to 23:00 UTC time frame. Upward vertical motion ahead of this vorticity lobe helped to enhance showfall rates later in the day, after the passage of the main cold cloud band.