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This loop of GOES-8 10.7 micrometer longwave InfraRed (IR) imagery shows a band of cold cloud tops (temperatures -50 to -60 C, yellow to red enhancement) advancing east-northeastward across the central Appalachian and Mid-Atlanic regions on 09 March 1999. Snowfall rates were enhanced along this band of cold cloud tops, which was along the leading edge of a mid-level 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 (cloud top temperatures of -30 to -40 C, blue to green enhancement) 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.