The Historic Mid-Atlantic Snow storm of 5-6 February 2010. A strong storm moved across the Gulf of Mexico and up the East Coast of the United States on 5-6 February 2010 (Fig. 1). This storm produced heavy snowfall from Virginia to New Jersey. Many sites in Pennsylvania, Virginia, Maryland, Delaware, and New Jersey received record snowfall. Snowfall totals at some sites exceeded 30 inches in Maryland and Pennsylvania. Reports of snowfall in excess of 20 inches were common in the Pittsburgh, Harrisburg, Philadelphia, Washington, and Baltimore metropolitan areas.The storm total snowfall is shown in Figure 2. In terms of record snowfall, the snowfall in Pittsburgh, 21.1 inches, was a record for the date and the 4th all-time snowfall for the City behind the record storm of 24-26 November 1950 (27.4), 16-18 December 1890 (25.9), 12-14 March 1993 (25.3). At Washington, Dulles airport the 32.4 inches crushed the previous record set in January 1996. The 24.8 inches at Baltimore nudged out the old record of 24.4 inches set 16-17 February 2003 during the ?Presidents Day snow storm of 2003?. Philadelphia?s 28.5 inches was the second largest snowfall, second only to the 30.7 inches recorded on 7-8 January 1996. Finally, the 25.8 inches of snowfall at Wilmington, Delaware beat the old record set on 7-8 January 1996. Many locations set records for the date and the month. Harrisburg, PA set record for the date with 18 inches which as the 8th largest snowfall for the City. At this time the largest known snowfall was 38.3 inches in Maryland with 3.34 inches of liquid equivalent. This was the second major to historic snowstorm to impact the Mid-Atlantic region during the winter of 2009-2010. Double digit snowfalls are in a winter are relatively uncommon events in the Mid-Atlantic region. There are many aspects of this storm worthy of study. No doubt this will be a well studied event. Thus, our focus here is to document this event and show the value of anomalies in anticipating significant and potentially historic snow storms. Some NCEP forecasts are shown to demonstrate how well the models predicted the potential for heavy snow and how the models indicated a sharp area of uncertainty for the region where the heavy snow would rapidly diminish to light snow. GEFS GFS SREF heavy snow anomalies.