This is a good "in situ" (meaning in place) cold air damming case. The event began as a classic case with high pressure over the northeastern states pushing cold air south down the east side of the Appalachian Mountains. The high pressure system moved off the East Coast but cold air remained in place for an extended period of time. The low pressure trough associated with a developing warm front along the coast, along with a storm system approaching from the west, helped maintain the definition of the high pressure ridge to the east of the mountains. The northeast winds from the high pressure ridge kept the cold air in place. The event finally ended as the warm front moved farther inland from the coast and eroded the cold air.
The sequence of maps for surface analysis starts at 4 PM EST February 14, 2016, and ends at 4 AM EST February 16, 2016, and is for 3-hourly increments. Note that the time specified in the lower left corner of each map is in Zulu (Z) time, equivalent to Coordinated Universal Time (UTC) and Greenwich Mean Time (GMT).