The 850 temps sampled on the 18z special RAOB ahead of the line occurred only 5 times before in recorded history at the IAD site. You could tell early in the day on the 12z ILN site that something big was about to happen because the EML was evident so early in the morning. That airmass advected ahead of the complex and sustained it over the mountain. Reanalysis of the event showed that every meso model that correctly modeled the EML successfully predicted the derecho making it to the coastline. If there's on big takeaway from that event, it was that correctly sampling, identifying and modeling EMLs in the Mid Atlantic will significantly increase the ability of forecasters to anticipate these events and provide timely IDSS to the appropriate officials.