The National Weather Service in Sterling, Va., did a storm survey in Frederick County, Md., around New Market and just north of Mount Airy and found damage consistent with EF-0 and EF-1-strength tornado winds. These storms were part of a line of thunderstorms that stretched originally from Hagerstown southward through Front Royal. This was actually the second line of thunderstorms to come through the region Saturday afternoon and evening.
The line of thunderstorms progressed to the east where some bowing out of the line was first noted around Leesburg, Va. There was also a bit of a line-echo wave pattern (third picture down) noted in the line after this happened. When that occurred, a Tornado Warning was placed over parts of Loudoun, Frederick and Montgomery counties. No tornado was reported with that part of the line, though wind gusts over 50 m.p.h. were common through Leesburg on our WeatherBug Network.
As the line continued to move east. Two more line-echo wave patterns were noted along the line. One just around New Market, Md., and one farther to the north in northern Frederick and Carroll counties. An additional warning was placed over the storm near New Market, and that is when a tornado did EF-1 damage with winds estimated at 90 to 100 m.p.h. This same tornado did EF-0 damage with maximum winds of 70 to 80 m.p.h. 3 miles SE of Unionville near Glissans Mill Road and Woodville Road. This tornado continued to move northeast until it finally ended in Carroll County by Westminster.
Official storm surveys will probably be issued today on the NWS Baltimore/Washington homepage. More severe weather, though not nearly as powerful, is expected Wednesday. We will keep you on top of the situation.