An Unusual Tornado during the 1 June 2012 Tornado Outbreak in the WFO Baltimore/Washington Forecast Area

Among the twelve tornadoes (of EF-0 to EF-1 intensity) that occurred on 1 June 2012 in the forecast area of the Baltimore/Washington (LWX) National Weather Service Forecast Office (NWS WFO) in Sterling, VA, an EF-0 tornado was observed in east-central Howard County, Maryland. A survey of the damage indicated that the tornado rotated cyclonically, as environmental parameters suggested that it should. But this tornado was unusual in that it occurred beneath what appears to be an anticyclonically-rotating updraft on the left flank of a supercell thunderstorm. Although a Tornado Warning was in effect for this storm, it was the rotation beneath the cyclonic updraft on the storm's right flank that prompted the warning.

This study will exhibit radar imagery of the thunderstorms from both the Weather Surveillance Radar—1988 Doppler (WSR-88D) in Sterling, VA and multiple Terminal Doppler Weather Radars (TDWRs) in the WFO LWX service area. The TDWRs offer higher spatial and temporal resolution than the WSR-88D radar and illustrate a possible interaction between the left-flank anticyclonic updraft and a downburst in the cyclonic updraft's forward flank that may have contributed to this unusual tornado. The process by which this interaction could occur will be highlighted.