An Examination of the Mesoscale Environment of the James Island Memorial Day Tornado

On 30 May 2005, an F-1 tornado impacted the James Island community in Charleston, SC, during the early morning hours. The event occurred on a holiday during a climatologically rare time of day. Base radar data and mesoscale analyses indicated the potential severity of the developing situation and timely warnings were issued by the NOAA/National Weather Service (NWS) Forecast Office in Charleston, SC (CHS). The tornado was on the ground for approximately 0.1 mi and produced tree and some structural damage along its path before emerging into the Atlantic Ocean as a large waterspout near the mouth of Charleston Harbor. The tornado was spawned from a cluster of severe thunderstorms in the warm sector south of a strong southwest to northeast oriented baroclinic boundary. A weak surface low propagating northeast along the boundary helped to back winds ahead of the cyclone, which substantially increased low-level helicity in the Charleston area as these storms approached. A detailed examination of the mesoscale conditions leading up to tornado genesis will be discussed.