A Derecho raced across the Keystone State of Pennsylvania Wednesday and impacted the City of Philadelphia with winds near 90 mph around mid day. A Derecho is defined by the National Weather service as a “widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms,” Often straight line winds cause most of the damage. The line or cluster of storms developed just SE of Lake Erie and continued to the Jersey Shore. The distance was over 300 miles and only took about 5 hours. The National Weather Service declared the event officially a Derecho before the end of the day.
For Virginians this conjures up the memory of the Derecho of 2012 that raced into the Commonwealth from West Virginia and caused widespread damage and power outages that lasted for days.
The Derecho in Philly was followed later that evening by a cluster of storms that prompted the issuance of a tornado warning for Center City Philadelphia, although no tornado was reported to have touched down in the Metro area Wednesday.