EF1 tornado in St. Charles Parish, Louisiana

An EF-1 tornado tracked across parts of St. Charles and Jefferson Parishes, affecting the community of Avondale, LA. This tornado began over the Salvador Wildlife Management Area as evidenced by a well-defined 15-20 yard wide path of damage to marsh vegetation oriented southwest to northeast that was collocated with an intensifying area of rotation on both TMSY and KHDC. This damage path gradually broadened and fluctuated in intensity causing minor damage to trees as it traveled over uninhabited and inaccessible marsh areas. The tornado damage path evidently became larger and more noticeable again near Bayou Verret. A clear path of tree damage was evident on high resolution satellite imagery spanning to approximately 300 yards wide with numerous trees damaged or displaced as the tornado exited St Charles Parish and crossed into Jefferson Parish 1.35 miles south of Highway 90 along Bayou Verret.

A mesoscale convective system formed on the eastern side of Post-Tropical Storm Arthur on June 18th. Favorable low level winds allowed for multiple mini-supercells to form on the leading edge of the mesoscale convective system resulting in several tornadoes impacting the Houma and New Orleans metro areas. These tornadoes were rated as EF-0 and EF-1 events. Additionally, the mesoscale convective complex tapped into a region of deep tropical moisture with atmospheric moisture content well above normal levels for mid-June. This resulted in several significant flash flooding events in portions of the Houma and New Orleans metro areas including the cities of Houma, Kenner, and Slidell. Another area of heavy rainfall from thunderstorms formed over central Louisiana near the center of Post-Tropical Storm Arthur producing flash flooding in portions of Pointe Coupee Parish. Lingering moisture and weak upper level troughing associated with the slow moving remnants of Post-Tropical Storm Arthur produced additional thunderstorm activity on June 19th. This activity was focused in metro New Orleans where a brief EF-0 tornado developed in the community of Arabi. On June 20th, another band of thunderstorms developed along a lingering boundary stretching from coastal Louisiana toward New Orleans. This band of thunderstorms produced heavy rainfall and impacted portions of the Houma and New Orleans metro areas producing a few flash flooding events in Houma, Destrehan, and Kenner.