With a fast forward speed, confirmation of a low-level circulation on July 20 became difficult.[46] Convection increased in curvature on July 21,[47] and several islands in the Lesser Antilles issued tropical storm warnings and watches. After it passed north of Barbados, a Hurricane Hunters flight failed to report a closed low-level circulation, and it is estimated the depression degenerated into an open tropical wave late on July 21. The remnants brought a few showers to the Lesser Antilles,[42] and after tracking into the Caribbean Sea redevelopment was prevented by increased wind shear.[48] The northern portion of the wave axis split and developed into Tropical Depression Seven.[42]