Complex sentence: In the case of El Reno, the wrapping rain bands also led not to a narrow corridor of clear air close to the tornado rather these rotating curtains of rain were the outer circulation of the tornado itself.
Split into simpler sentences: In the case of El Reno, the wrapping rain bands also led not to a narrow corridor of clear air close to the tornado. Rather, these rotating curtains of rain were the outer circulation of the tornado itself.