Values of the positive and negative polar conductivities under summer thunderstorms in Florida are highly variable and exhibit a significant electrode effect, but the total conductivity usually remains close to values found in fair weather, 0.4 to 1.8¿10-14 S/m. With these values a method proposed by Krider and Musser in 1982 for estimating the total conductivity from changes in the slope of the electric field recovery following a lightning discharge will be extremely sensitive to small time variations in the local Maxwell current density and must be modified to include these effects. ¿ American Geophysical Union 1992