Measurements of the electric field E and dE/dt signatures radiated by first return strokes striking seawater in 1985 show that the average peak E and peak dE/dt are 8.6¿4.4 V m-1 and 42¿13 V m-1 μs-1, range-normalized to 100 km, after correcting for the effects of propagation. The full width at half maximum of the initial half-cycle of dE/dt is 64¿22 ns. The corresponding peak current and peak dI/dt, inferred using a simple semiempirical relationship, are 29¿15 kA and 105¿34 kA μs-1. These results are in good agreement with similar measurements made in 1984. ¿ 1998 American Geophysical Union