Electric field (E) soundings through the convective regions of two types of isolated thunderstorms are examined. Analysis of seven soundings through strong updrafts of isolated supercell storms show that the basic E structure there has three |E| peaks: a positive peak near 8 km height, a negative peak near 10.5 km, and a positive peak near 12 km. Strong updraft soundings are those with average balloon ascent rates in excess of 10 m s-1. The basic charge structure in strong updrafts of supercells has four charge regions of alternating polarity. The lowermost charge is positive, between about 4 and 8 km, and the uppermost region is negative. All the supercell updraft soundings are incomplete due to balloon burst or lightning-induced instrument destruction below cloud top. Six supercell soundings that ascended outside strong updrafts are used to show that the E and charge structures there are more complex than within the strong updrafts. Analysis of 15 new or previously published soundings through small, New Mexican mountain thunderstorms indicates that the basic E structure in or near their convective cores consists of three |E| peaks: a lower positive peak at about 5 km height, a midlevel negative peak near 6.5 km, and an upper positive peak near 9.5 km. The basic charge structure near the center of New Mexican storm convection has four charge regions, alternating in polarity, with a positive charge region lowest. Soundings in New Mexican convection that did not ascend near the convective cores show more complex E profiles and charge structures. ¿ 1998 American Geophysical Union