Radars with wavelengths of 10 cm (S band) and 70 cm (UHF band) were used to acquire the vertical precipitation structure and lightning flash distribution, respectively, in a multicell thunderstorm near Wallops Island, Virginia, during about 1.5 hours of continuous observations. The storm contained six cells that appeared sequentially; two of them exhibited the features of cell merger. In all six cells, vertical growth was about 3 times faster than decay. Lightning flash density centers were determined from the number of flashes that occurred within the UHF-band radar beam per minute for each kilometer along the beam. The lightning radar echo data were corrected for side lobe effects. A bimodal distribution of lightning flash density was observed in only one cell, and it occurred during the initial stage of storm development; both the lower and the upper centers had 32 flashes min-1, centered at 7 km and 13 km, respectively. The other cells had single (lower) centers of lightning activity, with maximum flash densities ranging from 12 to 40 flashes min-1 km-1. As others before have reported, we see a positive correlation in time between the maximum lightning density and the heights of both the 40- and 50-dBZ reflectivity cores. In all six cells we observed the following repetitive patterns in reflectivity structure and lightning distribution: (1) during the initial rapid growth of a cell, lightning activity is concentrated within a region bordering on the leading edge of the 50-dBZ core of the cell and between this cell and its dissipating neighboring cell, and (2) in the decaying stage of a cell, lightning activity spreads farther into the cell.