Abstract
The characteristics of Great Lakes-induced storms and their cloud-to-ground (CG) lightning flashes are examined for four fall-winter seasons, beginning with the fall 1983-winter 1984 season. Satellite, surface, upper air, and lake temperature data were used in the analysis of the meteorological characteristics of the storms. The characteristics of the CG lightning flashes were recorded by the State University of New York at Albany Lightning Detection Network. During the 1983–87 period, the network covered lake Ontario and increasing portions of Lake Erie as a result of network expansion. Thus, both Lake Erie-induced and Lake Ontario-induced storms were selected for analysis. The storms that were examined produced three or more CG flashes on eight separate occasions. The earliest occurrence of a lake-induced storm with CG lightning was in mid-September, the latest in early December. These storms generally consisted of an enlarged, single band. Typically, only a few CG flashes were recorded per event. However, nearly 700 CG flashes were recorded during the very unusual 22–24 September 1983 event. A majority of all flashes were clustered over the eastern ends and eastern and southern shorelines of the lakes. Plateaus to the east of both lakes also appear to be favored locations for CG lightning activity. About 75% of all CG flashes lowered positive charge to ground, excluding the 22–24 September 1983 event when 70% of the flashes lowered negative charge to ground. Positive and negative flashes both were predominantly single-stroked. The median peak current of positive first return strokes was +79 kA for 22–24 September 1983 and +91 kA for the remaining seven storm periods. The corresponding median peak current values for negative first return strokes were −47 kA and −44 kA, respectively.
