What is a “bombogenesis”? Does it ever occur in the Chicago area?
Bombogenesis is a term applied to a rapid intensifying low pressure system in which the central pressure drops at least one millibar an hour for 24 hours. In terms of inches of mercury that would equate to pressure falling at least .03’’ an hour for 24 hours or 0.72”. This type of rapid intensification often occurs with cold-season storm systems off the Atlantic Seaboard dubbed nor’easters which produce many of the region’s major snowstorms. While not as common, these storms do occur in the Midwest. On the night of December 14, 1987 a low pressure system moving northeast from the southern Plains “bombed out” on its track to southern lower Michigan bringing the Chicago area a prolonged period of thundersnow that buried the city in 8 to 12 inches of heavy, wet snow.