The Midwest Snow Storm of 8–11 December 1977

Conventional surface and upper-air aerological data are combined with radar and aircraft measurements to give a description of a major winter storm that deposited over 69 cm of new snow at Muskegon, Michigan, between 8 and 11 December 1977. It is shown that most of this snow occurred during four distinct episodes, three of which were related to air-water temperature contrasts as Arctic air flowed over the relatively warm surface of Lake Michigan. These four episodes have been identified as 1) pre-cold frontal, 2) post-cold frontal, 3) secondary trough, and 4) mesolow phases. During the pre-cold front phase heavy snow was associated with an advancing synoptic-scale trough. Little direct effect of the lakes was detected. Following passage of the cold front, strong northwesterly winds across Lake Michigan resulted in strong air-mass transformation with light steady snow along the downwind shoreline. The evidence suggests the presence of horizontal-roll convection as the dominant organizational mode ...