Great Blizzard of 1978 From Wikipedia –
The Great Blizzard of 1978 was a historic winter storm that struck the Ohio Valley and Great Lakes regions from Wednesday, January 25 through Friday, January 27, 1978. It has been cited as the worst blizzard in US history. The third lowest non-tropical atmospheric pressure ever recorded in the mainland United States occurred as the storm passed over Mount Clemens, Michigan, where the barometer fell to 956.0 mb (28.23 inHg) on January 26.

Meteorological synopsis
Late on Tuesday, January 24, 1978, surface maps revealed a moisture-laden Gulf Low developing over the southern United States, while a separate and unrelated low-pressure system was present over the Upper Midwest. In about 24 hours, the merger of the subtropical jet stream (containing a wind max of 130 knots) and the polar jet stream (containing a wind max of 110 knots) led the low-pressure system to undergo explosive cyclogenesis as it moved rapidly northward during the evening of January 25 (record low pressures were logged across parts of the South and Mid-Atlantic). To be classified as undergoing explosive cyclogenesis, a storm’s central pressure must drop at least 24 millibars, or an average of 1 millibar per hour, over a 24-hour period; the Great Blizzard dropped by a remarkable 40 millibars in that span of time.