This tornado outbreak was the second largest in recorded history. The largest occurred in early April 1974. There is a theme here; the super tornado outbreaks occur early in the spring when the temperature contrast is the largest and hence the winds at all levels of the atmosphere the strongest.
The pattern leading up to this severe weather event featured record cold and snow during the second half of March. In fact, March 1965 with a mean temperature of 16.9 was the coldest at the National Weather Service (NWS) site near Negaunee until the 15.6 degree mean set this March. Spring finally made a push to the north during the second week of April 1965 (as it has this past week) and set the stage for disaster.
The NWS in Detroit has an excellent summary of the outbreak here. Southeastern Lower Michigan was hit hard. Several F-4 tornadoes raked the region. Scores were killed and damage was well into the multi-millions of dollars. In all, 47 tornadoes were confirmed from Michigan to Alabama with 271 people killed.
Farther north, Upper Michigan was the place to be on April 11, 1965. It was an unpleasant, raw day. However, we were on the cold side of the system that besieged the southern part of the state. In Marquette, the Weather Bureau (now the NWS) reported 0.23 inches of rain with a high of 42 and a low of 33 degrees.
We will be on the cold side of a system developing in the central U.S. this weekend. It is all part of a transition back into a cold pattern expected next week. A low-pressure wave will move in from the west on Saturday. A cold rain is likely and some wet snow will likely be mixed in. In fact, there could be some accumulation of slushy snow over the far northern U.P. with this event. Then northerly winds set in starting on Sunday. The next wave of low pressure passing to our south and east could bring some snow to eastern sections Sunday night into early Monday. The big story will be the very cold air for mid-April due in here next week.