1966 & 1967 saw multiple late severe events to outbreaks in & near our viewing area. They were also very wet Decembers with record daily rainfall for the events in some areas. Two Decembers saw unusually warm, wet weather. Both years saw payback in January with big blizzard for part of the area in January 1967 & heavy snow & record cold in January 1968.
In 1967, even between the December 11 & 21 outbreaks in Indiana, severe weather occurred elsewhere in a very active, spring-like period. Two damaging tornadoes hit Huntsville, Alabama alone on December 18. 2 were killed & many other injured. Early on December 19, tornadoes hit the Birmingham, Alabama area.
January 24, 1967 saw another tornado outbreak with highly-unusual winter F4 at near St. Louis, Missouri.
On December 8, 1966, rare December severe weather event produced F2 tornadoes in Jasper & Montgomery counties. 1 person was injured in Jasper County with additional straight-line wind damage in White & parts of Montgomery County. The wettest December day on record occurred at Logansport with this event when 3.20” rain fell.
Warm front surged northward, bathing us in 60s with dew points as high as 61.
Training storms along & ahead of the strong cold front hit the area midday through afternoon.
Highs in the 60s were widespread over the viewing area & region. Even Grand Rapids, Michigan hit 64 & Detroit 66. Rochester, New York hit an impressive 69.
On December 11, 1967, 7 tornadoes are confirmed in Indiana along with damaging straight-line winds as strong low pressure moved north-northeastward from Memphis, Tennessee to northwest Michigan. One person was injured from an F1 in Putnam County & wind gusts to 65 mph occurred in southeast Montgomery & Boone counties.
After such a wet, cool fall, 30-40% of the soybean & corn crop in Indiana & Illinois was still unharvested. Tornadoes & damaging winds damaged & even flattened acres & acres of crops. Structural damage from the tornadoes alone amounted to $2 million (inflation-adjusted). Many other tornadoes, wind & hail occurred in the southeastern United States with damage in the tens of millions of dollars. Just 10 days later, another significant severe weather outbreak would occur in the same regions of Indiana with more heavy rainfall, which continued to delay the harvest.
This system was unusual in that it originated in the Gulf of Mexico & moved north.
December 21, 1967 was the wettest December day on record for several locations accompanied by the second rare December severe weather event in a week in Indiana. Straight-line wind damage occurred in Montgomery County with an F3 tornado in Grant County. At least 4 tornadoes were confirmed in Indiana with damage amounting to $2.3 million (inflation-adjusted). 3 people were injured in Grant & Wells counties.
The rain & storms also produced heavy rainfall. December daily rainfall records were set with 3.94” at Kentland, 3.48” Frankfort, 3.15” at Winamac & 3.01” at Peru. 1967 ended up as the wettest December on record at Delphi with 7.02”.
A warm front surged northward through the area in the early morning hours of December 21. Note how it was an impressive 66 with a dew point of 63 at 1 a.m. at St. Louis & Springfield, Illinois reported a t'storm with 63 & a dew point of 61.
Highs in the 60s were widespread over the area, but once the cold front passed, temperatures tanked. Chicago dropped from 61 to 19, while Indianapolis dropped to 26 after reaching a high of 67. La Cross, Wisconsin reached 55, then dropped to 10 around midnight.