Attached image is Cary Hall construction taken September 25, 1927. Image is courtesy of the Purdue e-archvies.
Note in the image the cumulus humilis clouds. That day saw the high reach 77 after a morning low of 56.
An unseasonably strong, historic tornado outbreak took place September 29, 1927 from Oklahoma to Indiana.
This followed a heat wave in mid-September the 15th being the warmest September 15th on record for the Lower 48 as a whole!
At least 12 tornadoes occurred, the strongest likely being low-end EF4 that hit St. Louis, Missouri, destroying homes & buildings over 200 city blocks. Damage in St. Louis alone was around $3 BILLION (inflation-adjusted). At least 78 people were killed (some reports of 88) & nearly 600 injured (some reports of up to 660).
Two other tornadoes in the outbreak were strong, solid to high-end EF3s, the others being EF2s.
An apparent EF2 tornado tracked 33 miles from Edgar to Vermillion County, Illinois, then Vermilion County to Fountain County, Indiana.
Lifting just southwest of Veedersburg, the tornado injured 3 people & damaged or destroyed numerous farm buildings, killed livestock & destroyed crops in a path up to 1/4 mile.
Pieces of debri lofted up by the tornado from farm buildings reportedly fell up to 9 miles upstream near modern-day Fountain Central High School.
The EF2 rating was assigned using the same parameters as those in NWS survey taking into account (it may have been higher than 115 mph, but there are no other parameters to based the EF rating on):
1. The total destruction of farm building
2. Wood post & beam construction with wood roof trusses & wood panel siding
3. Wood roof & large doors
4. Assumption of less than 2500 sq. ft. area for average building
It is possible that the same embedded storm in the evolving likely squall line produced the sporadic wind damage from Fountain to Wabash County, Indiana.
The storm that produced the EF2 tornado was likely the one that produced the wind damage east of Veedersburg with "several fields of corn" laid down "by the wind" of the storm.
Several structures were struck by lightning in the storm's path & rainfall was torrential with flash flooding reported. 2-3' of water was reported in some crop fields as ditches & creeks were overcome by the rainfall rates.
"Wind storm" knocked down a barn & some outbuildings south of West Point & trees were downed on the south side of Lafayette.
Storm was strong for September with 1 pm surface pressure reading down to 990 mb near Des Moines with strong cold front slicing southwestward.
Storm was in rapid deepening phases with as it tracked from Nebraska to Iowa, coinciding with peak in tornado occurrence.
Rainfall totals were heavy.
Precipitation rates are shown in the map below showing the storms developing & gelling into a mass of heavy rainfall & likely squall line of storms.
Note the warm temperature anomalies ahead of the system & unseasonably cold weather in the West. This shows the strength of the upper trough & the reason for the surface low rapidly deepening.
This was the result a strong core (jet streak) of upper level winds rounding the bend & including the rapid deepening of the surface low on the lee side of the Rockies in the Plains.
This also resulting in the strengthening of wind fields through the troposphere.
Winds were abnormally strong at the surface ahead of the storm from the south.
Note the abnormally low surface pressure for the time of year in the Plains showing the October- to November-like strength of the storm system.
Winds tended to shift more to the southwest with height in the troposphere.
This led to the vertical shear with the strong speed shear.
Storms appeared to be racing at 60-65 mph southwest to northeast, while winds of 25-35 mph at the surface & up to 50 mph at 5,000' from the south resulted in a 50-degree deviation in the wind from 180 to 230 degrees from the surface & 5,000' to 12,000'.
For the September 29-September 30 8a-8a period, 5,000' winds averaged up to 19 m/s or 43 mph, peaking at an average of 50 mph as the storms moved through St. Louis & Illinois.
The nose of that peak low-level jet couple with the drop to 990 mb at Des Moines coincided with the violent EF4 tornado at St. Louis.