Eastern Wyoming Tornado
April 12 1967
Jonathan D. Finch
Boulder Area Tornadoes Webpage
Cheyenne Area Tornadoes Webpage
US tornado cases webpage
May 7-8 1965 Front Range Tornado
June 14-17 1965 Front Range Superstorm
April 23 1960 Cheyenne Ridge Tornado
The July 16 1979 Cheyenne Tornado
High plains and front range topo maps
On April 12, 1967 , a thunderstorm developed west of Cheyenne, WY and moved NE over over open mostly
wide open country. The first tornado was seen 4 miles south west of Veteran, WY. This tornado moved NE and then
north, passing 4 miles west of Torrngton. No large
hail was reported. Its is possible that the core of this storm on
the northern and northwest side of the storm hit no
populated areas. Also, phone calls were not made to collect
hail reports in the 1960s. Hail was only documented
if someone actually called the report in to the office. Hail as
large as golfballs did occur in the Nebraska
panhandle near Chadron.
At 12 UTC April 12 1967, a very deep 500mb upper
trough was located over southern California. A 700mb
warm plume covered the plains with 700mb temps up to
7C. A high level speed max was located over the
northern plains but another jet streak was entering
southeast Arizona. 500mb temps were fairly cold (17-19C)
from ABQ to DEN to RAP. Even though the 700mb
temperature was cooler at Albuquerque at 12 UTC (-1C) the
700mb cold front had not passed yet. It is just that
elevated heating and rapid transport downstream was leading to
warmer 700mb temperatures to the east of Albuquerque(ABQ).
By 18 UTC, a warm front stretched from central
Colorado into northern Kansas and Missouri. Low level upslope
flow was apparent across northeast Colorado, western
Nebraska and southeast Wyoming. This in conjunction with
elevated heating was leading to rapid
destabilization across the central high plains and front range. A
front stretched from western CO to near ABQ.
The cold front passed ABQ shortly after 18 UTC as shown by the
surface observation sheet. Another cold front stretched from North Dakota into eastern Wyoming. A well defined
outflow boundary existed across the southern plains.
A surface dryline was located from west Texas to just east of
Goodland. I was able to pinpoint the location of the
dryline by using the surface observation sheets from Goodland
and Garden City. I pinpointed the warm front using surface observations from various sites including Akron, Denver
and Goodland. The warm front was a little harder to
find across western Kansas.
By 20 UTC, the warm front stretched from just south
of Denver to just south of Akron to near North Platte. The
pacific cold front was about to pass Las Vegas, NM.
The dryline had pushed east of Garden City. The dryline
was well east of Goodland, KS but had not yet passed
east of Imperial, NE. The T/TD at Cheyenne were up to
59F/39F with upslope winds.
A thunderstorm developed west of Cheyenne around 3
pm and moved generally northeast. At 5 pm this storm produced
a tornado southwest of Veteran, WY. This tornado
moved northeast then north destroying 10 buildings. Severe weather
probably occurred between Cheyenne and Veteran but
this is a sparsely populated area.
The surface T/Td at Cheyenne and Fort Collins at 18
UTC were 53F/39F and 61F/41F respectively. The surface
dewpoint at Muskogee was 62F/60F. However, the
theta-e was actually higher at Fort Collins and about the same at
Cheyenne. This is despite the dewpoint being much
lower on the front range. But why? The key is that elevated heating
compensates for the lack of moisture on the front
range. In this case, the potential temperature was 32F higher in
Cheyenne than Muskogee even though it was 9F cooler
in Cheyenne. Since the 500mb temperature was much cooler
at Cheyenne and Fort Collins, the lifted index was
much lower there.
The surface T/Td at Cheyenne at 20 UTC was 59F/39F.
The surface T/Td at Topeka and Emporia were 67F/60F
and 70F/57F respectively. However, the theta-e was
actually about the same at all 3 locations. Again, the
elevated heating. Since the 500mb temperature was
much cooler at Cheyenne, the lifted index was much lower
An approximate sounding for Cheyenne at 20 UTC shows
about 1800 j/kg surface based CAPE. I used the 00
UTC Rapid City wind profile at and above 500mb. The
winds veer between the surface and 500mb, but the
speeds and directions in this layer are not known.
The 700mb wind field on the high plains, front range and
intermountain west can be very difficult to resolve
since 700mb is on the boundary layer. Sometimes 700mb is in
the moist layer and sometimes not. The only way to
know the low level wind profile on the front range is to have a
dense sounding or profiler network. However, there
is greater than 50kts of shear between the surface and 400mb
or in the lowest 6 km. This is very respectable.
I also created an approximate sounding for
Scottsbluff, NE which is east of where the tornado occured. The surface
based CAPE is about 1300 j/kg.