holly, colorado tornado 28 march 2007 bill eckrich dayweather, inc. cheyenne, wyoming
TRANSCRIPT
HOLLY, COLORADO TORNADO28 MARCH 2007
Bill EckrichDayWeather, Inc.
Cheyenne, Wyoming
Overview of Holly, Colorado
Located in southeastern Colorado on U.S. Highway 50 in far eastern Prowers County, 28 miles east of Lamar and approximately 5 miles from the Kansas state line
Population 1,048 (2000 U.S. Census)
Holly Tornado Statistics First touched down at 1957 MDT one mile south of
Holly WFO PUB Tornado Warning issued at 2000 MDT Rated as high-end EF3 Moved just east of north across the entire town causing
EF1 to low-end EF3 damage 2 fatalities, one within a day and another nearly a
month later, with 10 injuries Path length 28 miles over a 25-30 minute period Damage width in Holly was 1000 feet wide
Holly Tornado Statistics 48 structures destroyed 100+ structures damaged Event occurred outside of both the SPC slight and
moderate risk areas (12Z, 13Z, 1630Z, 20Z, 01Z) as well as the later-issued Tornado Watch #83
Colorado convection evolved from a retreating dryline possibly caused by stronger-than-forecast ageostrophic forcing from northward-propagating shortwave
SPC DAY1 OUTLOOK (20Z)
TORNADO WATCH #83
HOLLY
SYNOPTIC AND MESOSCALE
ENVIRONMENTINCLUDING RADAR AND
SATELLITE DATA
00Z 29 March 300mb
NOSE OF JET STREAK
00Z 29 March 500mb
00Z 29 March 700mb
00Z 29 March 850mb
THERMAL RIDGE
2116Z 28 March
2316Z 28 March
0200Z 29 March
IR SATELLITE
0100Z
29 MARCH
VISIBLE SATELLITE0130Z 29 MARCH
0153Z 29 MARCH
0157Z 29 MARCH
0157Z 29 MARCH
0202Z 29 MARCH
0202Z 29 MARCH
HOLLY
Prowers County
Kiowa County
Kansas
EF3 Damage in Holly
WFO Pueblo
EF3 Damage in Holly
WFO Pueblo
High-end EF3 Damage 12N of Holly
WFO Pueblo
High-end EF3 Damage 12N of Holly
WFO Pueblo
Courtesy Ty Harmon - KLMR
Courtesy Ty Harmon - KLMR
Courtesy Ty Harmon - KLMR
Courtesy Ty Harmon - KLMR
CONCLUSIONS Large and deep storm system over the central Rockies Large-scale ascent across eastern Colorado, southwestern
Nebraska, western Kansas and the Oklahoma/Texas panhandles
Surface winds ahead of the dryline backed with time as the shortwave/jet streak approached
Dryline retreated SRH increased with backing winds relative to storm
motion
CONCLUSIONS First tornado deaths in Colorado since June
27, 1960 Only the second killer tornado in Colorado
since 1950 Earliest strong tornado in Colorado history
Previous: 3/29/1910 in Sedgwick County Earliest killer tornado in Colorado history
Previous: 4/30/1942 in Bent/Kiowa counties
CONCLUSIONS
Prowers County has had only one prior significant tornado
June 24, 1968 One injury Occurred within one mile of Holly