Tornadoes · United States · Kansas · 2005

F1 tornado, South Mound, Kansas, April 21, 2005

Name: F1 tornado, South Mound, Kansas, April 21, 2005
Start: 2005-04-21T23:19:00.000Z
Location: South Mound, Kansas

This F1 tornado ran 7.0 miles across Neosho County on April 21, 2005, touching down at 6:19 PM CDT and reaching 100 yards wide. It killed nobody, and did $10,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

F040 to 72 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
F2113 to 157 mph
Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.
F3158 to 206 mph
Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
F5261 to 318 mph
Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.
Unrated
The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating: F1
Date: April 21, 2005
Touchdown: 6:19 PM CDT (23:19 UTC)
Path length: 7.0 miles (11.3 km)
Path width: 100 yards (91 m)
Deaths: 0
Injuries: 0
Property damage: $10,000
County: Neosho County
Touchdown point: 37.420, -95.200
Lift-off point: 37.480, -95.120
Record number: 684

What the Weather Service recorded

One frame house was partially unroofed and one barn destroyed. Tornado crossed the Neosho/Crawford county line, 5 miles southeast of St. Paul. The tornado lifted one mile east of the Neosho/Crawford county line.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The forecast that day

The Storm Prediction Center had this point in a Moderate Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:49 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

What forecasters said that day

The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Wichita, KS wrote its last area forecast discussion before the tornado touched down at Apr 21, 2:50 PM CDT, 3 hours 29 minutes earlier.

Area forecast discussion, Apr 21, 2:50 PM CDT, 3 hours 29 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WICHITA KS
250 PM CDT THU APR 21 2005

.DISCUSSION...

TONIGHT
SEVERE WEATHER STILL A POSSIBILITY FOR SOUTHEAST KS LATE THIS
AFTERNOON INTO THE EARLY EVENING HRS, BUT ANY ACTIVITY THAT
DEVELOPS WILL QUICKLY SHIFT EAST INTO MISSOURI. SO WILL ONLY CARRY
CHANCE POPS FOR SOUTHEAST KS DURING THE EARLY EVENING TIME FRAME.

FRI-SAT
UPPER LEVEL SYSTEM CURRENTLY OVER WESTERN NEBR WILL BE OVER
NORTHEAST KS EARLY IN THE MORNING, THEN SHOULD DIVE SOUTHEAST ACROSS
MISSOURI AS KICKER SYSTEM DROPS SOUTHWARD ACROSS THE NORTHERN
PLAINS. AS A RESULT, EASTERN KS COULD SEE SOME RAIN SHOWER ACTIVITY
FOR THE FIRST HALF OF THE DAY. TEMPS ON FRI WILL BE 15-20 DEGREES
COOLER COMPARED HIGH TEMPS DURING THE PAST FEW DAYS. NORTH WINDS
WILL BECOME QUIET STRONG AND COULD FLIRT WITH ADVISORY CRITERIA
DURING THE DAY. COOL CANADIAN HIGH PRESSURE WILL BUILD SOUTH INTO
THE REGION ON FRIDAY NIGHT WITH WINDS DECREASING. TEMPS WILL BE
BELOW APRIL AVERAGES FOR SATURDAY AS COOL HIGH PRESSURE REMAINS IN
CONTROL.

SUN
DECENT CHANCE FOR SOME FROST IN EARLY THE MORNING TO START THE DAY
AS COOL CANADIAN AIRMASS REMAINS OVER THE AREA. LATER SHIFTS WILL
HAVE TO WATCH THINGS FOR A POSSIBLE FROST ADVISORY. SHOULD BE A VERY
PLEASANT DAY WITH LIGHT WINDS AND PLENTY OF SUNSHINE, AS TEMPS WARM
A FEW MORE DEGREES FROM SATURDAYS VALUES. OUR NEXT SYSTEM WILL TRACK
EAST ACROSS THE ROCKIES AND COULD BRING A CHANCE PRECIP LATE SUNDAY
NIGHT.

EXTENDED: MON-THUR
CHANCES OF RAIN/STORMS FOR MONDAY AND POSSIBLY AGAIN ON THURSDAY
WITH TEMPS REMAINING AROUND NORMAL.

STILL SOME UNCERTAINTY ON POSITION OF FRONTAL BOUNDARY FOR MONDAY,
BUT WILL NOT MAKE WHOLESALE CHANGES AND KEEP OUR RAIN CHANCES GOING.
OTHER THAN SOME SMALL RAIN CHANCES FROM SYSTEM DIVING SOUTH ACROSS
THE AREA ON TUESDAY. WILL KEEP WEDNESDAY DRY WITH OUR NEXT SHOT OF
SHOWERS AND STORMS POSSIBLY ARRIVING ON THURSDAY. LOOKING BEYOND THE
SCOPE OF THIS 7-DAY FORECAST AT THE LONG RANGE MODELS. THE LONG
RANGE MODELS ARE HINTING AT A UPPER PATTERN CHANGE FROM OUR CURRENT
BLOCKY TYPE PATTERN, TO A MORE PROGRESSIVE PATTERN. THIS COULD
RESULT IN MORE ACTIVE SPRING-LIKE WEATHER...STAY TUNED.

&&

.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT    49  65  39  63 /  10  10   5   0
HUTCHINSON      48  64  38  63 /  10  10   5   0
NEWTON          48  64  39  63 /  10  10   5   0
ELDORADO        49  64  40  63 /  10  20  10   0
WINFIELD-KWLD   50  66  40  64 /  10  10  10   5
RUSSELL         45  64  35  63 /  10  10   5   0
GREAT BEND      46  64  35  64 /  10  10   5   0
SALINA          48  63  37  63 /  10  10   5   0
MCPHERSON       48  63  37  63 /  10  10   5   0
COFFEYVILLE     52  66  41  63 /  10  20  10   5
CHANUTE         51  64  40  62 /  10  20  10   5
IOLA            50  64  40  62 /  20  20  10   5

&&

.ICT WATCHES/WARNINGS/ADVISORIES...NONE.

&&

JAKUB

Hazardous weather outlook, Apr 21, 4:00 PM CDT, 2 hours 19 minutes before

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE WICHITA KS
400 PM CDT THU APR 21 2005

KSZ032-033-047>053-067>072-082-083-091>096-098>100-221200-
RUSSELL-LINCOLN-BARTON-ELLSWORTH-SALINE-RICE-MCPHERSON-MARION-CHASE-
RENO-HARVEY-BUTLER-GREENWOOD-WOODSON-ALLEN-KINGMAN-SEDGWICK-HARPER-
SUMNER-COWLEY-ELK-WILSON-NEOSHO-CHAUTAUQUA-MONTGOMERY-LABETTE-
400 PM CDT THU APR 21 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND SOUTHEAST KANSAS.

.DAY ONE...LATE THIS AFTERNOON AND TONIGHT

A FEW SEVERE THUNDERSTORMS ARE POSSIBLE LATE THIS AFTERNOON AND
EARLY THIS EVENING ACROSS SOUTHEASTERN KANSAS. THE AREA OF CONCERN
IS EAST OF A LINE FROM EUREKA TO CEDARVALE. ISOLATED SUPERCELL
THUNDERSTORMS ARE POSSIBLE WITH THE PRIMARY THREATS OF VERY LARGE
HAIL AND DAMAGING WINDS. IN ADDITION, THERE WILL BE A LOWER END
THREAT FOR A TORNADO. THE STORMS SHOULD MOVE OUT OF EXTREME
SOUTHEAST KANSAS BETWEEN 7 PM AND 9 PM.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THE COMBINATION OF MOSTLY CLEAR SKIES, LIGHT WINDS AND DRY AIR WILL
RESULT IN A CHILLY FRIDAY NIGHT.  SOME FROST IS WITHIN THE REALM OF
POSSIBILITY IN PROTECTED AREAS NORTHWEST OF A LINE FROM SALINA TO
GREAT BEND EARLY SATURDAY MORNING.

THUNDERSTORMS ARE FORECAST FROM SUNDAY NIGHT THROUGH MONDAY NIGHT.
IT IS TOO EARLY TO SPECULATE WHETHER THESE WOULD BE SEVERE.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION IS POSSIBLE EAST OF A LINE, FROM EUREKA
TO CEDARVALE.

&&

FOR A GRAPHICAL VERSION OF THIS INFORMATION, SEE OUR
WEBPAGE AT (LOWERCASE) HTTP://WEATHER.GOV/WICHITA/HWO/HWOICT.HTM

HOWERTON/JMC

In the hours before

Special weather statement, Apr 21, 5:46 PM CDT, 33 minutes before

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The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Springfield, MO (KSGF), 12:00Z

11.3 hours before the tornado, 135 km from the path. April 21, 2005.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.

Mixed-layer CAPE: 780 J/kg
Mixed-layer CIN: -135 J/kg
Surface CAPE: 596 J/kg
Mixed-layer LCL: 696 m above ground
0-6 km bulk shear: 15 kt
0-1 km bulk shear: 18 kt
0-1 km storm-relative helicity: 118 m²/s²
0-3 km storm-relative helicity: 93 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0
0-3 km lapse rate: 5.2 K/km

Open this sounding in Storm Lab

Springfield, MO (KSGF), 00:00Z

0.7 hours after it, 135 km from the path. April 22, 2005.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.

Hodograph

Mixed-layer CAPE: 1218 J/kg
Mixed-layer CIN: -48 J/kg
Surface CAPE: 2031 J/kg
Mixed-layer LCL: 1229 m above ground
0-6 km bulk shear: 41 kt
0-1 km bulk shear: 11 kt
0-1 km storm-relative helicity: 81 m²/s²
0-3 km storm-relative helicity: 150 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 3.4
0-3 km lapse rate: 7.1 K/km

Open this sounding in Storm Lab

The surface observations

Parsons (PPF), 33 km from the path, in the two hours either side.

Time (UTC)	Temp (°F)	Dew point (°F)	Wind	Gust (kt)	Pressure (mb)	Weather
00:00 UTC

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Tulsa radar (KINX), 146 km away, was scanning. The volume nearest the touchdown began at 23:18 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

This ground now

The live radar over the track Every 2005 tornado in Kansas Every tornado in Kansas since 1950 Warnings in force in Kansas now The forecast where you are

The other tornadoes of April 21, 2005

11 more were confirmed in the United States that day.

Date	Time	Rating	Where	Path (mi)	Width (yd)	Damage
April 21	3:48 PM CDT	F0	Nemaha, KS	0.1	25
April 21	4:19 PM CDT	F0	Crawford, KS	0.2	50
April 21	5:04 PM CDT	F0	Atchison, KS	0.5	50
April 21	5:10 PM CDT	F0	Atchison, KS	2.0	50
April 21	5:54 PM CDT	F3	Neosho, KS	5.0	200	$200,000
April 21	6:05 PM CDT	F0	Cherokee, KS	0.1	20
April 21	6:34 PM CDT	F0	Labette, KS	0.5	55
April 21	6:53 PM CDT	F0	Tom Green, TX	0.5	30
April 21	7:48 PM CDT	F0	Rogers, OK	0.1	30
April 21	7:50 PM CDT	F0	Jackson, MO	2.0	50
April 21	8:30 PM CDT	F0	Wagoner, OK	0.1	30

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.