Alert archive / Iowa / Tornado Watches in 2001

Tornado Watch 793

October 22, 200120 counties in Iowa; 20 counties in Missouri

The Storm Prediction Center issued this tornado watch at Oct 22, 2001, 4:00 PM CDT for 20 counties in Iowa; 20 counties in Missouri. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Oct 22, 2001, 4:00 PM CDT (21:00 UTC)
Expired: Oct 22, 2001, 9:00 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 40 counties

Appanoose County, IA, Clarke County, IA, Davis County, IA, Decatur County, IA, Des Moines County, IA, Henry County, IA, Jefferson County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Lucas County, IA, Mahaska County, IA, Marion County, IA, Monroe County, IA, Muscatine County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Adair County, MO, Caldwell County, MO, Clark County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Knox County, MO, Lewis County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Mercer County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Shelby County, MO, Sullivan County, MO

The radar

The Des Moines radar (KDMX), 158 km from the middle of the area, began a volume at 21:03 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Warnings issued inside it

5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Oct 22, 4:34 PM CDT	Severe Thunderstorm Warning	DMX	Wapello	41 min
Oct 22, 5:00 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose	35 min
Oct 22, 5:08 PM CDT	Severe Thunderstorm Warning	DVN	Jefferson	37 min
Oct 22, 5:19 PM CDT	Severe Thunderstorm Warning	DMX	Davis	41 min
Oct 22, 5:49 PM CDT	Severe Thunderstorm Warning	DVN	Van Buren	56 min

The nearest sounding before it

Topeka, KS (KTOP), launched 12:00Z, 9.0 hours before the alert went out and 261 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

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.

Mixed-layer CAPE: 228 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 715 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 246 m²/s²
0-3 km storm-relative helicity: 260 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

645 
WWUS9 KMKC 222041
SEL3  

SEL3  
MKC WW 222035
IAZ000-MOZ000-230200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 793
STORM PREDICTION CENTER NORMAN OK
335 PM CDT MON OCT 22 2001

THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

   SOUTH CENTRAL AND SOUTHEAST IOWA                               
   NORTHERN MISSOURI                           

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 400 PM UNTIL 900
PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 75 STATUTE MILES EAST AND WEST
OF A LINE FROM 50 MILES SOUTH SOUTHEAST OF SPICKARD MISSOURI TO 35
MILES NORTH NORTHEAST OF OTTUMWA IOWA.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES SEVERE
THUNDERSTORM WATCH NUMBER 792.  WATCH NUMBER 792 WILL NOT BE IN
EFFECT AFTER 400 PM CDT.

DISCUSSION...SEVERE STORM OVER SRN IA IS STARTING TO SHOW SUPERCELL
CHARACTERISTICS...WHILE NEW CONVECTION IS SLOWLY INCREASING ACROSS
NWRN MO.  STORMS ARE EXPECTED TO TRACK EWD/ENEWD NEAR THE WARM
FRONT THAT EXTENDS ALONG THE MO/IA BORDER.  SHORT WAVE TROUGH
MOVING INTO WRN IA WILL AID DYNAMIC FORCING FOR UPWARD MOTION.  VAD
AND PROFILER DATA SHOW STRENGTHENING SOUTHERLY LOW LEVEL WINDS THAT
VEER AND INCREASE WITH HEIGHT PROVIDING A FAVORABLE ENVIRONMENT FOR
SUPERCELLS AND POSSIBLE TORNADOES.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. 
MEAN STORM MOTION VECTOR 25035.


...WEISS

413,0904 393,0915 393,0944 413,0933

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 22, 12:30 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Adams, Audubon, Boone, Carroll, Cass and 23 more	6 hr
Oct 22, 6:30 PM CDT	Severe Thunderstorm Watch	SPC	Scott	5 hr

Nearby

Tornado Watches in Iowa, 2001 Tornado Watches in Missouri, 2001 Every tornado watch in 2001

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.