Alert archive / Iowa / Tornado Watches in 2000

Tornado Watch 728

September 11, 20008 counties in Illinois; 27 counties in Iowa; Grant County, Iowa County, Lafayette County, Wisconsin

The Storm Prediction Center issued this tornado watch at Sep 11, 2000, 1:15 PM CDT for 8 counties in Illinois; 27 counties in Iowa; Grant County, Iowa County, Lafayette County, Wisconsin. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Sep 11, 2000, 1:15 PM CDT (18:15 UTC)
Expired
Sep 11, 2000, 7:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 38 counties

Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cedar County, IA, Chickasaw County, IA, Clayton County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Floyd County, IA, Grundy County, IA, Iowa County, IA, Jackson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Mahaska County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Washington County, IA, Carroll County, IL, Henry County, IL, Jo Daviess County, IL, Mercer County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Whiteside County, IL, Grant County, WI, Iowa County, WI, Lafayette County, WI

The radar

The Quad Cities radar (KDVN), 116 km from the middle of the area, began a volume at 18:18 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

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

IssuedProductOfficeCountiesLasted
Sep 11, 1:26 PM CDTSevere Thunderstorm WarningDVNCarroll, Whiteside49 min
Sep 11, 4:29 PM CDTSevere Thunderstorm WarningARXGrant61 min
Sep 11, 4:43 PM CDTSevere Thunderstorm WarningDVNDubuque32 min
Sep 11, 4:50 PM CDTSevere Thunderstorm WarningMKXIowa, Lafayette55 min
Sep 11, 5:02 PM CDTSevere Thunderstorm WarningDMXPoweshiek43 min
Sep 11, 5:05 PM CDTTornado WarningDVNDubuque25 min
Sep 11, 5:13 PM CDTTornado WarningARXGrant32 min
Sep 11, 5:14 PM CDTSevere Thunderstorm WarningDVNBenton, Iowa, Johnson, Linn46 min
Sep 11, 5:19 PM CDTSevere Thunderstorm WarningDVNJo Daviess41 min
Sep 11, 5:41 PM CDTSevere Thunderstorm WarningDVNKeokuk49 min
Sep 11, 5:41 PM CDTSevere Thunderstorm WarningARXGrant49 min
Sep 11, 5:45 PM CDTSevere Thunderstorm WarningMKXLafayette30 min
Sep 11, 5:46 PM CDTFlash Flood WarningMKXLafayette3 hr
Sep 11, 5:53 PM CDTSevere Thunderstorm WarningDVNDelaware, Dubuque, Jones67 min
Sep 11, 5:54 PM CDTSevere Thunderstorm WarningDVNBenton, Iowa, Johnson, Linn66 min
Sep 11, 6:01 PM CDTFlash Flood WarningARXGrant4 hr
Sep 11, 6:22 PM CDTSevere Thunderstorm WarningDVNKeokuk, Washington68 min
Sep 11, 6:23 PM CDTSevere Thunderstorm WarningDMXTama27 min
Sep 11, 6:37 PM CDTSevere Thunderstorm WarningDMXPoweshiek33 min
Sep 11, 6:45 PM CDTSevere Thunderstorm WarningDVNJo Daviess45 min
Sep 11, 6:45 PM CDTSevere Thunderstorm WarningDVNStephenson45 min
Sep 11, 6:57 PM CDTSevere Thunderstorm WarningDVNCedar, Clinton, Scott48 min

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 6.3 hours before the alert went out and 121 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-pSkew-T log-p diagram, Davenport, at 12:00Z on 2000-09-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1636 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2000-09-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 95 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1636 J/kg
Mixed-layer CIN
-239 J/kg
Mixed-layer LCL
1387 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
95 m²/s²
0-3 km storm-relative helicity
99 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

882 
WWUS9 KMKC 111758
SEL8  

SEL8  
MKC WW 111753
IAZ000-ILZ000-WIZ000-120000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 728
STORM PREDICTION CENTER NORMAN OK
1253 PM CDT MON SEP 11 2000

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

   EASTERN IOWA                               
   NORTHWEST ILLINOIS                           
   SOUTHWEST WISCONSIN                          

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 115 PM UNTIL 700
PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 70 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 40 MILES SOUTHWEST OF WATERLOO IOWA TO 60
MILES EAST SOUTHEAST OF DUBUQUE 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.


DISCUSSION...STORMS ARE DEVELOPING ALONG CONVECTIVE BOUNDARY ACROSS
E CENTRAL/NERN IA.  AIR MASS IS VERY UNSTABLE WITH SBCAPE ACROSS
SERN IA INTO IL TO 4000 J/KG.  VAD WIND PROFILES SHOW STORM
RELATIVE HELICITY AROUND 170 M2/S2 INDICATING FAVORABLE SHEAR FOR
TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. 
MEAN STORM MOTION VECTOR 26035.


...MCCARTHY

430,0925 430,0893 410,0893 410,0925

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 11, 1:30 PM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Cook, DeKalb, DuPage, Grundy and 9 more6 hr
Sep 10, 8:15 PM CDTSevere Thunderstorm WatchSPCAllamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 9 more6 hr
Sep 11, 3:30 PM CDTTornado WatchSPCAllamakee, Howard, Mitchell, Winneshiek5 hr
Sep 11, 4:45 PM CDTSevere Thunderstorm WatchSPCAppanoose, Clarke, Davis, Decatur, Henry, Jefferson and 8 more5 hr
Sep 11, 5:15 PM CDTSevere Thunderstorm WatchSPCAdams, Brown, Calumet, Columbia, Crawford, Dodge and 26 more6 hr

Nearby

Tornado Watches in Iowa, 2000Tornado Watches in Illinois, 2000Tornado Watches in Wisconsin, 2000Every tornado watch in 2000

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.