Alert archive / Iowa / Tornado Watches in 2000
Tornado Watch 266
The Storm Prediction Center issued this tornado watch at May 11, 2000, 10:30 PM CDT for 12 counties in Illinois; 19 counties in Iowa; 14 counties in Wisconsin. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- May 11, 2000, 10:30 PM CDT (03:30 UTC)
- Expired
- May 12, 2000, 4:00 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
All 45 counties
Benton County, IA, Buchanan County, IA, Cedar County, IA, Clinton County, IA, Delaware County, IA, Dubuque County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Boone County, IL, Carroll County, IL, DeKalb County, IL, Jo Daviess County, IL, Lee County, IL, McHenry County, IL, Mercer County, IL, Ogle County, IL, Rock Island County, IL, Stephenson County, IL, Whiteside County, IL, Winnebago County, IL, Dane County, WI, Dodge County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Ozaukee County, WI, Rock County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI
The radar
The Quad Cities radar (KDVN), 76 km from the middle of the area, began a volume at 03:31 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
11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 11, 10:42 PM CDT | Severe Thunderstorm Warning | DVN | Dubuque | 48 min |
| May 11, 10:54 PM CDT | Severe Thunderstorm Warning | MKX | Columbia, Dane, Dodge | 66 min |
| May 11, 11:11 PM CDT | Severe Thunderstorm Warning | MKX | Jefferson | 64 min |
| May 11, 11:11 PM CDT | Severe Thunderstorm Warning | MKX | Washington | 64 min |
| May 11, 11:22 PM CDT | Severe Thunderstorm Warning | MKX | Waukesha | 53 min |
| May 11, 11:35 PM CDT | Severe Thunderstorm Warning | MKX | Milwaukee, Ozaukee | 55 min |
| May 11, 11:55 PM CDT | Severe Thunderstorm Warning | MKX | Jefferson | 65 min |
| May 12, 12:02 AM CDT | Severe Thunderstorm Warning | MKX | Waukesha | 58 min |
| May 12, 12:21 AM CDT | Severe Thunderstorm Warning | MKX | Milwaukee | 69 min |
| May 12, 12:44 AM CDT | Severe Thunderstorm Warning | MKX | Kenosha, Racine | 61 min |
| May 12, 12:56 AM CDT | Severe Thunderstorm Warning | DVN | Benton | 49 min |
The nearest sounding before it
Davenport, (KDVN), launched 00:00Z, 3.5 hours before the alert went out and 74 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.
- Mixed-layer CAPE
- 2323 J/kg
- Mixed-layer CIN
- -39 J/kg
- Mixed-layer LCL
- 1261 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 171 m²/s²
- 0-3 km storm-relative helicity
- 218 m²/s²
- Significant tornado parameter
- 1.8
- Supercell composite
- 13.9
The text
As transmitted, in the capitals the NWS used until 2016.
410 WWUS9 KMKC 120305 SEL6 SEL6 MKC WW 120301 IAZ000-ILZ000-WIZ000-120900- URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 266 STORM PREDICTION CENTER NORMAN OK 1001 PM CDT THU MAY 11 2000 THE STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF EASTERN IOWA NORTHERN ILLINOIS SOUTHERN WISCONSIN EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 1030 PM UNTIL 400 AM CDT. TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE TORNADO WATCH AREA IS ALONG AND 60 STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES SOUTHWEST OF CEDAR RAPIDS IOWA TO 10 MILES NORTH NORTHEAST OF MILWAUKEE WISCONSIN. 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 TORNADO WATCH NUMBER 264. WATCH NUMBER 264 WILL NOT BE IN EFFECT AFTER 1030 PM CDT. CONTINUE...WW 265... DISCUSSION...WITH FAVORABLE VEERING SHEAR PROFILES E OF SURFACE LOW AND CONTINUED INFLUX OF VERY UNSTABLE AIRMASS...THE SUPERCELLS NOW MOVING ACROSS ERN IA INTO SWRN WI WILL CONTINUE TO DEVELOP E/SE. STILL POTENTIAL FOR ISOLATED TORNADOES ALONG WITH LARGE HAIL/DAMAGING WINDS. AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM MOTION VECTOR 25030. ...HALES 421,0874 403,0921 422,0921 435,0874
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 12, 2:00 PM CDT | Tornado Watch | SPC | Cass, Champaign, Christian, Coles, Cook, Cumberland and 28 more | 6 hr |
| May 12, 4:30 PM CDT | Severe Thunderstorm Watch | SPC | Bond, Calhoun, Clinton, Effingham, Fayette, Jersey and 6 more | 6 hr |
| May 12, 6:30 PM CDT | Tornado Watch | SPC | Clark, Clay, Crawford, Jasper, Lawrence, Richland | 6 hr |
| May 12, 2:00 AM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Appanoose, Audubon, Boone, Cass and 29 more | 5 hr |
| May 12, 2:30 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Brown, Calumet, Columbia, Dane, Dodge and 28 more | 6 hr |
Nearby
Tornado Watches in Iowa, 2000Tornado Watches in Wisconsin, 2000Tornado Watches in Illinois, 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.