Alert archive / Iowa / Severe Thunderstorm Warnings in 2002
Severe Thunderstorm Warning 270, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 11, 2002, 10:52 PM CDT for Lyon County, Iowa; Rock County, Minnesota. It was in force for 38 min. 2 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 11, 2002, 10:52 PM CDT (03:52 UTC)
- Expired
- Aug 11, 2002, 11:30 PM CDT
- In force
- 38 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Counties, with a storm outline in the text
Counties Lyon County, IA, Rock County, MN
The radar
The Sioux Falls radar (KFSD), 34 km from the middle of the area, began a volume at 03:56 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 11, 11:05 PM CDT | Hail 0.75 | Larchwood, IA | |
| Aug 11, 11:20 PM CDT | Thunderstorm Wind 52 E | Luverne, MN | Thunderstorm winds caused tree damage, including several branches down. |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 11, 9:55 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
The nearest sounding before it
Aberdeen, SD (KABR), launched 00:00Z, 3.9 hours before the alert went out and 220 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
- 2317 J/kg
- Mixed-layer CIN
- -146 J/kg
- Mixed-layer LCL
- 2063 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 115 m²/s²
- 0-3 km storm-relative helicity
- 92 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.5
The text
As transmitted, in the capitals the NWS used until 2016.
374 WUUS53 KFSD 120352 SVRFSD IAC119-MNC133-120430- BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE SIOUX FALLS SD 1052 PM CDT SUN AUG 11 2002 THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... LYON COUNTY IN NORTHWEST IOWA ROCK COUNTY IN SOUTHWEST MINNESOTA * UNTIL 1130 PM CDT * AT 1052 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS FROM 14 MILES WEST OF HARDWICK TO 20 MILES WEST OF LARCHWOOD...OR FROM 15 MILES SOUTHWEST OF PIPESTONE TO 12 MILES SOUTHWEST OF SIOUX FALLS...MOVING EAST AT 45 MPH. * SEVERE THUNDERSTORMS WILL BE NEAR... BEAVER CREEK AROUND 1105 PM CDT HARDWICK...HILLS...LARCHWOOD AROUND 1110 PM CDT LUVERNE...LESTER AROUND 1115 PM CDT INWOOD AROUND 1120 PM CDT ROCK RAPIDS...ALVORD AROUND 1125 PM CDT THIS STORM WILL PRODUCE DAMAGING WIND GUSTS TO 80 MPH. GO INSIDE A STURDY BUILDING AND STAY AWAY FROM WINDOWS. LAT...LON 4383 9642 4328 9653 4328 9608 4382 9608 BOUSTEAD
The office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 11, 11:14 PM CDT | Severe Thunderstorm Warning | FSD | Sioux | 46 min |
| Aug 11, 11:32 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, Osceola | 43 min |
| Aug 12, 12:09 AM CDT | Severe Thunderstorm Warning | FSD | Dickinson | 36 min |
| Aug 12, 12:40 AM CDT | Severe Thunderstorm Warning | FSD | Clay | 35 min |
| Aug 12, 1:08 AM CDT | Severe Thunderstorm Warning | FSD | Lyon | 37 min |
| Aug 12, 1:42 AM CDT | Severe Thunderstorm Warning | FSD | Sioux | 33 min |
| Aug 12, 1:43 AM CDT | Severe Thunderstorm Warning | FSD | Lyon | 32 min |
| Aug 12, 2:16 AM CDT | Severe Thunderstorm Warning | FSD | Sioux | 29 min |
| Aug 12, 2:21 AM CDT | Severe Thunderstorm Warning | FSD | O'Brien | 54 min |
| Aug 12, 2:25 AM CDT | Severe Thunderstorm Warning | FSD | Dickinson | 50 min |
| Aug 12, 2:57 AM CDT | Severe Thunderstorm Warning | FSD | Clay | 33 min |
| Aug 11, 10:59 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, Murray, Pipestone | 46 min |
| Aug 11, 11:13 PM CDT | Severe Thunderstorm Warning | FSD | Nobles | 32 min |
| Aug 11, 11:42 PM CDT | Severe Thunderstorm Warning | FSD | Cottonwood, Jackson | 48 min |
| Aug 11, 11:44 PM CDT | Severe Thunderstorm Warning | FSD | Nobles | 46 min |
| Aug 11, 11:46 PM CDT | Severe Thunderstorm Warning | FSD | Nobles | 14 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 2002Severe Thunderstorm Warnings in Minnesota, 2002Every severe thunderstorm warning in 2002
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.