Alert archive / Iowa / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 9, NWS Sioux Falls, SD

April 7, 2001Lyon County, O'Brien County, Osceola County, Iowa; Nobles County, Rock County, Minnesota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Apr 7, 2001, 3:05 AM CDT for Lyon County, O'Brien County, Osceola County, Iowa; Nobles County, Rock County, Minnesota. It was in force for 25 min. 4 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Apr 7, 2001, 3:05 AM CDT (08:05 UTC)
Expired
Apr 7, 2001, 3:30 AM CDT
In force
25 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

Counties Lyon County, IA, O'Brien County, IA, Osceola County, IA, Nobles County, MN, Rock County, MN

The radar

The Sioux Falls radar (KFSD), 69 km from the middle of the area, began a volume at 08:04 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

TimeReportWhereRemark
Apr 7, 3:15 AM CDTThunderstorm Wind 52 ELittle Rock, IA
Apr 7, 3:25 AM CDTThunderstorm Wind 52 ESibley, IA
Apr 7, 3:25 AM CDTThunderstorm Wind 52 ESheldon, IA
Apr 7, 3:29 AM CDTThunderstorm Wind 52 EAdrian, MN

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.

IssuedProductOfficeLasted
Apr 7, 1:45 AM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 8.1 hours before the alert went out and 239 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, Omaha, NE at 00:00Z on 2001-04-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 770 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2001-04-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 205 square meters per square second.1939587897Sfc1 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
770 J/kg
Mixed-layer CIN
-60 J/kg
Mixed-layer LCL
454 m above ground
0-6 km bulk shear
78 kt
0-1 km storm-relative helicity
205 m²/s²
0-3 km storm-relative helicity
278 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.9

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KFSD 070805 RRA
SVRFSD
IAC119-141-143-MNC105-133-070830-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
305 AM CDT SAT APR 7 2001

THE NATIONAL WEATHER SERVICE

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 7, 2:11 AM CDTSevere Thunderstorm WarningFSDPlymouth, Woodbury34 min
Apr 7, 2:22 AM CDTSevere Thunderstorm WarningFSDLyon, Sioux38 min
Apr 7, 3:29 AM CDTSevere Thunderstorm WarningFSDNobles31 min
Apr 7, 3:51 AM CDTTornado WarningFSDMurray, Nobles24 min
Apr 7, 4:23 AM CDTSevere Thunderstorm WarningFSDMurray37 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2001Severe Thunderstorm Warnings in Minnesota, 2001Every severe thunderstorm warning 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.