Alert archive / Iowa / Tornado Warnings in 2013

Tornado Warning 24, NWS Sioux Falls, SD

October 4, 2013Clay County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Oct 4, 2013, 8:55 PM CDT for Clay County, Iowa. It was in force for 20 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Oct 4, 2013, 8:55 PM CDT (01:55 UTC)
Expired
Oct 4, 2013, 9:15 PM CDT
In force
20 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

County Clay County, IA

The radar

The Sioux Falls radar (KFSD), 155 km from the middle of the area, began a volume at 01:58 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Oct 4, 2:38 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 1.9 hours before the alert went out and 223 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 2013-10-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1572 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, Omaha, NE at 00:00Z on 2013-10-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 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
1572 J/kg
Mixed-layer CIN
-22 J/kg
Mixed-layer LCL
1464 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
224 m²/s²
Significant tornado parameter
0.4
Supercell composite
5.7

Open this sounding in Storm Lab

The text

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

497 
WFUS53 KFSD 050155
TORFSD
IAC041-050215-
/O.NEW.KFSD.TO.W.0024.131005T0155Z-131005T0215Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
855 PM CDT FRI OCT 4 2013

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  EAST CENTRAL CLAY COUNTY IN NORTHWEST IOWA...

* UNTIL 915 PM CDT

* AT 855 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A
  TORNADO WAS LOCATED 6 MILES NORTH OF WEBB...AND MOVING NORTHEAST AT
  40 MPH.

  HAZARD...TORNADO.

  SOURCE...RADAR INDICATED ROTATION.

  IMPACT...MOBILE HOMES WILL BE DAMAGED OR DESTROYED. DAMAGE TO
           ROOFS...WINDOWS AND VEHICLES WILL OCCUR. FLYING DEBRIS
           WILL BE DEADLY TO PEOPLE AND ANIMALS. TREE DAMAGE IS
           LIKELY.

* THIS DANGEROUS STORM WILL AFFECT MAINLY RURAL AREAS OF EAST CENTRAL
  CLAY COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORNADOES ARE DIFFICULT TO SEE AND CONFIRM AT NIGHT. TAKE COVER NOW.

&&

LAT...LON 4294 9498 4299 9512 4320 9493 4319 9490
      4298 9491
TIME...MOT...LOC 0156Z 214DEG 35KT 4304 9498

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

CHAPMAN
2 follow-up statements
176 
WWUS53 KFSD 050207
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
907 PM CDT FRI OCT 4 2013

IAC041-050215-
/O.CON.KFSD.TO.W.0024.000000T0000Z-131005T0215Z/
CLAY IA-
907 PM CDT FRI OCT 4 2013

...A TORNADO WARNING REMAINS IN EFFECT FOR EAST CENTRAL CLAY COUNTY
UNTIL 915 PM CDT...

AT 905 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A BRIEF
SPINUP TORNADO WAS LOCATED 12 MILES EAST OF SPENCER...AND MOVING 
NORTHEAST AT 40 MPH.

HAZARD...TORNADO.

SOURCE...RADAR INDICATED ROTATION.

IMPACT...MOBILE HOMES WILL BE DAMAGED OR DESTROYED. DAMAGE TO
         ROOFS...WINDOWS AND VEHICLES WILL OCCUR. FLYING DEBRIS WILL
         BE DEADLY TO PEOPLE AND ANIMALS. TREE DAMAGE IS LIKELY.

LOCATIONS IMPACTED INCLUDE...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS LINE OF THUNDERSTORMS IS CAPABLE OF PRODUCING TORNADOES AND
WIDESPREAD SIGNIFICANT WIND DAMAGE. DO NOT WAIT TO SEE OR HEAR THE
TORNADO. FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST
FLOOR OF YOUR HOME OR BUSINESS.

&&

LAT...LON 4294 9498 4299 9512 4320 9493 4319 9490
      4298 9491
TIME...MOT...LOC 0207Z 214DEG 35KT 4313 9490

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

CHAPMAN
033 
WWUS53 KFSD 050212 RRA
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
912 PM CDT FRI OCT 4 2013

IAC041-050223-
/O.EXP.KFSD.TO.W.0024.000000T0000Z-131005T0215Z/
CLAY IA-
912 PM CDT FRI OCT 4 2013

...THE TORNADO WARNING FOR EAST CENTRAL CLAY COUNTY WILL EXPIRE AT
915 PM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED
AREA.

LAT...LON 4294 9498 4299 9512 4320 9493 4319 9490
      4298 9491
TIME...MOT...LOC 0213Z 214DEG 35KT 4318 9485

$$

CHAPMAN

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 4, 7:22 PM CDTTornado Warning EmergencyFSDCherokee38 min
Oct 4, 7:25 PM CDTTornado Warning Tornado observedFSDPlymouth35 min
Oct 4, 7:54 PM CDTTornado WarningFSDBuena Vista, Cherokee36 min
Oct 4, 8:27 PM CDTTornado WarningFSDBuena Vista, Clay33 min
Oct 4, 8:33 PM CDTSevere Thunderstorm WarningFSDBuena Vista42 min

Nearby

Tornado Warnings in Iowa, 2013Every tornado warning in 2013Tornadoes in 2013

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.