Alert archive / Iowa / Tornado Warnings in 2023

Tornado Warning 2, NWS Sioux Falls, SD

May 12, 2023Woodbury County, Iowa; Dakota County, Nebraska

NWS Sioux Falls, SD issued this tornado warning at May 12, 2023, 7:55 PM CDT for Woodbury County, Iowa; Dakota County, Nebraska. It was in force for 35 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
May 12, 2023, 7:55 PM CDT (00:55 UTC)
Expired
May 12, 2023, 8:30 PM CDT
In force
35 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Woodbury County, IA, Dakota County, NE

The radar

The Omaha radar (KOAX), 111 km from the middle of the area, began a volume at 00:58 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
May 12, 1:09 PM CDTTornado WatchSPC8 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 0.9 hours before the alert went out and 111 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 2023-05-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1363 joules per kilogram.LCLEL10008507005003002001001 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 2023-05-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 156 square meters per square second.19395878Sfc1 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
1363 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
1536 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
156 m²/s²
0-3 km storm-relative helicity
331 m²/s²
Significant tornado parameter
0.6
Supercell composite
8.4

Open this sounding in Storm Lab

The text

As transmitted.

892 
WFUS53 KFSD 130055
TORFSD
IAC193-NEC043-130130-
/O.NEW.KFSD.TO.W.0002.230513T0055Z-230513T0130Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
755 PM CDT Fri May 12 2023

The National Weather Service in Sioux Falls has issued a

* Tornado Warning for...
  Southwestern Woodbury County in west central Iowa...
  Eastern Dakota County in northeastern Nebraska...

* Until 830 PM CDT.
    
* At 755 PM CDT, a severe thunderstorm capable of producing a tornado
  was located over Salix, or 13 miles south of Sioux City, moving
  north at 25 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This dangerous storm will be near...
  Sergeant Bluff around 810 PM CDT.
  Dakota City around 815 PM CDT.
  Sioux City and South Sioux City around 820 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4226 9633 4228 9635 4228 9639 4247 9650
      4249 9622 4226 9628 4225 9633
TIME...MOT...LOC 0055Z 170DEG 24KT 4231 9633 

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

$$

SST
2 follow-up statements
879 
WWUS53 KFSD 130112
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
812 PM CDT Fri May 12 2023

IAC193-NEC043-130130-
/O.CON.KFSD.TO.W.0002.000000T0000Z-230513T0130Z/
Woodbury IA-Dakota NE-
812 PM CDT Fri May 12 2023

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 830 PM CDT FOR WEST
CENTRAL WOODBURY AND NORTHEASTERN DAKOTA COUNTIES...
    
At 812 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Sergeant Bluff, or near Sioux City, moving north at
30 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

Locations impacted include...
  Sioux City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4235 9637 4247 9646 4249 9622 4236 9627
TIME...MOT...LOC 0112Z 170DEG 24KT 4243 9636 

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

$$

SST
126 
WWUS53 KFSD 130124
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
824 PM CDT Fri May 12 2023

IAC193-NEC043-130134-
/O.EXP.KFSD.TO.W.0002.000000T0000Z-230513T0130Z/
Woodbury IA-Dakota NE-
824 PM CDT Fri May 12 2023

...THE TORNADO WARNING FOR WEST CENTRAL WOODBURY AND NORTHEASTERN
DAKOTA COUNTIES WILL EXPIRE AT 830 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with this thunderstorm.

A Tornado Watch remains in effect until 900 PM CDT for west central
Iowa...and northeastern Nebraska.

LAT...LON 4235 9637 4247 9646 4249 9622 4236 9627
TIME...MOT...LOC 0124Z 170DEG 24KT 4250 9638 

$$

SST

The office that day

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

IssuedProductOfficeCountiesLasted
May 12, 7:27 PM CDTSevere Thunderstorm WarningFSDWoodbury33 min
May 12, 7:46 PM CDTSevere Thunderstorm WarningFSDPlymouth, Woodbury44 min
May 12, 7:50 PM CDTSevere Thunderstorm WarningFSDWoodbury40 min
May 12, 8:16 PM CDTTornado WarningFSDPlymouth, Woodbury29 min
May 12, 8:17 PM CDTSevere Thunderstorm WarningFSDPlymouth, Sioux28 min
May 12, 8:27 PM CDTSevere Thunderstorm WarningFSDPlymouth, Woodbury48 min
May 13, 11:02 AM CDTRiver Flood WarningFSDDickinson7 days
May 13, 1:48 PM CDTTornado WarningFSDBuena Vista27 min
May 13, 4:25 PM CDTTornado Warning Tornado observedFSDBuena Vista35 min
May 13, 4:36 PM CDTTornado WarningFSDBuena Vista24 min
May 12, 7:09 PM CDTSevere Thunderstorm Warning Considerable damage threatFSDDixon51 min

Nearby

Tornado Warnings in Iowa, 2023Tornado Warnings in Nebraska, 2023Every tornado warning in 2023Tornadoes in 2023

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.