Alert archive / Iowa / Tornado Warnings in 2017

Tornado Warning 7, NWS Sioux Falls, SD

May 17, 2017Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at May 17, 2017, 2:03 PM CDT for Sioux County, Iowa. It was in force for 27 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 17, 2017, 2:03 PM CDT (19:03 UTC)
Expired
May 17, 2017, 2:30 PM CDT
In force
27 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

County Sioux County, IA

The radar

The Sioux Falls radar (KFSD), 78 km from the middle of the area, began a volume at 19:03 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 17, 12:08 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 7.1 hours before the alert went out and 190 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 12:00Z on 2017-05-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 121 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 12:00Z on 2017-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 119 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
121 J/kg
Mixed-layer CIN
-156 J/kg
Mixed-layer LCL
1106 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
119 m²/s²
0-3 km storm-relative helicity
132 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

243 
WFUS53 KFSD 171903
TORFSD
IAC167-171930-
/O.NEW.KFSD.TO.W.0007.170517T1903Z-170517T1930Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
203 PM CDT WED MAY 17 2017

The National Weather Service in Sioux Falls has issued a

* Tornado Warning for...
  Central Sioux County in northwestern Iowa...

* Until 230 PM CDT
    
* At 203 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Maurice, or near Orange City, moving northwest 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. 

* This dangerous storm will be near...
  Maurice around 210 PM CDT. 
  Sioux Center around 230 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 4294 9600 4291 9615 4313 9637 4320 9621
TIME...MOT...LOC 1903Z 153DEG 24KT 4294 9610 

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

$$

Ferguson
1 follow-up statement
389 
WWUS53 KFSD 171915
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
215 PM CDT WED MAY 17 2017

IAC167-171930-
/O.CON.KFSD.TO.W.0007.000000T0000Z-170517T1930Z/
Sioux IA-
215 PM CDT WED MAY 17 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 230 PM CDT FOR CENTRAL
SIOUX COUNTY...
    
At 215 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Maurice, or near Orange City, moving northwest 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...
  Sioux Center around 230 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 4297 9602 4295 9615 4313 9637 4320 9621
TIME...MOT...LOC 1915Z 154DEG 20KT 4300 9613 

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

$$

Ferguson

The office that day

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

IssuedProductOfficeCountiesLasted
May 16, 7:43 PM CDTSevere Thunderstorm WarningFSDIda33 min
May 16, 8:22 PM CDTSevere Thunderstorm WarningFSDBuena Vista23 min
May 17, 11:16 AM CDTRiver Flood WarningFSDClay24 hr
May 17, 11:16 AM CDTRiver Flood WarningFSDBuena Vista, Clay24 hr
May 17, 11:16 AM CDTRiver Flood WarningFSDPlymouth, Sioux5 days
May 17, 11:16 AM CDTRiver Flood WarningFSDPlymouth6 days
May 17, 11:16 AM CDTRiver Flood WarningFSDClay4 days
May 17, 11:16 AM CDTRiver Flood WarningFSDClay, Dickinson59 hr
May 17, 1:33 PM CDTTornado WarningFSDSioux27 min
May 17, 1:56 PM CDTTornado WarningFSDSioux34 min
May 17, 2:28 PM CDTTornado WarningFSDLyon, Sioux32 min
May 17, 2:34 PM CDTSevere Thunderstorm WarningFSDLyon26 min
May 17, 3:01 PM CDTTornado WarningFSDLyon29 min

Nearby

Tornado Warnings in Iowa, 2017Every tornado warning in 2017Tornadoes in 2017

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.