Alert archive / South Dakota / Tornado Warnings in 2017

Tornado Warning 40, NWS Sioux Falls, SD

September 19, 20174 counties in South Dakota

NWS Sioux Falls, SD issued this tornado warning at Sep 19, 2017, 11:04 PM CDT for 4 counties in South Dakota. It was in force for 26 min. 1 report 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
Sep 19, 2017, 11:04 PM CDT (04:04 UTC)
Expired
Sep 19, 2017, 11:30 PM CDT
In force
26 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Lake County, SD, McCook County, SD, Minnehaha County, SD, Moody County, SD

The radar

The Sioux Falls radar (KFSD), 31 km from the middle of the area, began a volume at 04:03 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.

What was reported inside it

TimeReportWhereRemark
Sep 19, 11:27 PM CDTTSTM WND DMGDell Rapids, SDTREE SNAPPED IN DELL RAPIDS...REPORT VIA SOCIAL MEDIA.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

IssuedProductOfficeLasted
Sep 19, 3:37 PM CDTTornado WatchSPC8 hr
Sep 19, 10:36 PM CDTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 4.1 hours before the alert went out and 167 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, Aberdeen, SD at 00:00Z on 2017-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2563 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, Aberdeen, SD at 00:00Z on 2017-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 229 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
2563 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
1127 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
229 m²/s²
0-3 km storm-relative helicity
239 m²/s²
Significant tornado parameter
2.6
Supercell composite
16.8

Open this sounding in Storm Lab

The text

As transmitted.

302 
WFUS53 KFSD 200404
TORFSD
SDC079-087-099-101-200430-
/O.NEW.KFSD.TO.W.0040.170920T0404Z-170920T0430Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
1104 PM CDT TUE SEP 19 2017

The National Weather Service in Sioux Falls has issued a

* Tornado Warning for...
  Southwestern Moody County in east central South Dakota...
  Southeastern Lake County in east central South Dakota...
  Northern Minnehaha County in southeastern South Dakota...
  Northeastern McCook County in southeastern South Dakota...

* Until 1130 PM CDT
    
* At 1104 PM CDT, a severe thunderstorm capable of producing a
  tornado was located near Montrose, or 10 miles north of Lake
  Vermillion State Recreation Area, moving east at 50 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...
  Colton and Chester around 1120 PM CDT. 
  Dell Rapids and Baltic around 1130 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.

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 4370 9717 4386 9725 4397 9671 4377 9659
TIME...MOT...LOC 0404Z 255DEG 44KT 4375 9715 

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

$$

Hanko
2 follow-up statements
587 
WWUS53 KFSD 200413
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
1113 PM CDT TUE SEP 19 2017

SDC087-200423-
/O.CAN.KFSD.TO.W.0040.000000T0000Z-170920T0430Z/
McCook SD-
1113 PM CDT TUE SEP 19 2017

...THE TORNADO WARNING FOR NORTHEASTERN MCCOOK COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

A tornado watch remains in effect until midnight CDT for east central
South Dakota.

A severe thunderstorm watch remains in effect until 500 AM CDT for
southeastern and east central South Dakota.

LAT...LON 4372 9704 4385 9709 4397 9671 4377 9659
TIME...MOT...LOC 0413Z 255DEG 44KT 4378 9700 

$$

SDC079-099-101-200430-
/O.CON.KFSD.TO.W.0040.000000T0000Z-170920T0430Z/
Moody SD-Lake SD-Minnehaha SD-
1113 PM CDT TUE SEP 19 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1130 PM CDT FOR
SOUTHWESTERN MOODY...SOUTHEASTERN LAKE AND NORTHERN MINNEHAHA
COUNTIES...
    
At 1113 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Colton, or 15 miles northeast of Lake Vermillion
State Recreation Area, moving east at 50 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...
  Dell Rapids and Baltic around 1130 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.

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 4372 9704 4385 9709 4397 9671 4377 9659
TIME...MOT...LOC 0413Z 255DEG 44KT 4378 9700 

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

$$

Hanko
609 
WWUS53 KFSD 200423
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
1123 PM CDT TUE SEP 19 2017

SDC079-099-101-200433-
/O.EXP.KFSD.TO.W.0040.000000T0000Z-170920T0430Z/
Moody SD-Lake SD-Minnehaha SD-
1123 PM CDT TUE SEP 19 2017

...THE TORNADO WARNING FOR SOUTHWESTERN MOODY...SOUTHEASTERN LAKE AND
NORTHERN MINNEHAHA COUNTIES WILL EXPIRE AT 1130 PM CDT...
    
The tornado threat has diminished and the Tornado Warning has been
cancelled. However, large hail and damaging winds remain likely and a
Severe Thunderstorm Warning remains in effect for the area.

A tornado watch remains in effect until midnight CDT for east central
South Dakota.

A severe thunderstorm watch remains in effect until 500 AM CDT for
southeastern and east central South Dakota.

LAT...LON 4372 9704 4385 9709 4397 9671 4377 9659
TIME...MOT...LOC 0423Z 255DEG 44KT 4381 9684 

$$

Hanko

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 19, 7:59 PM CDTSevere Thunderstorm WarningFSDBeadle31 min
Sep 19, 8:08 PM CDTTornado WarningFSDBeadle22 min
Sep 19, 8:38 PM CDTSevere Thunderstorm WarningFSDAurora, Beadle, Jerauld, Sanborn52 min
Sep 19, 8:53 PM CDTSevere Thunderstorm WarningFSDAurora, Brule52 min
Sep 19, 8:57 PM CDTSevere Thunderstorm WarningFSDGregory48 min
Sep 19, 9:17 PM CDTTornado WarningFSDAurora, Brule28 min
Sep 19, 9:21 PM CDTSevere Thunderstorm WarningFSDBeadle, Jerauld, Kingsbury, Miner, Sanborn39 min
Sep 19, 9:41 PM CDTSevere Thunderstorm WarningFSDAurora, Davison, Hanson, Sanborn49 min
Sep 19, 9:55 PM CDTSevere Thunderstorm WarningFSDBeadle, Kingsbury, Miner, Sanborn46 min
Sep 19, 10:00 PM CDTSevere Thunderstorm WarningFSDAurora, Davison, Douglas, Hanson, Hutchinson45 min
Sep 19, 10:15 PM CDTSevere Thunderstorm WarningFSDKingsbury, Lake, Miner, Sanborn45 min
Sep 19, 10:39 PM CDTSevere Thunderstorm WarningFSDHanson, Kingsbury, Lake, McCook, Miner, Minnehaha and 1 more36 min
Sep 19, 11:08 PM CDTSevere Thunderstorm WarningFSDBrookings, Lake, McCook, Minnehaha, Moody52 min
Sep 19, 11:29 PM CDTSevere Thunderstorm WarningFSDLincoln, Minnehaha46 min
Sep 19, 11:47 PM CDTSevere Thunderstorm WarningFSDBrookings43 min

Nearby

Tornado Warnings in South Dakota, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.