Alert archive / South Dakota / Tornado Warnings in 2017

Tornado Warning 39, NWS Sioux Falls, SD

September 19, 2017Aurora County, Brule County, South Dakota

NWS Sioux Falls, SD issued this tornado warning at Sep 19, 2017, 9:17 PM CDT for Aurora County, Brule County, South Dakota. It was in force for 28 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, 9:17 PM CDT (02:17 UTC)
Expired: Sep 19, 2017, 9:45 PM CDT
In force: 28 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.25 in

Counties Aurora County, SD, Brule County, SD

The radar

The Sioux Falls radar (KFSD), 158 km from the middle of the area, began a volume at 02:19 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

Time	Report	Where	Remark
Sep 19, 9:20 PM CDT	HAIL 1.5	White Lake, SD

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.

Issued	Product	Office	Lasted
Sep 19, 3:37 PM CDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 2.3 hours before the alert went out and 133 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

792 
WFUS53 KFSD 200217
TORFSD
SDC003-015-200245-
/O.NEW.KFSD.TO.W.0039.170920T0217Z-170920T0245Z/

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

The National Weather Service in Sioux Falls has issued a

* Tornado Warning for...
  Central Aurora County in south central South Dakota...
  East central Brule County in south central South Dakota...

* Until 945 PM CDT
    
* At 917 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near White Lake, or 11 miles southeast of Kimball,
  moving northeast at 35 mph.

  HAZARD...Tornado and half dollar size hail. 

  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...
  White Lake around 925 PM CDT. 
  Plankinton around 940 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 4369 9889 4394 9853 4369 9832 4358 9882
TIME...MOT...LOC 0217Z 241DEG 32KT 4365 9876 

TORNADO...RADAR INDICATED
HAIL...1.25IN

$$

Hanko

2 follow-up statements

874 
WWUS53 KFSD 200225
SVSFSD

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

SDC015-200235-
/O.CAN.KFSD.TO.W.0039.000000T0000Z-170920T0245Z/
Brule SD-
925 PM CDT TUE SEP 19 2017

...THE TORNADO WARNING FOR EAST CENTRAL BRULE 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 south
central and southeastern South Dakota.

LAT...LON 4375 9879 4393 9853 4369 9832 4362 9865
      4365 9878
TIME...MOT...LOC 0225Z 247DEG 26KT 4367 9869 

$$

SDC003-200245-
/O.CON.KFSD.TO.W.0039.000000T0000Z-170920T0245Z/
Aurora SD-
925 PM CDT TUE SEP 19 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 945 PM CDT FOR CENTRAL
AURORA COUNTY...
    
At 925 PM CDT, a severe thunderstorm capable of producing a tornado
was located near White Lake, or 10 miles west of Plankinton, moving
east at 30 mph.

HAZARD...Tornado and half dollar size hail. 

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...
  Plankinton around 945 PM CDT. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4375 9879 4393 9853 4369 9832 4362 9865
      4365 9878
TIME...MOT...LOC 0225Z 247DEG 26KT 4367 9869 

TORNADO...RADAR INDICATED
HAIL...1.25IN

$$

Hanko

861 
WWUS53 KFSD 200242
SVSFSD

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

SDC003-200252-
/O.EXP.KFSD.TO.W.0039.000000T0000Z-170920T0245Z/
Aurora SD-
942 PM CDT TUE SEP 19 2017

...THE TORNADO WARNING FOR CENTRAL AURORA COUNTY WILL EXPIRE AT 945
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 south
central and southeastern South Dakota.

LAT...LON 4375 9879 4393 9853 4369 9832 4362 9865
      4365 9878
TIME...MOT...LOC 0242Z 241DEG 32KT 4374 9852 

$$

Hanko

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 19, 7:59 PM CDT	Severe Thunderstorm Warning	FSD	Beadle	31 min
Sep 19, 8:08 PM CDT	Tornado Warning	FSD	Beadle	22 min
Sep 19, 8:38 PM CDT	Severe Thunderstorm Warning	FSD	Aurora, Beadle, Jerauld, Sanborn	52 min
Sep 19, 8:53 PM CDT	Severe Thunderstorm Warning	FSD	Aurora, Brule	52 min
Sep 19, 8:57 PM CDT	Severe Thunderstorm Warning	FSD	Gregory	48 min
Sep 19, 9:21 PM CDT	Severe Thunderstorm Warning	FSD	Beadle, Jerauld, Kingsbury, Miner, Sanborn	39 min
Sep 19, 9:41 PM CDT	Severe Thunderstorm Warning	FSD	Aurora, Davison, Hanson, Sanborn	49 min
Sep 19, 9:55 PM CDT	Severe Thunderstorm Warning	FSD	Beadle, Kingsbury, Miner, Sanborn	46 min
Sep 19, 10:00 PM CDT	Severe Thunderstorm Warning	FSD	Aurora, Davison, Douglas, Hanson, Hutchinson	45 min
Sep 19, 10:15 PM CDT	Severe Thunderstorm Warning	FSD	Kingsbury, Lake, Miner, Sanborn	45 min
Sep 19, 10:39 PM CDT	Severe Thunderstorm Warning	FSD	Hanson, Kingsbury, Lake, McCook, Miner, Minnehaha and 1 more	36 min
Sep 19, 11:04 PM CDT	Tornado Warning	FSD	Lake, McCook, Minnehaha, Moody	26 min
Sep 19, 11:08 PM CDT	Severe Thunderstorm Warning	FSD	Brookings, Lake, McCook, Minnehaha, Moody	52 min
Sep 19, 11:29 PM CDT	Severe Thunderstorm Warning	FSD	Lincoln, Minnehaha	46 min
Sep 19, 11:47 PM CDT	Severe Thunderstorm Warning	FSD	Brookings	43 min

Nearby

Tornado Warnings in South Dakota, 2017 Every tornado warning in 2017 Tornadoes 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.