Alert archive / South Dakota / Tornado Warnings in 2017

Tornado Warning 23, NWS Sioux Falls, SD

July 11, 2017Brookings County, South Dakota

NWS Sioux Falls, SD issued this tornado warning at Jul 11, 2017, 9:19 PM CDT for Brookings County, 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: Jul 11, 2017, 9:19 PM CDT (02:19 UTC)
Expired: Jul 11, 2017, 9:45 PM CDT
In force: 26 min
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.5 in

County Brookings County, SD

The radar

The Sioux Falls radar (KFSD), 89 km from the middle of the area, began a volume at 02:18 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
Jul 11, 9:30 PM CDT	HAIL 1.5	5 W White, 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
Jul 11, 6:52 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 2.3 hours before the alert went out and 141 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: 586 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 3131 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 66 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

As transmitted.

586 
WFUS53 KFSD 120219
TORFSD
SDC011-120245-
/O.NEW.KFSD.TO.W.0023.170712T0219Z-170712T0245Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
919 PM CDT TUE JUL 11 2017

The National Weather Service in Sioux Falls has issued a

* Tornado Warning for...
  Central Brookings County in east central South Dakota...

* Until 945 PM CDT
    
* At 919 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Bruce, or 7 miles north of Brookings, moving
  southeast at 10 mph.

  HAZARD...Tornado and ping pong ball 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 tornadic thunderstorm will remain over mainly rural areas of
  central Brookings County.

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 4439 9686 4445 9683 4440 9662 4430 9667
TIME...MOT...LOC 0219Z 301DEG 7KT 4441 9682 

TORNADO...RADAR INDICATED
HAIL...1.50IN

$$

Ferguson

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 11, 7:33 PM CDT	Severe Thunderstorm Warning	FSD	Charles Mix, Gregory	42 min
Jul 11, 8:08 PM CDT	Severe Thunderstorm Warning	FSD	Aurora, Davison	37 min
Jul 11, 8:35 PM CDT	Severe Thunderstorm Warning	FSD	Aurora, Davison	40 min
Jul 11, 8:36 PM CDT	Severe Thunderstorm Warning	FSD	Hanson, McCook, Miner, Sanborn	24 min
Jul 11, 8:56 PM CDT	Severe Thunderstorm Warning	FSD	Brookings	34 min
Jul 11, 9:08 PM CDT	Severe Thunderstorm Warning	FSD	Davison, Hanson, Hutchinson	37 min
Jul 11, 9:25 PM CDT	Severe Thunderstorm Warning	FSD	Hanson, Hutchinson, McCook	35 min
Jul 11, 9:28 PM CDT	Tornado Warning	FSD	Brookings	32 min
Jul 11, 9:29 PM CDT	Severe Thunderstorm Warning	FSD	Brookings	31 min
Jul 11, 9:46 PM CDT	Severe Thunderstorm Warning	FSD	Brookings, Kingsbury	29 min
Jul 11, 9:57 PM CDT	Severe Thunderstorm Warning	FSD	Brookings, Kingsbury	33 min
Jul 11, 10:00 PM CDT	Severe Thunderstorm Warning	FSD	Brookings	30 min
Jul 11, 10:27 PM CDT	Severe Thunderstorm Warning	FSD	Brookings	33 min
Jul 11, 10:29 PM CDT	Severe Thunderstorm Warning	FSD	Brookings	31 min
Jul 11, 10:48 PM CDT	Severe Thunderstorm Warning	FSD	Brookings	27 min
Jul 11, 11:10 PM CDT	Severe Thunderstorm Warning	FSD	Brookings, Moody	35 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.