Alert archive / Iowa / Tornado Warnings in 2017

Tornado Warning 5, NWS Sioux Falls, SD

May 17, 2017Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at May 17, 2017, 1:33 PM CDT for Sioux County, Iowa. It was in force for 27 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: May 17, 2017, 1:33 PM CDT (18:33 UTC)
Expired: May 17, 2017, 2:00 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), 87 km from the middle of the area, began a volume at 18:36 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
May 17, 2:10 PM CDT	TORNADO	3 Ne Alton, IA	TORNADO BRIEFLY TOUCHED THE GROUND.

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
May 17, 12:08 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 6.6 hours before the alert went out and 192 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: 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.

927 
WFUS53 KFSD 171833
TORFSD
IAC167-171900-
/O.NEW.KFSD.TO.W.0005.170517T1833Z-170517T1900Z/

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

The National Weather Service in Sioux Falls has issued a

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

* Until 200 PM CDT
    
* At 133 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Granville, or 8 miles southeast of 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...
  Alton around 150 PM CDT. 
  Hospers around 155 PM CDT. 
  Orange City around 200 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.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 4308 9615 4316 9592 4302 9586 4291 9586
      4291 9599
TIME...MOT...LOC 1833Z 148DEG 20KT 4293 9592 

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

$$

Ferguson

1 follow-up statement

628 
WWUS53 KFSD 171844
SVSFSD

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

IAC167-171900-
/O.CON.KFSD.TO.W.0005.000000T0000Z-170517T1900Z/
Sioux IA-
144 PM CDT WED MAY 17 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 200 PM CDT FOR
SOUTHEASTERN SIOUX COUNTY...
    
At 144 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Alton, or near Orange City, moving north at 40 mph.

HAZARD...Tornado and quarter 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
southeastern Sioux 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.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 4308 9615 4316 9592 4302 9586 4296 9592
      4294 9600
TIME...MOT...LOC 1844Z 159DEG 33KT 4301 9594 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

Ferguson

The office that day

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

Issued	Product	Office	Counties	Lasted
May 16, 7:43 PM CDT	Severe Thunderstorm Warning	FSD	Ida	33 min
May 16, 8:22 PM CDT	Severe Thunderstorm Warning	FSD	Buena Vista	23 min
May 17, 11:16 AM CDT	River Flood Warning	FSD	Clay	24 hr
May 17, 11:16 AM CDT	River Flood Warning	FSD	Buena Vista, Clay	24 hr
May 17, 11:16 AM CDT	River Flood Warning	FSD	Plymouth, Sioux	5 days
May 17, 11:16 AM CDT	River Flood Warning	FSD	Plymouth	6 days
May 17, 11:16 AM CDT	River Flood Warning	FSD	Clay	4 days
May 17, 11:16 AM CDT	River Flood Warning	FSD	Clay, Dickinson	59 hr
May 17, 1:56 PM CDT	Tornado Warning	FSD	Sioux	34 min
May 17, 2:03 PM CDT	Tornado Warning	FSD	Sioux	27 min
May 17, 2:28 PM CDT	Tornado Warning	FSD	Lyon, Sioux	32 min
May 17, 2:34 PM CDT	Severe Thunderstorm Warning	FSD	Lyon	26 min
May 17, 3:01 PM CDT	Tornado Warning	FSD	Lyon	29 min

Nearby

Tornado Warnings in Iowa, 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.