Alert archive / Iowa / Tornado Warnings in 2017

Tornado Warning 10, NWS Des Moines, IA

April 19, 2017Calhoun County, Carroll County, Greene County, Iowa

NWS Des Moines, IA issued this tornado warning at Apr 19, 2017, 7:56 PM CDT for Calhoun County, Carroll County, Greene County, Iowa. It was in force for 34 min. 3 reports 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: Apr 19, 2017, 7:56 PM CDT (00:56 UTC)
Expired: Apr 19, 2017, 8:30 PM CDT
In force: 34 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.75 in

Counties Calhoun County, IA, Carroll County, IA, Greene County, IA

The radar

The Des Moines radar (KDMX), 93 km from the middle of the area, began a volume at 01:00 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
Apr 19, 8:00 PM CDT	TORNADO	2 Sw Carroll, IA	CHASER REPORTED A TORNADO TOUCHED DOWN JUST SW OF CARROLL. TREES DOWN AND DAMAGE TO A FEW OUT BUILDINGS. TIME RADAR ESTIMATED.
Apr 19, 8:04 PM CDT	TORNADO	2 Se Carroll, IA	CARROLL COUNTY DISPATCH RELAYED REPORTS OF MACHINE SHED WITH ROOF AND DOORS BLOWN OFF.
Apr 19, 8:33 PM CDT	TSTM WND GST 60	1 Nnw Scranton, IA	PEA SIZE HAIL AND WATER PONDING IN THE STREETS AS WELL.

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
Apr 19, 3:23 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 0.9 hours before the alert went out and 156 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: 38 J/kg
Mixed-layer CIN: -269 J/kg
Mixed-layer LCL: 820 m above ground
0-6 km bulk shear: 70 kt
0-1 km storm-relative helicity: 222 m²/s²
0-3 km storm-relative helicity: 238 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.5

Open this sounding in Storm Lab

The text

As transmitted.

024 
WFUS53 KDMX 200056
TORDMX
IAC025-027-073-200130-
/O.NEW.KDMX.TO.W.0010.170420T0056Z-170420T0130Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
756 PM CDT WED APR 19 2017

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Northwestern Greene County in west central Iowa...
  Southeastern Calhoun County in west central Iowa...
  Central Carroll County in west central Iowa...

* Until 830 PM CDT.

* At 755 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Carroll, moving northeast at 50 mph.

  HAZARD...Tornado and golf 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 dangerous storm will be near...
  Carroll around 805 PM CDT. 
  Glidden around 810 PM CDT. 

Other locations impacted by this tornadic thunderstorm include Hobbs
County Park, Ralston, Churdan, Lohrville, Lidderdale, Templeton,
Arthur N Neu Airport, Willey, Swan Lake State Park and Halbur.

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 4189 9497 4205 9508 4233 9449 4210 9431
TIME...MOT...LOC 0055Z 241DEG 43KT 4201 9494 

TORNADO...RADAR INDICATED
HAIL...1.75IN

$$

REV

2 follow-up statements

086 
WWUS53 KDMX 200106
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
806 PM CDT WED APR 19 2017

IAC025-027-073-200130-
/O.CON.KDMX.TO.W.0010.000000T0000Z-170420T0130Z/
Greene IA-Calhoun IA-Carroll IA-
806 PM CDT WED APR 19 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 830 PM CDT FOR
NORTHWESTERN GREENE...SOUTHEASTERN CALHOUN AND NORTHEASTERN CARROLL
COUNTIES...
        
At 805 PM CDT, a confirmed tornado was located just south of 
Carroll, moving east at 45 mph.

HAZARD...Damaging tornado and quarter size hail. 

SOURCE...Radar confirmed tornado. 

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 tornado will be near...
  Glidden around 815 PM CDT. 

Other locations impacted by this tornadic thunderstorm include Hobbs
County Park, Ralston, Churdan, Lohrville, Lidderdale, Arthur N Neu
Airport, Swan Lake State Park and Lanesboro.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. 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 4198 9488 4205 9493 4233 9449 4210 9431
TIME...MOT...LOC 0105Z 247DEG 39KT 4205 9482 

TORNADO...OBSERVED
HAIL...1.00IN

$$

Small

491 
WWUS53 KDMX 200135
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
835 PM CDT WED APR 19 2017

IAC025-027-073-200143-
/O.EXP.KDMX.TO.W.0010.000000T0000Z-170420T0130Z/
Greene IA-Calhoun IA-Carroll IA-
835 PM CDT WED APR 19 2017

...THE TORNADO WARNING FOR NORTHWESTERN GREENE...SOUTHEASTERN CALHOUN
AND NORTHEASTERN CARROLL COUNTIES HAS EXPIRED...
    
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 parts of the 
area. However small hail is still possible with this thunderstorm.

A tornado watch remains in effect until 1000 PM CDT for west central
Iowa.

Remember, a Severe Thunderstorm Warning still remains in effect for 
portions of Calhoun and Greene Counties.

LAT...LON 4198 9488 4205 9493 4233 9449 4210 9431
TIME...MOT...LOC 0133Z 241DEG 43KT 4221 9442 

$$

Small

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 19, 7:02 PM CDT	Special Weather Statement	DMX	Calhoun, Carroll, Crawford, Sac	43 min
Apr 19, 7:18 PM CDT	Severe Thunderstorm Warning	DMX	Crawford	31 min
Apr 19, 7:37 PM CDT	Severe Thunderstorm Warning	DMX	Humboldt, Pocahontas, Webster	20 min
Apr 19, 7:37 PM CDT	Severe Thunderstorm Warning	DMX	Carroll	53 min
Apr 19, 8:14 PM CDT	Severe Thunderstorm Warning	DMX	Audubon, Carroll, Greene, Guthrie	46 min
Apr 19, 8:22 PM CDT	Severe Thunderstorm Warning	DMX	Calhoun, Webster	38 min
Apr 19, 8:29 PM CDT	Severe Thunderstorm Warning	DMX	Boone, Greene, Webster	46 min
Apr 19, 8:45 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Cass	25 min
Apr 19, 9:58 PM CDT	Severe Thunderstorm Warning	DMX	Adair, Madison	47 min
Apr 19, 10:18 PM CDT	Severe Thunderstorm Warning	DMX	Marshall, Story	42 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.