Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 73, NWS Des Moines, IA

October 9, 2018Polk County, Warren County, Iowa

NWS Des Moines, IA issued this tornado warning at Oct 9, 2018, 6:30 PM CDT for Polk County, Warren County, Iowa. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Oct 9, 2018, 6:30 PM CDT (23:30 UTC)
Expired: Oct 9, 2018, 7:00 PM CDT
In force: 30 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.0 in

Counties Polk County, IA, Warren County, IA

The radar

The Des Moines radar (KDMX), 39 km from the middle of the area, began a volume at 23:31 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.

The watch it was issued in

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

Issued	Product	Office	Lasted
Oct 9, 1:46 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.5 hours before the alert went out and 233 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 592 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 28 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

021 
WFUS53 KDMX 092330
TORDMX
IAC153-181-100000-
/O.NEW.KDMX.TO.W.0073.181009T2330Z-181010T0000Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
630 PM CDT TUE OCT 9 2018

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  South central Polk County in central Iowa...
  North central Warren County in south central Iowa...

* Until 700 PM CDT.
    
* At 630 PM CDT, a severe thunderstorm capable of producing a tornado
  was located over Indianola, moving north at 35 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...
  Norwalk around 650 PM CDT.
  Carlisle, Southridge Mall and Des Moines Int'l Airport around 655 
  PM CDT.
  Des Moines and West Des Moines around 700 PM CDT.

Other locations impacted by this tornadic thunderstorm include Spring
Hill and Lake Ahquabi State Park.

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 4130 9352 4130 9361 4154 9373 4155 9352
TIME...MOT...LOC 2330Z 173DEG 30KT 4133 9357 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

Martin

3 follow-up statements

426 
WWUS53 KDMX 092341
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
641 PM CDT TUE OCT 9 2018

IAC153-181-100000-
/O.CON.KDMX.TO.W.0073.000000T0000Z-181010T0000Z/
Polk IA-Warren IA-
641 PM CDT TUE OCT 9 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 700 PM CDT FOR SOUTH
CENTRAL POLK AND NORTH CENTRAL WARREN COUNTIES...
    
At 640 PM CDT, a severe thunderstorm capable of producing a tornado
was 2 miles north of Indianola, moving north at 40 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...
  Norwalk, Carlisle and Southridge Mall around 650 PM CDT.
  Des Moines Int'l Airport around 655 PM CDT.
  Des Moines and West Des Moines around 700 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 4141 9353 4140 9361 4154 9373 4155 9352
TIME...MOT...LOC 2340Z 171DEG 33KT 4144 9358 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

Martin

117 
WWUS53 KDMX 092346
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
646 PM CDT TUE OCT 9 2018

IAC153-181-100000-
/O.CON.KDMX.TO.W.0073.000000T0000Z-181010T0000Z/
Polk IA-Warren IA-
646 PM CDT TUE OCT 9 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 700 PM CDT FOR SOUTH
CENTRAL POLK AND NORTH CENTRAL WARREN COUNTIES...
    
At 645 PM CDT, a severe thunderstorm capable of producing a tornado 
was located 4 miles south of Southridge Mall, or just east of 
Norwalk, moving north at 35 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...
  Southridge Mall around 650 PM CDT.
  Des Moines Int'l Airport around 655 PM CDT.
  Des Moines around 700 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 4145 9353 4144 9360 4154 9366 4155 9352
TIME...MOT...LOC 2345Z 173DEG 30KT 4149 9359 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

Martin

459 
WWUS53 KDMX 092355
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
655 PM CDT TUE OCT 9 2018

IAC153-181-100005-
/O.EXP.KDMX.TO.W.0073.000000T0000Z-181010T0000Z/
Polk IA-Warren IA-
655 PM CDT TUE OCT 9 2018

...THE TORNADO WARNING FOR SOUTH CENTRAL POLK AND NORTH CENTRAL
WARREN COUNTIES WILL EXPIRE AT 700 PM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

A Tornado Watch remains in effect until 900 PM CDT for central and
south central Iowa.

LAT...LON 4145 9353 4144 9360 4154 9366 4155 9352
TIME...MOT...LOC 2355Z 173DEG 30KT 4157 9360 

$$

Martin

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 8, 7:11 PM CDT	Severe Thunderstorm Warning	DMX	Decatur, Wayne	34 min
Oct 8, 7:23 PM CDT	Tornado Warning	DMX	Clarke, Decatur	37 min
Oct 8, 7:59 PM CDT	Tornado Warning Tornado observed	DMX	Clarke, Lucas, Warren	31 min
Oct 8, 9:54 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska, Poweshiek	21 min
Oct 8, 10:03 PM CDT	Tornado Warning	DMX	Poweshiek	15 min
Oct 8, 10:26 PM CDT	River Flood Warning	DMX	Polk	7 days
Oct 8, 10:26 PM CDT	River Flood Warning	DMX	Polk	7 days
Oct 8, 10:31 PM CDT	River Flood Watch	DMX	Decatur	3 hr
Oct 9, 12:58 AM CDT	River Flood Warning	DMX	Decatur	4 days
Oct 9, 1:48 AM CDT	Areal Flood Warning	DMX	Clarke, Decatur, Jasper, Lucas, Mahaska, Marion and 6 more	24 hr
Oct 9, 2:49 AM CDT	River Flood Warning	DMX	Polk, Story	3 days
Oct 9, 6:39 AM CDT	River Flood Warning	DMX	Marshall	7 days
Oct 9, 6:39 AM CDT	River Flood Warning	DMX	Black Hawk	6 days
Oct 9, 6:39 AM CDT	River Flood Warning	DMX	Dallas, Greene	5 days
Oct 9, 10:20 AM CDT	River Flood Warning	DMX	Black Hawk, Bremer, Butler	35 hr
Oct 9, 10:20 AM CDT	River Flood Warning	DMX	Lucas, Wayne	64 hr
Oct 9, 11:33 AM CDT	River Flood Warning	DMX	Dallas, Polk	6 days
Oct 9, 12:38 PM CDT	River Flood Watch	DMX	Davis, Wapello	10 hr
Oct 9, 2:16 PM CDT	Tornado Warning	DMX	Mahaska, Marion, Monroe	29 min
Oct 9, 3:22 PM CDT	River Flood Warning	DMX	Story	7 hr
Oct 9, 3:22 PM CDT	River Flood Warning	DMX	Story	20 hr
Oct 9, 3:32 PM CDT	Tornado Warning	DMX	Appanoose, Monroe	43 min
Oct 9, 3:42 PM CDT	Tornado Warning	DMX	Mahaska, Marion, Monroe	22 min
Oct 9, 4:21 PM CDT	Tornado Warning Tornado observed	DMX	Poweshiek, Tama	24 min
Oct 9, 4:28 PM CDT	Tornado Warning	DMX	Ringgold, Taylor	47 min
Oct 9, 4:47 PM CDT	River Flood Watch	DMX	Jasper, Marion, Polk	29 hr
Oct 9, 4:58 PM CDT	Tornado Warning Tornado observed	DMX	Tama	32 min
Oct 9, 4:59 PM CDT	Tornado Warning	DMX	Jasper, Poweshiek	31 min
Oct 9, 5:13 PM CDT	Tornado Warning	DMX	Adair, Adams, Union	32 min
Oct 9, 5:44 PM CDT	Tornado Warning Tornado observed	DMX	Adair	46 min
Oct 9, 6:11 PM CDT	Tornado Warning Tornado observed	DMX	Adair, Dallas, Guthrie	49 min

Nearby

Tornado Warnings in Iowa, 2018 Every tornado warning in 2018 Tornadoes in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.