Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 65, NWS Des Moines, IA

October 9, 2018Mahaska County, Marion County, Monroe County, Iowa

NWS Des Moines, IA issued this tornado warning at Oct 9, 2018, 3:42 PM CDT for Mahaska County, Marion County, Monroe County, Iowa. It was in force for 22 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, 3:42 PM CDT (20:42 UTC)
Expired: Oct 9, 2018, 4:04 PM CDT
In force: 22 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.0 in

Counties Mahaska County, IA, Marion County, IA, Monroe County, IA

The radar

The Des Moines radar (KDMX), 82 km from the middle of the area, began a volume at 20:42 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

Davenport, (KDVN), launched 12:00Z, 8.7 hours before the alert went out and 212 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: 459 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 1071 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 82 m²/s²
0-3 km storm-relative helicity: 116 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

As transmitted.

447 
WFUS53 KDMX 092042
TORDMX
IAC123-125-135-092115-
/O.NEW.KDMX.TO.W.0065.181009T2042Z-181009T2115Z/

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

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Northwestern Monroe County in south central Iowa...
  Southeastern Marion County in south central Iowa...
  West central Mahaska County in south central Iowa...

* Until 415 PM CDT.
    
* At 342 PM CDT, a severe thunderstorm capable of producing a 
  tornado was located 10 miles south of Knoxville, moving northeast 
  at 30 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 tornadic thunderstorm will remain over mainly rural areas of
  northwestern Monroe...southeastern Marion and west central Mahaska
  Counties, including the following locations... Harvey.

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 4114 9302 4115 9310 4139 9302 4136 9278
TIME...MOT...LOC 2042Z 202DEG 27KT 4117 9305 

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

$$

Martin

3 follow-up statements

137 
WWUS53 KDMX 092048
SVSDMX

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

IAC135-092058-
/O.CAN.KDMX.TO.W.0065.000000T0000Z-181009T2115Z/
Monroe IA-
348 PM CDT TUE OCT 9 2018

...THE TORNADO WARNING FOR NORTHWESTERN MONROE 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 900 PM CDT for south central
Iowa.

LAT...LON 4116 9300 4116 9309 4139 9302 4136 9278
TIME...MOT...LOC 2048Z 202DEG 27KT 4121 9303 

$$

IAC123-125-092115-
/O.CON.KDMX.TO.W.0065.000000T0000Z-181009T2115Z/
Marion IA-Mahaska IA-
348 PM CDT TUE OCT 9 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 415 PM CDT FOR
SOUTHEASTERN MARION AND WEST CENTRAL MAHASKA COUNTIES...
    
At 348 PM CDT, a severe thunderstorm capable of producing a tornado
was located 8 miles southeast of Knoxville, moving north at 30 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.

Locations impacted include...
Lake Red Rock and Harvey. 

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 4116 9300 4116 9309 4139 9302 4136 9278
TIME...MOT...LOC 2048Z 202DEG 27KT 4121 9303 

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

$$

Martin

665 
WWUS53 KDMX 092055
SVSDMX

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

IAC123-125-092115-
/O.CON.KDMX.TO.W.0065.000000T0000Z-181009T2115Z/
Marion IA-Mahaska IA-
355 PM CDT TUE OCT 9 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 415 PM CDT FOR
SOUTHEASTERN MARION AND WEST CENTRAL MAHASKA COUNTIES...
    
At 354 PM CDT, a severe thunderstorm capable of producing a tornado 
was located 5 miles southeast of Knoxville, moving northeast at 30 
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.

Locations impacted include...
Lake Red Rock and Harvey. 

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 4120 9301 4122 9307 4139 9302 4136 9278
TIME...MOT...LOC 2054Z 202DEG 27KT 4126 9301 

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

$$

Martin

159 
WWUS53 KDMX 092104
SVSDMX

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

IAC123-125-092113-
/O.CAN.KDMX.TO.W.0065.000000T0000Z-181009T2115Z/
Marion IA-Mahaska IA-
404 PM CDT TUE OCT 9 2018

...THE TORNADO WARNING FOR SOUTHEASTERN MARION AND WEST CENTRAL
MAHASKA COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning has been cancelled.

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

LAT...LON 4120 9301 4122 9307 4139 9302 4136 9278
TIME...MOT...LOC 2102Z 202DEG 27KT 4133 9297 

$$

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, 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
Oct 9, 6:30 PM CDT	Tornado Warning	DMX	Polk, Warren	30 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.