Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 62, NWS Des Moines, IA

October 8, 2018Poweshiek County, Iowa

NWS Des Moines, IA issued this tornado warning at Oct 8, 2018, 10:03 PM CDT for Poweshiek County, Iowa. It was in force for 15 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 8, 2018, 10:03 PM CDT (03:03 UTC)
Expired: Oct 8, 2018, 10:18 PM CDT
In force: 15 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Poweshiek County, IA

The radar

The Des Moines radar (KDMX), 92 km from the middle of the area, began a volume at 03:07 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 nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 3.1 hours before the alert went out and 177 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: 316 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 1260 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 113 m²/s²
0-3 km storm-relative helicity: 133 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.2

Open this sounding in Storm Lab

The text

As transmitted.

327 
WFUS53 KDMX 090303
TORDMX
IAC157-090330-
/O.NEW.KDMX.TO.W.0062.181009T0303Z-181009T0330Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
1003 PM CDT MON OCT 8 2018

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Northwestern Poweshiek County in central Iowa...

* Until 1030 PM CDT.
    
* At 1003 PM CDT, a severe thunderstorm capable of producing a
  tornado was located near Grinnell, moving northeast at 45 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 Poweshiek County, including the following locations...
  Grinnell Regional Airport.

This includes Interstate 80 between mile markers 182 and 189.
 
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 4167 9261 4168 9275 4186 9267 4186 9246
TIME...MOT...LOC 0303Z 214DEG 41KT 4172 9264 

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

$$

REV

2 follow-up statements

933 
WWUS53 KDMX 090313
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
1013 PM CDT MON OCT 8 2018

IAC157-090330-
/O.CON.KDMX.TO.W.0062.000000T0000Z-181009T0330Z/
Poweshiek IA-
1013 PM CDT MON OCT 8 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1030 PM CDT FOR
NORTHWESTERN POWESHIEK COUNTY...
    
At 1013 PM CDT, a severe thunderstorm capable of producing a tornado
was located 7 miles east of Grinnell, moving northeast 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.

Locations impacted include...
Grinnell and Grinnell Regional Airport. 

This includes Interstate 80 between mile markers 182 and 189.
 
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 4167 9261 4168 9275 4186 9267 4186 9246
TIME...MOT...LOC 0313Z 207DEG 30KT 4177 9260 

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

$$

REV

682 
WWUS53 KDMX 090318
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
1018 PM CDT MON OCT 8 2018

IAC157-090328-
/O.CAN.KDMX.TO.W.0062.000000T0000Z-181009T0330Z/
Poweshiek IA-
1018 PM CDT MON OCT 8 2018

...THE TORNADO WARNING FOR NORTHWESTERN POWESHIEK COUNTY 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.  However gusty winds and
heavy rain are still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Des Moines .

LAT...LON 4167 9261 4168 9275 4186 9267 4186 9246
TIME...MOT...LOC 0318Z 214DEG 41KT 4182 9255 

$$

REV

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, 10:26 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
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.