Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 19, NWS Des Moines, IA

June 20, 2018Webster County, Iowa

NWS Des Moines, IA issued this tornado warning at Jun 20, 2018, 2:43 PM CDT for Webster County, Iowa. It was in force for 47 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: Jun 20, 2018, 2:43 PM CDT (19:43 UTC)
Expired: Jun 20, 2018, 3:30 PM CDT
In force: 47 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Webster County, IA

The radar

The Des Moines radar (KDMX), 74 km from the middle of the area, began a volume at 19:43 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

Omaha, NE (KOAX), launched 12:00Z, 7.7 hours before the alert went out and 214 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: 111 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 520 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 1 m²/s²
0-3 km storm-relative helicity: 127 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

659 
WFUS53 KDMX 201943
TORDMX
IAC187-202030-
/O.NEW.KDMX.TO.W.0019.180620T1943Z-180620T2030Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
243 PM CDT WED JUN 20 2018

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  South central Webster County in central Iowa...

* Until 330 PM CDT.
    
* At 243 PM CDT, a severe thunderstorm capable of producing a tornado
  was located 7 miles southeast of Gowrie, or 17 miles northeast of
  Jefferson, moving north at 15 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
  south central Webster County, including the following locations...
  Dolliver Memorial State Park and Harcourt.

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 4239 9408 4221 9412 4221 9424 4237 9428
TIME...MOT...LOC 1943Z 174DEG 12KT 4222 9417 

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

$$

Donavon

2 follow-up statements

404 
WWUS53 KDMX 202005
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
305 PM CDT WED JUN 20 2018

IAC187-202030-
/O.CON.KDMX.TO.W.0019.000000T0000Z-180620T2030Z/
Webster IA-
305 PM CDT WED JUN 20 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 330 PM CDT FOR SOUTH
CENTRAL WEBSTER COUNTY...
    
At 304 PM CDT, a severe thunderstorm capable of producing a tornado
was located 7 miles east of Gowrie, or 14 miles south of Fort Dodge,
moving north at 15 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...
Harcourt and Dolliver Memorial 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 4239 9408 4226 9411 4226 9419 4238 9423
TIME...MOT...LOC 2004Z 200DEG 12KT 4230 9415 

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

$$

Donavon

148 
WWUS53 KDMX 202025
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
325 PM CDT WED JUN 20 2018

IAC187-202034-
/O.EXP.KDMX.TO.W.0019.000000T0000Z-180620T2030Z/
Webster IA-
325 PM CDT WED JUN 20 2018

...THE TORNADO WARNING FOR SOUTH CENTRAL WEBSTER COUNTY WILL EXPIRE
AT 330 PM CDT...
        
The storm which prompted the warning has moved north of the area.
Therefore, the warning will be allowed to expire.

A Tornado Watch remains in effect until 700 PM CDT for central Iowa.

LAT...LON 4239 9408 4226 9411 4226 9419 4238 9423
TIME...MOT...LOC 2024Z 174DEG 12KT 4236 9416 

$$

Donavon

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 19, 8:39 PM CDT	River Flood Warning	DMX	Polk	9 days
Jun 19, 8:39 PM CDT	River Flood Warning	DMX	Polk	8 days
Jun 20, 1:19 AM CDT	Special Weather Statement	DMX	Carroll	56 min
Jun 20, 2:12 AM CDT	Flash Flood Warning	DMX	Calhoun, Webster	5 hr
Jun 20, 2:17 AM CDT	Special Weather Statement	DMX	Boone	58 min
Jun 20, 4:28 AM CDT	Flash Flood Watch	DMX	Adair, Audubon, Boone, Calhoun, Carroll, Cass and 18 more	23 hr
Jun 20, 10:38 AM CDT	River Flood Warning	DMX	Webster	19 days
Jun 20, 10:38 AM CDT	River Flood Warning	DMX	Boone, Hamilton, Webster	3 days
Jun 20, 10:43 AM CDT	River Flood Watch	DMX	Dallas, Polk	6 days
Jun 20, 10:43 AM CDT	River Flood Watch	DMX	Polk	6 days
Jun 20, 10:43 AM CDT	River Flood Watch	DMX	Black Hawk	34 hr
Jun 20, 10:43 AM CDT	River Flood Watch	DMX	Polk, Story	7 hr
Jun 20, 10:43 AM CDT	River Flood Watch	DMX	Jasper, Marion, Polk	10 hr
Jun 20, 10:43 AM CDT	River Flood Watch	DMX	Emmet	6 hr
Jun 20, 10:43 AM CDT	River Flood Watch	DMX	Humboldt	10 hr
Jun 20, 12:49 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Mahaska, Marion	41 min
Jun 20, 2:16 PM CDT	Tornado Warning	DMX	Carroll, Greene	29 min
Jun 20, 2:22 PM CDT	Tornado Warning	DMX	Boone, Dallas, Greene	25 min
Jun 20, 2:26 PM CDT	Special Weather Statement	DMX	Davis, Wapello	49 min
Jun 20, 2:43 PM CDT	Special Weather Statement	DMX	Polk, Story	62 min
Jun 20, 2:46 PM CDT	Tornado Warning	DMX	Calhoun, Greene	17 min
Jun 20, 3:02 PM CDT	Tornado Warning Tornado observed	DMX	Hardin	11 min
Jun 20, 3:16 PM CDT	Tornado Warning Tornado observed	DMX	Hardin	29 min
Jun 20, 3:18 PM CDT	Tornado Warning Tornado observed	DMX	Grundy, Hardin	57 min
Jun 20, 3:21 PM CDT	Tornado Warning	DMX	Humboldt, Kossuth	39 min
Jun 20, 3:24 PM CDT	Tornado Warning	DMX	Webster	37 min
Jun 20, 3:57 PM CDT	Tornado Warning	DMX	Grundy, Hardin	33 min
Jun 20, 4:06 PM CDT	Severe Thunderstorm Warning	DMX	Hancock, Humboldt, Kossuth, Wright	39 min
Jun 20, 4:13 PM CDT	Flash Flood Warning	DMX	Humboldt, Kossuth, Palo Alto, Pocahontas	6 hr
Jun 20, 4:25 PM CDT	Flash Flood Warning	DMX	Humboldt, Kossuth	6 hr
Jun 20, 5:06 PM CDT	River Flood Warning	DMX	Emmet	38 days
Jun 20, 5:20 PM CDT	River Flood Warning	DMX	Polk, Story	3 hr
Jun 20, 5:34 PM CDT	Tornado Warning Tornado observed	DMX	Mahaska, Monroe, Wapello	41 min
Jun 20, 6:05 PM CDT	Severe Thunderstorm Warning	DMX	Davis, Wapello	41 min
Jun 20, 6:45 PM CDT	Severe Thunderstorm Warning	DMX	Story	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.