Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 25, NWS Des Moines, IA

June 20, 2018Webster County, Iowa

NWS Des Moines, IA issued this tornado warning at Jun 20, 2018, 3:24 PM CDT for Webster County, Iowa. It was in force for 37 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, 3:24 PM CDT (20:24 UTC)
Expired: Jun 20, 2018, 4:01 PM CDT
In force: 37 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), 84 km from the middle of the area, began a volume at 20:24 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
Jun 20, 3:04 PM CDT	Tornado Watch	SPC	4 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 8.4 hours before the alert went out and 225 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.

313 
WFUS53 KDMX 202024
TORDMX
IAC187-202115-
/O.NEW.KDMX.TO.W.0025.180620T2024Z-180620T2115Z/

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

The National Weather Service in Des Moines  has issued a

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

* Until 415 PM CDT.
    
* At 323 PM CDT, a severe thunderstorm capable of producing a tornado
  was located 9 miles south of Fort Dodge, moving north at 10 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...
  Fort Dodge and Fort Dodge Regional Airport around 415 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Coalville, Dolliver Memorial State Park, Otho, Woodman Hollow State
Park, Lehigh and Duncombe.

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 4235 9405 4235 9417 4254 9422 4257 9399
TIME...MOT...LOC 2023Z 173DEG 10KT 4238 9411 

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

$$

Donavon

2 follow-up statements

226 
WWUS53 KDMX 202049
SVSDMX

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

IAC187-202115-
/O.CON.KDMX.TO.W.0025.000000T0000Z-180620T2115Z/
Webster IA-
349 PM CDT WED JUN 20 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 415 PM CDT FOR
NORTHEASTERN WEBSTER COUNTY...
    
At 347 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Fort Dodge, moving north at 10 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation. At this time rotation on radar is 
         beginning to weaken.  If trends continue, the warning will 
         be cancelled early.

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...
  Fort Dodge and Fort Dodge Regional Airport around 415 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Coalville, Dolliver Memorial State Park, Otho, Woodman Hollow State
Park, Lehigh and Duncombe.

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 4235 9405 4235 9417 4254 9422 4257 9399
TIME...MOT...LOC 2047Z 173DEG 10KT 4245 9412 

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

$$

Donavon

409 
WWUS53 KDMX 202101
SVSDMX

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

IAC187-202111-
/O.CAN.KDMX.TO.W.0025.000000T0000Z-180620T2115Z/
Webster IA-
401 PM CDT WED JUN 20 2018

...THE TORNADO WARNING FOR WEBSTER 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.

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

LAT...LON 4235 9405 4235 9417 4254 9422 4257 9399
TIME...MOT...LOC 2059Z 173DEG 10KT 4249 9413 

$$

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, 2:43 PM CDT	Tornado Warning	DMX	Webster	47 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, 3:57 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.