Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 4, NWS Des Moines, IA

May 3, 2018Dallas County, Madison County, Polk County, Iowa

NWS Des Moines, IA issued this tornado warning at May 3, 2018, 5:26 PM CDT for Dallas County, Madison County, Polk County, Iowa. It was in force for 34 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: May 3, 2018, 5:26 PM CDT (22:26 UTC)
Expired: May 3, 2018, 6:00 PM CDT
In force: 34 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Dallas County, IA, Madison County, IA, Polk County, IA

The radar

The Des Moines radar (KDMX), 23 km from the middle of the area, began a volume at 22:28 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.

What was reported inside it

Time	Report	Where	Remark
May 3, 5:34 PM CDT	HAIL 0.75	3 Sw Clive, IA	ROTATION IN CLOUD, DIME TO PENNY HAIL.
May 3, 5:35 PM CDT	TSTM WND GST 60	2 Wnw Urbandale, IA	AT LEAST 60 MPH WINDS ALONG WITH COPIOUS AMOUNTS OF SMALL HAIL.
May 3, 5:42 PM CDT	FUNNEL CLOUD	2 W Grimes, IA	FUNNEL CLOUD REPORTED NEAR THE DALLAS CENTER GRIMES HIGH SCHOOL.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

Issued	Product	Office	Lasted
May 3, 2:57 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.4 hours before the alert went out and 213 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: 511 m above ground
0-6 km bulk shear: 66 kt
0-1 km storm-relative helicity: 66 m²/s²
0-3 km storm-relative helicity: 83 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

Open this sounding in Storm Lab

The text

As transmitted.

416 
WFUS53 KDMX 032226
TORDMX
IAC049-121-153-032300-
/O.NEW.KDMX.TO.W.0004.180503T2226Z-180503T2300Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
526 PM CDT THU MAY 3 2018

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Southwestern Polk County in central Iowa...
  Northeastern Madison County in south central Iowa...
  Southeastern Dallas County in central Iowa...

* Until 600 PM CDT.

* At 526 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Van Meter, or 7 miles southwest of West Des
  Moines, 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. 

* This dangerous storm will be near...
  Jordan Creek Town Center around 540 PM CDT. 
  West Des Moines, Waukee and Valley West Mall around 545 PM CDT. 
  Urbandale, Clive, Windsor Heights, Merle Hay Mall and Drake 
  Stadium And Knapp Center around 550 PM CDT. 
  Des Moines, Johnston and Grimes around 555 PM CDT. 
  Ankeny, Saylorville and Saylorville Lake around 600 PM CDT. 

Other locations impacted by this tornadic thunderstorm include Ankeny
Regional Airport, Walnut Woods State Park, Margo Frankel Woods State
Park and Badger Creek State Park.

This includes the following highways...
 Interstate 35 between mile markers 67 and 72, and between mile
markers 90 and 91.
 Interstate 80 between mile markers 112 and 136.
 Interstate 235 between mile markers 1 and 5.

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 4146 9399 4178 9393 4171 9353 4151 9375
      4151 9379 4147 9379 4141 9386
TIME...MOT...LOC 2226Z 210DEG 30KT 4147 9388 

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

$$

Donavon

2 follow-up statements

479 
WWUS53 KDMX 032234
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
534 PM CDT THU MAY 3 2018

IAC049-121-153-032300-
/O.CON.KDMX.TO.W.0004.000000T0000Z-180503T2300Z/
Polk IA-Madison IA-Dallas IA-
534 PM CDT THU MAY 3 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 600 PM CDT FOR
SOUTHWESTERN POLK...NORTHEASTERN MADISON AND SOUTHEASTERN DALLAS
COUNTIES...
    
At 534 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Jordan Creek Town Center, or near West Des Moines,
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...  

This includes the following highways...
 Interstate 35 between mile markers 67 and 72, and between mile 
markers 90 and 91.
 Interstate 80 between mile markers 112 and 136.
 Interstate 235 between mile markers 1 and 5.

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 4151 9398 4178 9393 4171 9353 4151 9375
      4151 9379 4147 9379
TIME...MOT...LOC 2234Z 209DEG 30KT 4153 9383 

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

$$

Donavon

638 
WWUS53 KDMX 032255
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
555 PM CDT THU MAY 3 2018

IAC049-121-153-032305-
/O.EXP.KDMX.TO.W.0004.000000T0000Z-180503T2300Z/
Polk IA-Madison IA-Dallas IA-
555 PM CDT THU MAY 3 2018

...THE TORNADO WARNING FOR SOUTHWESTERN POLK...NORTHEASTERN MADISON
AND SOUTHEASTERN DALLAS COUNTIES WILL EXPIRE AT 600 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore the warning will be allowed to expire.

A severe thunderstorm watch remains in effect until 800 PM CDT for
central and south central Iowa.

LAT...LON 4151 9398 4178 9393 4171 9353 4151 9375
      4151 9379 4147 9379
TIME...MOT...LOC 2255Z 210DEG 30KT 4168 9372 

$$

Donavon

The office that day

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

Issued	Product	Office	Counties	Lasted
May 2, 7:47 PM CDT	Flash Flood Warning	DMX	Adams, Ringgold, Taylor, Union	6 hr
May 2, 8:05 PM CDT	Severe Thunderstorm Warning	DMX	Ringgold, Taylor	40 min
May 2, 8:43 PM CDT	Severe Thunderstorm Warning	DMX	Clarke, Decatur, Ringgold, Taylor, Union	47 min
May 2, 9:43 PM CDT	Special Weather Statement	DMX	Wayne	47 min
May 2, 11:14 PM CDT	River Flood Warning	DMX	Taylor	49 min
May 2, 11:33 PM CDT	Severe Thunderstorm Warning	DMX	Appanoose, Davis, Monroe, Wapello	29 min
May 3, 12:00 PM CDT	Special Weather Statement	DMX	Greene	30 min
May 3, 2:24 PM CDT	River Flood Watch	DMX	Black Hawk	6 days
May 3, 5:12 PM CDT	Tornado Warning	DMX	Adair, Guthrie	33 min
May 3, 5:39 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Polk, Warren	25 min
May 3, 5:43 PM CDT	Tornado Warning	DMX	Boone, Dallas, Polk, Story	21 min
May 3, 5:45 PM CDT	Tornado Warning	DMX	Dallas, Guthrie	30 min
May 3, 5:48 PM CDT	Tornado Warning	DMX	Adair, Madison	17 min
May 3, 6:23 PM CDT	Special Weather Statement	DMX	Union	37 min
May 3, 6:25 PM CDT	Severe Thunderstorm Warning	DMX	Hamilton, Webster, Wright	50 min
May 3, 6:51 PM CDT	Special Weather Statement	DMX	Clarke, Warren	39 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.