Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 11, NWS Des Moines, IA

May 3, 2018Marion County, Iowa

NWS Des Moines, IA issued this tornado warning at May 3, 2018, 7:54 PM CDT for Marion County, Iowa. It was in force for 36 min. 1 report 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, 7:54 PM CDT (00:54 UTC)
Expired: May 3, 2018, 8:30 PM CDT
In force: 36 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.0 in

County Marion County, IA

The radar

The Des Moines radar (KDMX), 69 km from the middle of the area, began a volume at 00:58 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, 8:17 PM CDT	TORNADO	2 Ene Lake Red Rock, IA

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

Davenport, (KDVN), launched 00:00Z, 0.9 hours before the alert went out and 209 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: 1 J/kg
Mixed-layer CIN: -170 J/kg
Mixed-layer LCL: 824 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 64 m²/s²
0-3 km storm-relative helicity: 101 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

770 
WFUS53 KDMX 040054
TORDMX
IAC125-040130-
/O.NEW.KDMX.TO.W.0011.180504T0054Z-180504T0130Z/

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

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Northeastern Marion County in south central Iowa...

* Until 830 PM CDT.

* At 754 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Pleasantville, or 7 miles northwest of Knoxville,
  moving east at 30 mph.

  HAZARD...Tornado and quarter size hail. 

  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...
  Lake Red Rock around 800 PM CDT. 
  Pella around 820 PM CDT. 

Other locations impacted by this tornadic thunderstorm include Elk
Rock State Park and Pella Municipal Airport.

People attending Pella Tulip Festival should seek safe shelter 
immediately!

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 4137 9289 4137 9319 4145 9320 4151 9291
      4151 9290
TIME...MOT...LOC 0054Z 252DEG 26KT 4140 9319 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

Donavon

2 follow-up statements

896 
WWUS53 KDMX 040117
SVSDMX

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

IAC125-040130-
/O.CON.KDMX.TO.W.0011.000000T0000Z-180504T0130Z/
Marion IA-
817 PM CDT THU MAY 3 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 830 PM CDT FOR
NORTHEASTERN MARION COUNTY...
    
At 817 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Pella, moving east at 30 mph.

HAZARD...Tornado and quarter size hail. 

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. 

People attending Pella Tulip Festival should seek safe shelter 
immediately!

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 4137 9289 4140 9309 4147 9309 4151 9291
      4151 9290
TIME...MOT...LOC 0117Z 252DEG 26KT 4145 9298 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

Donavon

833 
WWUS53 KDMX 040126
SVSDMX

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

IAC125-040136-
/O.EXP.KDMX.TO.W.0011.000000T0000Z-180504T0130Z/
Marion IA-
826 PM CDT THU MAY 3 2018

...THE TORNADO WARNING FOR NORTHEASTERN MARION COUNTY WILL EXPIRE AT
830 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore the warning will be allowed to expire.

A severe thunderstorm watch remains in effect until 900 PM CDT for
central and south central Iowa.

LAT...LON 4137 9289 4140 9309 4147 9309 4151 9291
      4151 9290
TIME...MOT...LOC 0126Z 252DEG 26KT 4147 9291 

$$

Donavon

The office that day

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

Issued	Product	Office	Counties	Lasted
May 3, 7:25 PM CDT	Tornado Warning	DMX	Jasper, Marion, Polk, Warren	35 min
May 3, 7:36 PM CDT	Tornado Warning	DMX	Marion, Warren	24 min
May 3, 7:45 PM CDT	Tornado Warning Tornado observed	DMX	Jasper, Marion	30 min
May 3, 7:50 PM CDT	Severe Thunderstorm Warning	DMX	Jasper, Marshall, Story	55 min
May 3, 8:23 PM CDT	Severe Thunderstorm Warning	DMX	Grundy, Hardin, Marshall, Tama	52 min
May 3, 8:28 PM CDT	Tornado Warning	DMX	Marshall, Tama	22 min
May 3, 8:48 PM CDT	Severe Thunderstorm Warning	DMX	Poweshiek, Tama	42 min
May 3, 9:11 PM CDT	Special Weather Statement	DMX	Black Hawk	64 min
May 3, 9:26 PM CDT	River Flood Warning	DMX	Black Hawk	6 days
May 3, 9:30 PM CDT	River Flood Watch	DMX	Black Hawk	5 days
May 3, 9:30 PM CDT	River Flood Watch	DMX	Wright	37 hr
May 3, 9:30 PM CDT	River Flood Watch	DMX	Polk	13 hr
May 3, 9:30 PM CDT	River Flood Warning	DMX	Webster	6 days
May 4, 12:33 AM CDT	Special Weather Statement	DMX	Black Hawk, Bremer	27 min
May 4, 10:29 AM CDT	River Flood Warning	DMX	Black Hawk, Bremer, Butler	70 hr
May 4, 10:29 AM CDT	River Flood Warning	DMX	Black Hawk	72 hr
May 4, 10:29 AM CDT	River Flood Warning	DMX	Black Hawk, Bremer, Butler	66 hr

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.