Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 5, NWS Des Moines, IA

May 3, 20184 counties in Iowa

NWS Des Moines, IA issued this tornado warning at May 3, 2018, 5:43 PM CDT for 4 counties in Iowa. It was in force for 21 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
May 3, 2018, 5:43 PM CDT (22:43 UTC)
Expired
May 3, 2018, 6:04 PM CDT
In force
21 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Tornado
Radar indicated
Hail
1.0 in

Counties Boone County, IA, Dallas County, IA, Polk County, IA, Story County, IA

The radar

The Des Moines radar (KDMX), 9 km from the middle of the area, began a volume at 22:48 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.

IssuedProductOfficeLasted
May 3, 2:57 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.7 hours before the alert went out and 231 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-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2018-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2018-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 66 square meters per square second.1939587897117136Sfc1 km3 km6 km9 kmRMLM
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.

386 
WFUS53 KDMX 032243
TORDMX
IAC015-049-153-169-032315-
/O.NEW.KDMX.TO.W.0005.180503T2243Z-180503T2315Z/

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

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Northwestern Polk County in central Iowa...
  Southwestern Story County in central Iowa...
  Southeastern Boone County in central Iowa...
  Northeastern Dallas County in central Iowa...

* Until 615 PM CDT.

* At 543 PM CDT, a severe thunderstorm capable of producing a 
  tornado was located over Clive, moving northeast at 40 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...
  Ankeny and Granger around 555 PM CDT. 
  Polk City and Saylorville Lake around 600 PM CDT. 
  Big Creek Lake around 605 PM CDT. 
  Slater around 610 PM CDT. 
  Huxley around 615 PM CDT. 

Other locations impacted by this tornadic thunderstorm include Big
Creek State Park, Sheldahl, Alleman, Elkhart, Cambridge and Ankeny
Regional Airport.

This includes Interstate 35 between mile markers 92 and 105.
 
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 4170 9356 4176 9387 4195 9384 4189 9349
TIME...MOT...LOC 2243Z 208DEG 34KT 4161 9379 

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

$$

Donavon
1 follow-up statement
786 
WWUS53 KDMX 032304
SVSDMX

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

IAC015-049-153-169-032313-
/O.CAN.KDMX.TO.W.0005.000000T0000Z-180503T2315Z/
Polk IA-Story IA-Boone IA-Dallas IA-
604 PM CDT THU MAY 3 2018

...THE TORNADO WARNING FOR NORTHWESTERN POLK...SOUTHWESTERN STORY...
SOUTHEASTERN BOONE AND NORTHEASTERN DALLAS COUNTIES 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 severe thunderstorm watch remains in effect until 800 PM CDT for
central Iowa.

LAT...LON 4170 9356 4176 9387 4195 9384 4189 9349
TIME...MOT...LOC 2302Z 208DEG 34KT 4179 9367 

$$

Donavon

The office that day

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

IssuedProductOfficeCountiesLasted
May 2, 7:47 PM CDTFlash Flood WarningDMXAdams, Ringgold, Taylor, Union6 hr
May 2, 8:05 PM CDTSevere Thunderstorm WarningDMXRinggold, Taylor40 min
May 2, 8:43 PM CDTSevere Thunderstorm WarningDMXClarke, Decatur, Ringgold, Taylor, Union47 min
May 2, 9:43 PM CDTSpecial Weather StatementDMXWayne47 min
May 2, 11:14 PM CDTRiver Flood WarningDMXTaylor49 min
May 2, 11:33 PM CDTSevere Thunderstorm WarningDMXAppanoose, Davis, Monroe, Wapello29 min
May 3, 12:00 PM CDTSpecial Weather StatementDMXGreene30 min
May 3, 2:24 PM CDTRiver Flood WatchDMXBlack Hawk6 days
May 3, 5:12 PM CDTTornado WarningDMXAdair, Guthrie33 min
May 3, 5:26 PM CDTTornado WarningDMXDallas, Madison, Polk34 min
May 3, 5:39 PM CDTSevere Thunderstorm WarningDMXJasper, Polk, Warren25 min
May 3, 5:45 PM CDTTornado WarningDMXDallas, Guthrie30 min
May 3, 5:48 PM CDTTornado WarningDMXAdair, Madison17 min
May 3, 6:23 PM CDTSpecial Weather StatementDMXUnion37 min
May 3, 6:25 PM CDTSevere Thunderstorm WarningDMXHamilton, Webster, Wright50 min
May 3, 6:51 PM CDTSpecial Weather StatementDMXClarke, Warren39 min

Nearby

Tornado Warnings in Iowa, 2018Every tornado warning in 2018Tornadoes 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.