Alert archive / Iowa / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 293, NWS Des Moines, IA

August 23, 2011Hamilton County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Aug 23, 2011, 5:55 AM CDT for Hamilton County, Iowa. It was in force for 35 min. 2 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
Aug 23, 2011, 5:55 AM CDT (10:55 UTC)
Expired
Aug 23, 2011, 6:30 AM CDT
In force
35 min
Issued by
NWS Des Moines, IA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Hamilton County, IA

The radar

The Des Moines radar (KDMX), 74 km from the middle of the area, began a volume at 10:57 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

TimeReportWhereRemark
Aug 23, 5:57 AM CDTHAIL 13 Se Webster City, IA
Aug 23, 6:06 AM CDTHAIL 0.884 Ene Kamrar, IATIME ESTIMATED FROM RADAR.

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.

IssuedProductOfficeLasted
Aug 23, 3:00 AM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 10.9 hours before the alert went out and 258 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 00:00Z on 2011-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3125 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2011-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 92 square meters per square second.193958Sfc1 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
3125 J/kg
Mixed-layer CIN
-39 J/kg
Mixed-layer LCL
970 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
92 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
1.5
Supercell composite
8.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

966 
WUUS53 KDMX 231055
SVRDMX
IAC079-231130-
/O.NEW.KDMX.SV.W.0293.110823T1055Z-110823T1130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
555 AM CDT TUE AUG 23 2011

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL HAMILTON COUNTY IN CENTRAL IOWA...

* UNTIL 630 AM CDT

* AT 552 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  WEBSTER CITY...OR 20 MILES EAST OF FORT DODGE...AND MOVING EAST AT
  40 MPH.

* LOCATIONS IMPACTED INCLUDE...
  JEWELL...KAMRAR AND ELLSWORTH.

THIS INCLUDES INTERSTATE 35 BETWEEN MILE MARKERS 133 AND 143.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO AN INTERIOR ROOM AND STAY AWAY FROM WINDOWS. IF YOU ARE IN A
MOBILE HOME...GET OUT NOW...AND SEEK SHELTER IN A REINFORCED
BUILDING.

&&

LAT...LON 4245 9346 4230 9346 4226 9347 4239 9391
      4249 9387
TIME...MOT...LOC 1056Z 285DEG 34KT 4241 9376
WIND...HAIL 60MPH 1.00IN

$$

DONAVON
2 follow-up statements
029 
WWUS53 KDMX 231109
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
609 AM CDT TUE AUG 23 2011

IAC079-231130-
/O.CON.KDMX.SV.W.0293.000000T0000Z-110823T1130Z/
HAMILTON IA-
609 AM CDT TUE AUG 23 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR EAST CENTRAL
HAMILTON COUNTY UNTIL 630 AM CDT...

AT 606 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 5 MILES
NORTH OF JEWELL...OR 21 MILES SOUTHWEST OF IOWA FALLS...MOVING EAST
AT 40 MPH.

LOCATIONS IMPACTED INCLUDE...
  ELLSWORTH.

THIS INCLUDES INTERSTATE 35 BETWEEN MILE MARKERS 132 AND 143.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PREPARE FOR LARGE HAIL...DAMAGING WINDS AND DEADLY CLOUD TO GROUND
LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY
INSIDE A REINFORCED BUILDING AND AWAY FROM WINDOWS.

&&

LAT...LON 4226 9347 4234 9374 4247 9368 4247 9363
      4245 9346 4229 9346
TIME...MOT...LOC 1109Z 285DEG 34KT 4238 9360
WIND...HAIL 60MPH 1.00IN

$$

DONAVON
451 
WWUS53 KDMX 231126
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
626 AM CDT TUE AUG 23 2011

IAC079-231136-
/O.EXP.KDMX.SV.W.0293.000000T0000Z-110823T1130Z/
HAMILTON IA-
626 AM CDT TUE AUG 23 2011

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL HAMILTON COUNTY
WILL EXPIRE AT 630 AM CDT...

THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE WARNED
AREA.

ADDITIONAL STRONG THUNDERSTORMS ARE STILL POSSIBLE...AND A SEVERE 
THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 8 AM.

LAT...LON 4226 9347 4234 9374 4247 9368 4247 9363
      4245 9346 4229 9346
TIME...MOT...LOC 1126Z 285DEG 34KT 4234 9339

$$

DONAVON

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 23, 2:05 AM CDTSevere Thunderstorm WarningDMXEmmet, Palo Alto, Pocahontas55 min
Aug 23, 2:25 AM CDTSevere Thunderstorm WarningDMXHancock, Humboldt, Kossuth, Wright65 min
Aug 23, 2:49 AM CDTSevere Thunderstorm WarningDMXHumboldt, Webster, Wright41 min
Aug 23, 3:14 AM CDTSevere Thunderstorm WarningDMXFranklin, Hamilton, Hardin, Webster, Wright61 min
Aug 23, 6:18 AM CDTSevere Thunderstorm WarningDMXHardin21 min
Aug 23, 6:23 AM CDTSevere Thunderstorm WarningDMXCerro Gordo, Hancock, Kossuth, Winnebago, Worth37 min
Aug 23, 6:57 AM CDTSevere Thunderstorm WarningDMXCerro Gordo, Worth34 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2011Every severe thunderstorm warning in 2011

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.