Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 114, NWS Quad Cities, IA

December 15, 2021Benton County, Iowa County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Dec 15, 2021, 8:23 PM CST for Benton County, Iowa County, Iowa. It was in force for 37 min. 4 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
Dec 15, 2021, 8:23 PM CST (02:23 UTC)
Expired
Dec 15, 2021, 9:00 PM CST
In force
37 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Tornado
Possible
Damage threat
Considerable
Hail
0.75 in
Wind
70.0 mph

Counties Benton County, IA, Iowa County, IA

The radar

The Quad Cities radar (KDVN), 124 km from the middle of the area, began a volume at 02:26 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
Dec 15, 8:24 PM CSTTSTM WND GST 65Norway, IAREPORT RELAYED BY EM.
Dec 15, 8:26 PM CSTTSTM WND GST 70Norway, IAREPORT RELAYED BY EM.
Dec 15, 8:30 PM CSTTSTM WND DMG1 Wsw Walford, IA*** 1 FATAL *** SEVERE THUNDERSTORMS WINDS CAUSED A SEMI-TRAILER BLOW-OVER. THE DRIVER WAS THROWN FROM THE VEHICLE AND PRONOUNCED DEAD AT THE SCENE.
Dec 15, 8:32 PM CSTTSTM WND GST 65Atkins, 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.

IssuedProductOfficeLasted
Dec 15, 5:30 PM CSTTornado WatchSPC6 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.4 hours before the alert went out and 130 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, Davenport, at 00:00Z on 2021-12-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 229 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, Davenport, at 00:00Z on 2021-12-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 433 square meters per square second.1939587897117Sfc1 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
229 J/kg
Mixed-layer CIN
-358 J/kg
Mixed-layer LCL
1061 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
433 m²/s²
0-3 km storm-relative helicity
496 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

878 
WUUS53 KDVN 160223
SVRDVN
IAC011-095-160300-
/O.NEW.KDVN.SV.W.0114.211216T0223Z-211216T0300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
823 PM CST Wed Dec 15 2021

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Eastern Benton County in east central Iowa...
  Eastern Iowa County in east central Iowa...

* Until 900 PM CST.

* At 823 PM CST, severe thunderstorms were located along a line
  extending from near Vinton to near Williamsburg, moving northeast
  at 55 mph.

  HAZARD...70 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Vinton, Marengo, Williamsburg, Atkins, Walford, Urbana, North
  English, Shellsburg, Newhall, Blairstown, Van Horne, Norway,
  Parnell, Amana, Conroy, Middle Amana, Vinton Memorial Airport,
  Upper South Amana, East Amana and High Amana.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1100 PM CST for southeastern,
northeastern and east central Iowa.

For your protection move to an interior room on the lowest floor of a
sturdy building.

A Tornado Watch remains in effect until 1100 PM CST for southeastern,
northeastern and east central Iowa.

&&

LAT...LON 4230 9208 4230 9184 4151 9183 4151 9211
TIME...MOT...LOC 0223Z 244DEG 50KT 4209 9201 4163 9199 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

McClure
2 follow-up statements
951 
WWUS53 KDVN 160234
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
834 PM CST Wed Dec 15 2021

IAC011-095-160300-
/O.CON.KDVN.SV.W.0114.000000T0000Z-211216T0300Z/
Benton IA-Iowa IA-
834 PM CST Wed Dec 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM CST
FOR EASTERN BENTON AND EASTERN IOWA COUNTIES...

At 834 PM CST, severe thunderstorms were located along a line
extending from near Shellsburg to near Oxford, moving northeast at 60
mph. 

HAZARD...70 mph wind gusts and penny size hail.

SOURCE...Trained weather spotters. A 65 mph wind gust was measured in
         Atkins at 832 PM. 

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
Vinton, Marengo, Williamsburg, Atkins, Walford, Urbana, North
English, Shellsburg, Newhall, Blairstown, Van Horne, Norway, Parnell,
Amana, Conroy, Middle Amana, Vinton Memorial Airport, Upper South
Amana, East Amana and High Amana.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1100 PM CST for southeastern,
northeastern and east central Iowa.

For your protection move to an interior room on the lowest floor of a
sturdy building.

&&

LAT...LON 4230 9208 4230 9184 4151 9183 4151 9211
TIME...MOT...LOC 0234Z 244DEG 50KT 4215 9185 4169 9183 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

McClure
637 
WWUS53 KDVN 160254
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
854 PM CST Wed Dec 15 2021

IAC011-095-160304-
/O.EXP.KDVN.SV.W.0114.000000T0000Z-211216T0300Z/
Benton IA-Iowa IA-
854 PM CST Wed Dec 15 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN BENTON AND EASTERN
IOWA COUNTIES WILL EXPIRE AT 900 PM CST...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with these thunderstorms.

A Tornado Watch remains in effect until 1100 PM CST for southeastern,
northeastern and east central Iowa.

LAT...LON 4230 9208 4230 9184 4151 9183 4151 9211
TIME...MOT...LOC 0254Z 270DEG 50KT 4227 9153 4181 9151 

$$

McClure

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 15, 7:17 PM CSTSevere Thunderstorm Warning Destructive damage threatDVNBenton, Iowa58 min
Dec 15, 7:31 PM CSTSevere Thunderstorm Warning Considerable damage threatDVNJefferson, Keokuk, Van Buren59 min
Dec 15, 7:33 PM CSTSevere Thunderstorm Warning Considerable damage threatDVNBuchanan57 min
Dec 15, 8:06 PM CSTTornado WarningDVNBenton, Buchanan20 min
Dec 15, 8:08 PM CSTSevere Thunderstorm Warning Considerable damage threatDVNBuchanan, Delaware, Johnson, Linn, Louisa, Washington67 min
Dec 15, 8:18 PM CSTSevere Thunderstorm Warning Considerable damage threatDVNHenry, Jefferson, Lee, Van Buren57 min
Dec 15, 8:34 PM CSTSevere Thunderstorm Warning Considerable damage threatDVNJefferson, Keokuk, Van Buren26 min
Dec 15, 8:44 PM CSTSevere Thunderstorm Warning Considerable damage threatDVNDelaware, Dubuque, Jones61 min
Dec 15, 8:50 PM CSTSevere Thunderstorm Warning Considerable damage threatDVNCedar, Louisa, Muscatine55 min
Dec 15, 8:53 PM CSTSevere Thunderstorm Warning Considerable damage threatDVNDes Moines, Lee67 min
Dec 15, 9:12 PM CSTSevere Thunderstorm Warning Considerable damage threatDVNClinton, Dubuque, Jackson, Scott63 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Every severe thunderstorm warning in 2021

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.