Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 103, NWS Quad Cities, IA
NWS Quad Cities, IA issued this severe thunderstorm warning at Aug 26, 2021, 10:43 PM CDT for Keokuk County, Washington County, Iowa. It was in force for 47 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
- Aug 26, 2021, 10:43 PM CDT (03:43 UTC)
- Expired
- Aug 26, 2021, 11:30 PM CDT
- In force
- 47 min
- Issued by
- NWS Quad Cities, IA
- Area
- Storm-based polygon
- Tornado
- Possible
- Damage threat
- Considerable
- Hail
- 1.75 in
- Wind
- 70.0 mph
Counties Keokuk County, IA, Washington County, IA
The radar
The Des Moines radar (KDMX), 136 km from the middle of the area, began a volume at 03:45 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 |
|---|---|---|---|
| Aug 26, 10:47 PM CDT | HAIL 1 | 1 Wnw Sigourney, IA | TIME ESTIMATED FROM RADAR, DELAYED REPORT. |
| Aug 26, 10:48 PM CDT | HAIL 1.75 | Sigourney, IA | . |
| Aug 26, 10:49 PM CDT | HAIL 1.5 | 2 N Sigourney, IA | MIX OF HAIL SIZES FROM PENNIES TO PING PONG BALL. |
| Aug 26, 10:51 PM CDT | TSTM WND DMG | Sigourney, IA | NUMEROUS 2.5 INCH TREE LIMBS DOWN ACROSS TOWN WITH TWO LARGE TREES DOWN. TIME OF THE EVENT ESTIMATED USING RADAR. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Davenport, (KDVN), launched 00:00Z, 3.7 hours before the alert went out and 144 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.
- Mixed-layer CAPE
- 673 J/kg
- Mixed-layer CIN
- -189 J/kg
- Mixed-layer LCL
- 1469 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- -106 m²/s²
- 0-3 km storm-relative helicity
- -64 m²/s²
- Significant tornado parameter
- -0.0
- Supercell composite
- -1.7
The text
As transmitted.
521
WUUS53 KDVN 270343
SVRDVN
IAC107-183-270430-
/O.NEW.KDVN.SV.W.0103.210827T0343Z-210827T0430Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
1043 PM CDT Thu Aug 26 2021
The National Weather Service in the Quad Cities has issued a
* Severe Thunderstorm Warning for...
Keokuk County in southeastern Iowa...
West central Washington County in southeastern Iowa...
* Until 1130 PM CDT.
* At 1042 PM CDT, severe thunderstorms were located along a line
extending from Harper to near Ottumwa, moving southeast at 20 mph.
HAZARD...Golf ball size hail and 70 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...People and animals outdoors will be injured. Expect hail
damage to roofs, siding, windows, and vehicles. Expect
considerable tree damage. Wind damage is also likely to
mobile homes, roofs, and outbuildings.
* Locations impacted include...
Richland.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
sturdy building.
These are dangerous storms, capable of producing large hail driven by
severe winds! SEEK SHELTER NOW inside a sturdy structure and stay
away from windows! If you are caught outdoors, cover your head and
neck.
Continuous cloud to ground lightning is occurring with these storms.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4137 9241 4151 9220 4151 9217 4138 9194
4117 9194 4116 9195 4116 9241
TIME...MOT...LOC 0342Z 330DEG 15KT 4134 9206 4107 9241
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH
$$
Gibbs2 follow-up statements
526
WWUS53 KDVN 270352
SVSDVN
Severe Weather Statement
National Weather Service Quad Cities IA/IL
1052 PM CDT Thu Aug 26 2021
IAC107-183-270430-
/O.CON.KDVN.SV.W.0103.000000T0000Z-210827T0430Z/
Keokuk IA-Washington IA-
1052 PM CDT Thu Aug 26 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 PM CDT
FOR KEOKUK AND WEST CENTRAL WASHINGTON COUNTIES...
At 1050 PM CDT, severe thunderstorms were located along a line
extending from near Harper to near Ottumwa, moving southeast at 15
mph.
THESE ARE DESTRUCTIVE STORMS FOR SIGOURNEY...LANCASTER...HAYESVILLE
...MARTINBURG... OLLIE...HENDRICK...AND HARPER...
HAZARD...80 mph wind gusts and golf ball size hail.
SOURCE...Trained weather spotters.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be heavily damaged. Expect
considerable damage to roofs, windows, and vehicles.
Extensive tree damage and power outages are likely.
Locations impacted include...
Sigourney, Hedrick, What Cheer, Richland, Delta, Keswick, South
English, Harper, Martinsburg, Hayesville, Keota, Ollie, Webster,
Lancaster, Keokuk County Expo, Pekin, Lake Belva Deer Park, Yenruogis
County Park and Talleyrand.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
These are potentially deadly storms. Seek shelter in an interior room
on the lowest floor of a well-built structure. Abandon vehicles in
search of a more substantial permanent structure. Stay away from
windows.
These are dangerous storms, capable of producing large hail driven by
severe winds! SEEK SHELTER NOW inside a sturdy structure and stay
away from windows! If you are caught outdoors, cover your head and
neck.
Continuous cloud to ground lightning is occurring with these storms.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4137 9241 4151 9220 4151 9217 4138 9194
4117 9194 4116 9195 4116 9241
TIME...MOT...LOC 0350Z 330DEG 15KT 4131 9204 4104 9239
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...OBSERVED
MAX HAIL SIZE...1.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...80 MPH
$$
Gibbs578
WWUS53 KDVN 270405
SVSDVN
Severe Weather Statement
National Weather Service Quad Cities IA/IL
1105 PM CDT Thu Aug 26 2021
IAC107-183-270430-
/O.CON.KDVN.SV.W.0103.000000T0000Z-210827T0430Z/
Keokuk IA-Washington IA-
1105 PM CDT Thu Aug 26 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 PM CDT
FOR KEOKUK AND WEST CENTRAL WASHINGTON COUNTIES...
At 1104 PM CDT, severe thunderstorms were located along a line
extending from near Harper to near Ottumwa, moving southeast at 20
mph.
THESE ARE DESTRUCTIVE STORMS FOR SIGOURNEY...LANCASTER...HAYESVILLE
...MARTINBURG... OLLIE...HENDRICK...AND HARPER...
HAZARD...80 mph wind gusts and golf ball size hail.
SOURCE...Trained weather spotters.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be heavily damaged. Expect
considerable damage to roofs, windows, and vehicles.
Extensive tree damage and power outages are likely.
Locations impacted include...
Sigourney, Hedrick, What Cheer, Richland, Delta, Keswick, South
English, Harper, Martinsburg, Hayesville, Keota, Ollie, Webster,
Lancaster, Keokuk County Expo, Pekin, Lake Belva Deer Park, Yenruogis
County Park and Talleyrand.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
These are potentially deadly storms. Seek shelter in an interior room
on the lowest floor of a well-built structure. Abandon vehicles in
search of a more substantial permanent structure. Stay away from
windows.
These are dangerous storms, capable of producing large hail driven by
severe winds! SEEK SHELTER NOW inside a sturdy structure and stay
away from windows! If you are caught outdoors, cover your head and
neck.
Continuous cloud to ground lightning is occurring with these storms.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4137 9241 4151 9220 4151 9217 4138 9194
4117 9194 4116 9195 4116 9241
TIME...MOT...LOC 0404Z 331DEG 18KT 4131 9197 4104 9232
TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...OBSERVED
MAX HAIL SIZE...1.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...80 MPH
$$
GibbsThe office that day
Everything else NWS Quad Cities, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 8:23 PM CDT | Special Weather Statement | DVN | Benton | 52 min |
| Aug 26, 9:21 PM CDT | Severe Thunderstorm Warning | DVN | Iowa, Keokuk | 39 min |
| Aug 26, 9:58 PM CDT | Severe Thunderstorm Warning | DVN | Keokuk | 47 min |
| Aug 26, 10:29 PM CDT | Flash Flood Warning | DVN | Keokuk | 4 hr |
| Aug 26, 10:57 PM CDT | Severe Thunderstorm Warning | DVN | Jefferson, Washington | 48 min |
| Aug 26, 11:20 PM CDT | Tornado Warning | DVN | Jefferson, Keokuk | 27 min |
| Aug 26, 11:39 PM CDT | Severe Thunderstorm Warning | DVN | Jefferson, Washington | 31 min |
| Aug 27, 1:34 PM CDT | Heat Advisory | DVN | Lee | 29 hr |
| Aug 27, 3:07 PM CDT | Heat Advisory | DVN | Des Moines, Henry, Van Buren | 28 hr |
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.