Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 101, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Aug 26, 2021, 8:47 PM CDT for Mahaska County, Poweshiek County, Iowa. It was in force for 58 min. 3 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, 8:47 PM CDT (01:47 UTC)
- Expired
- Aug 26, 2021, 9:45 PM CDT
- In force
- 58 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Hail
- 0.88 in
- Wind
- 60.0 mph
Counties Mahaska County, IA, Poweshiek County, IA
The radar
The Des Moines radar (KDMX), 104 km from the middle of the area, began a volume at 01:48 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 26, 8:58 PM CDT | TSTM WND GST 63 | 5 Ene Searsboro, IA | MEASURED VIA PERSONAL WEATHER STATION. |
| Aug 26, 9:00 PM CDT | TSTM WND DMG | Montezuma, IA | TREES DOWN. DAMAGE TO OUTBUILDINGS. TIME ESTIMATED FROM RADAR. |
| Aug 26, 9:00 PM CDT | TSTM WND GST 58 | 2 Nw Montezuma, IA | SMALL TREE LIMBS DOWN. MEASURED BY PERSONAL WEATHER STATION. TIME ESTIMATED BY 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, 1.8 hours before the alert went out and 165 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.
830
WUUS53 KDMX 270147
SVRDMX
IAC123-157-270245-
/O.NEW.KDMX.SV.W.0101.210827T0147Z-210827T0245Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
847 PM CDT Thu Aug 26 2021
The National Weather Service in Des Moines has issued a
* Severe Thunderstorm Warning for...
Poweshiek County in central Iowa...
Northeastern Mahaska County in south central Iowa...
* Until 945 PM CDT.
* At 846 PM CDT, a severe thunderstorm was located over Montezuma,
moving southeast at 20 mph.
HAZARD...60 mph wind gusts and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* This severe thunderstorm will remain over mainly rural areas of
Poweshiek and northeastern Mahaska Counties, including the
following locations... Guernsey, Searsboro, Malcom, Barnes City,
Deep River and Rose Hill.
This includes Interstate 80 between mile markers 185 and 204.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4151 9241 4125 9241 4154 9276 4160 9276
4184 9255 4170 9230 4151 9230
TIME...MOT...LOC 0146Z 302DEG 18KT 4159 9252
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Krull3 follow-up statements
148
WWUS53 KDMX 270205
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
905 PM CDT Thu Aug 26 2021
IAC123-157-270245-
/O.CON.KDMX.SV.W.0101.000000T0000Z-210827T0245Z/
Poweshiek IA-Mahaska IA-
905 PM CDT Thu Aug 26 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 945 PM CDT
FOR POWESHIEK AND NORTHEASTERN MAHASKA COUNTIES...
At 904 PM CDT, a severe thunderstorm was located near Montezuma,
moving southeast at 30 mph.
HAZARD...60 mph wind gusts and nickel size hail.
SOURCE...Personal Weather Station near Montezuma recorded at 63 MPH
gust.
IMPACT...Expect damage to roofs, siding, and trees.
Locations impacted include...
Montezuma, Brooklyn, New Sharon, Malcom, Deep River, Barnes City,
Rose Hill, Searsboro and Guernsey.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4151 9241 4125 9241 4154 9276 4160 9276
4184 9255 4170 9230 4151 9230
TIME...MOT...LOC 0204Z 300DEG 26KT 4156 9246
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH
$$
Krull086
WWUS53 KDMX 270222
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
922 PM CDT Thu Aug 26 2021
IAC123-157-270245-
/O.CON.KDMX.SV.W.0101.000000T0000Z-210827T0245Z/
Poweshiek IA-Mahaska IA-
922 PM CDT Thu Aug 26 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 945 PM CDT
FOR SOUTHERN POWESHIEK AND NORTHEASTERN MAHASKA COUNTIES...
At 921 PM CDT, a severe thunderstorm was located 7 miles northwest of
Keswick, or 9 miles southeast of Montezuma, moving southeast at 20
mph.
HAZARD...60 mph wind gusts and nickel size hail.
SOURCE...A personal weather station in Montezuma reported a 63 MPH
gust around 858 PM CDT.
IMPACT...Expect damage to roofs, siding, and trees.
Locations impacted include...
Montezuma, New Sharon, Deep River, Barnes City, Rose Hill, Searsboro
and Guernsey.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4151 9241 4125 9241 4154 9276 4160 9276
4170 9257 4170 9230 4151 9230
TIME...MOT...LOC 0221Z 302DEG 18KT 4151 9236
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH
$$
Krull110
WWUS53 KDMX 270241
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
941 PM CDT Thu Aug 26 2021
IAC123-157-270251-
/O.EXP.KDMX.SV.W.0101.000000T0000Z-210827T0245Z/
Poweshiek IA-Mahaska IA-
941 PM CDT Thu Aug 26 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN POWESHIEK AND
NORTHEASTERN MAHASKA COUNTIES WILL EXPIRE AT 945 PM CDT...
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire. However gusty
winds and heavy rain are still possible with this thunderstorm.
LAT...LON 4151 9241 4125 9241 4154 9276 4160 9276
4170 9257 4170 9230 4151 9230
TIME...MOT...LOC 0241Z 302DEG 18KT 4146 9225
$$
KrullThe office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 7:02 PM CDT | Severe Thunderstorm Warning | DMX | Audubon, Carroll | 28 min |
| Aug 26, 8:35 PM CDT | Special Weather Statement | DMX | Poweshiek | 40 min |
| Aug 26, 9:46 PM CDT | Special Weather Statement | DMX | Mahaska | 44 min |
| Aug 26, 10:26 PM CDT | Special Weather Statement | DMX | Mahaska | 34 min |
| Aug 26, 10:30 PM CDT | Severe Thunderstorm Warning | DMX | Emmet, Palo Alto | 45 min |
| Aug 26, 10:52 PM CDT | Special Weather Statement | DMX | Wapello | 38 min |
| Aug 26, 11:42 PM CDT | Severe Thunderstorm Warning | DMX | Emmet, Palo Alto | 33 min |
| Aug 27, 12:13 AM CDT | Special Weather Statement | DMX | Emmet | 32 min |
| Aug 27, 2:08 PM CDT | Special Weather Statement | DMX | Hancock | 37 min |
| Aug 27, 2:59 PM CDT | Special Weather Statement | DMX | Cerro Gordo | 16 min |
| Aug 27, 4:23 PM CDT | Severe Thunderstorm Warning | DMX | Cerro Gordo, Hancock | 52 min |
| Aug 27, 4:48 PM CDT | Tornado Warning | DMX | Cerro Gordo, Hancock | 57 min |
| Aug 27, 4:58 PM CDT | Severe Thunderstorm Warning | DMX | Cerro Gordo, Franklin, Hancock | 32 min |
| Aug 27, 5:23 PM CDT | Tornado Warning | DMX | Cerro Gordo | 37 min |
| Aug 27, 5:25 PM CDT | Tornado Warning | DMX | Cerro Gordo | 35 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.