Alert archive / Iowa / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 83, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Aug 9, 2021, 12:29 AM CDT for Boone County, Hamilton County, Webster County, Iowa. It was in force for 46 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
- Aug 9, 2021, 12:29 AM CDT (05:29 UTC)
- Expired
- Aug 9, 2021, 1:15 AM CDT
- In force
- 46 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Tornado
- Possible
- Hail
- 1.0 in
- Wind
- 60.0 mph
Counties Boone County, IA, Hamilton County, IA, Webster County, IA
The radar
The Des Moines radar (KDMX), 58 km from the middle of the area, began a volume at 05:30 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 nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 5.5 hours before the alert went out and 221 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
- 1733 J/kg
- Mixed-layer CIN
- -130 J/kg
- Mixed-layer LCL
- 1356 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 104 m²/s²
- 0-3 km storm-relative helicity
- 137 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 6.0
The text
As transmitted.
778
WUUS53 KDMX 090529
SVRDMX
IAC015-079-187-090615-
/O.NEW.KDMX.SV.W.0083.210809T0529Z-210809T0615Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
1229 AM CDT Mon Aug 9 2021
The National Weather Service in Des Moines has issued a
* Severe Thunderstorm Warning for...
Southeastern Webster County in central Iowa...
North central Boone County in central Iowa...
Southwestern Hamilton County in central Iowa...
* Until 115 AM CDT.
* At 1228 AM CDT, a severe thunderstorm was located 13 miles east of
Gowrie, or 15 miles northwest of Boone, moving southeast at 15 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage
to roofs, siding, and trees.
* This severe thunderstorm will remain over mainly rural areas of
southeastern Webster, north central Boone and southwestern Hamilton
Counties, including the following locations... Stratford, Pilot
Mound, Fraser and Dayton.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4222 9410 4230 9404 4225 9380 4207 9390
TIME...MOT...LOC 0528Z 294DEG 12KT 4224 9403
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Ansorge4 follow-up statements
284
WWUS53 KDMX 090550
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
1250 AM CDT Mon Aug 9 2021
IAC015-079-187-090615-
/O.CON.KDMX.SV.W.0083.000000T0000Z-210809T0615Z/
Webster IA-Boone IA-Hamilton IA-
1250 AM CDT Mon Aug 9 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 AM CDT
FOR SOUTHEASTERN WEBSTER...NORTH CENTRAL BOONE AND SOUTHWESTERN
HAMILTON COUNTIES...
At 1250 AM CDT, a severe thunderstorm was located 8 miles northwest
of Boone, moving southeast at 15 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage to
roofs, siding, and trees.
Locations impacted include...
Pilot Mound and Fraser.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4220 9408 4226 9400 4224 9381 4207 9390
TIME...MOT...LOC 0550Z 310DEG 13KT 4216 9396
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Ansorge743 WWUS53 KDMX 090559 SVSDMX Severe Weather Statement National Weather Service Des Moines IA 1259 AM CDT Mon Aug 9 2021 IAC015-079-187-090615- /O.CON.KDMX.SV.W.0083.000000T0000Z-210809T0615Z/ Webster IA-Boone IA-Hamilton IA- 1259 AM CDT Mon Aug 9 2021 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 AM CDT FOR SOUTHEASTERN WEBSTER...NORTH CENTRAL BOONE AND SOUTHWESTERN HAMILTON COUNTIES... At 1259 AM CDT, a severe thunderstorm was located 7 miles northwest of Boone, moving southeast at 10 mph. HAZARD...Quarter size hail. SOURCE...Radar indicated. IMPACT...Damage to vehicles is expected. Locations impacted include... Pilot Mound and Fraser. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. && LAT...LON 4218 9405 4221 9402 4221 9383 4207 9390 TIME...MOT...LOC 0559Z 321DEG 9KT 4214 9395 TORNADO...POSSIBLE HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...1.00 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...<50 MPH $$ Ansorge
739
WWUS53 KDMX 090602
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
102 AM CDT Mon Aug 9 2021
IAC079-187-090612-
/O.CAN.KDMX.SV.W.0083.000000T0000Z-210809T0615Z/
Webster IA-Hamilton IA-
102 AM CDT Mon Aug 9 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN WEBSTER AND
SOUTHWESTERN HAMILTON COUNTIES IS CANCELLED...
The severe thunderstorm which prompted the warning has moved out of
the warned area. Therefore, the warning has been cancelled.
LAT...LON 4216 9402 4220 9400 4220 9383 4207 9390
TIME...MOT...LOC 0602Z 312DEG 11KT 4214 9394
$$
IAC015-090615-
/O.CON.KDMX.SV.W.0083.000000T0000Z-210809T0615Z/
Boone IA-
102 AM CDT Mon Aug 9 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 AM CDT
FOR NORTH CENTRAL BOONE COUNTY...
At 102 AM CDT, a severe thunderstorm was located near Boone, moving
southeast at 10 mph.
HAZARD...Quarter size hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.
Locations impacted include...
Pilot Mound and Fraser.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4216 9402 4220 9400 4220 9383 4207 9390
TIME...MOT...LOC 0602Z 312DEG 11KT 4214 9394
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH
$$
Ansorge252
WWUS53 KDMX 090615
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
115 AM CDT Mon Aug 9 2021
IAC015-090625-
/O.EXP.KDMX.SV.W.0083.000000T0000Z-210809T0615Z/
Boone IA-
115 AM CDT Mon Aug 9 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL BOONE COUNTY HAS
EXPIRED...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been allowed to expire. However small
hail is still possible with this thunderstorm.
LAT...LON 4216 9402 4220 9400 4220 9383 4207 9390
TIME...MOT...LOC 0615Z 294DEG 12KT 4213 9390
$$
AnsorgeThe office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 8:36 PM CDT | Tornado Warning | DMX | Pocahontas | 24 min |
| Aug 8, 9:02 PM CDT | Tornado Warning | DMX | Calhoun, Pocahontas | 31 min |
| Aug 8, 10:39 PM CDT | Special Weather Statement | DMX | Webster | 51 min |
| Aug 8, 11:00 PM CDT | Tornado Warning | DMX | Webster | 30 min |
| Aug 8, 11:30 PM CDT | Tornado Warning | DMX | Webster | 30 min |
| Aug 8, 11:52 PM CDT | Tornado Warning | DMX | Boone, Webster | 38 min |
| Aug 9, 12:23 AM CDT | Tornado Warning | DMX | Butler, Franklin | 20 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.