Alert archive / Iowa / Tornado Warnings in 2021
Tornado Warning 30, NWS Des Moines, IA
NWS Des Moines, IA issued this tornado warning at Aug 8, 2021, 11:52 PM CDT for Boone County, Webster County, Iowa. It was in force for 38 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 8, 2021, 11:52 PM CDT (04:52 UTC)
- Expired
- Aug 9, 2021, 12:30 AM CDT
- In force
- 38 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 0.75 in
Counties Boone County, IA, Webster County, IA
The radar
The Des Moines radar (KDMX), 66 km from the middle of the area, began a volume at 04:52 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, 4.9 hours before the alert went out and 212 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.
899
WFUS53 KDMX 090452
TORDMX
IAC015-187-090530-
/O.NEW.KDMX.TO.W.0030.210809T0452Z-210809T0530Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
1152 PM CDT Sun Aug 8 2021
The National Weather Service in Des Moines has issued a
* Tornado Warning for...
Southeastern Webster County in central Iowa...
Northwestern Boone County in central Iowa...
* Until 1230 AM CDT.
* At 1151 PM CDT, a severe thunderstorm capable of producing a
tornado was located near Gowrie, or 14 miles south of Fort Dodge,
moving southeast at 20 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* This tornadic thunderstorm will remain over mainly rural areas of
southeastern Webster and northwestern Boone Counties, including the
following locations... Boxholm, Harcourt, Pilot Mound and Dayton.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4235 9415 4220 9391 4211 9411 4220 9417
4221 9416 4221 9418 4231 9424
TIME...MOT...LOC 0451Z 312DEG 17KT 4231 9417
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Cogil2 follow-up statements
204
WWUS53 KDMX 090508
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
1208 AM CDT Mon Aug 9 2021
IAC015-187-090530-
/O.CON.KDMX.TO.W.0030.000000T0000Z-210809T0530Z/
Webster IA-Boone IA-
1208 AM CDT Mon Aug 9 2021
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1230 AM CDT FOR
SOUTHEASTERN WEBSTER AND NORTHWESTERN BOONE COUNTIES...
At 1208 AM CDT, a severe thunderstorm capable of producing a tornado
was located 8 miles east of Gowrie, or 17 miles south of Fort Dodge,
moving southeast at 15 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
Locations impacted include...
Dayton, Harcourt, Boxholm and Pilot Mound.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4220 9391 4211 9411 4219 9416 4221 9416
4228 9420 4232 9410
TIME...MOT...LOC 0508Z 315DEG 14KT 4226 9412
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Cogil353
WWUS53 KDMX 090531
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
1231 AM CDT Mon Aug 9 2021
IAC015-187-090540-
/O.EXP.KDMX.TO.W.0030.000000T0000Z-210809T0530Z/
Webster IA-Boone IA-
1231 AM CDT Mon Aug 9 2021
...THE TORNADO WARNING FOR SOUTHEASTERN WEBSTER AND NORTHWESTERN
BOONE COUNTIES HAS EXPIRED...
The tornado threat has diminished and the Tornado Warning has been
cancelled. However, large hail and damaging winds remain likely and
a Severe Thunderstorm Warning remains in effect for portions of
southeast Webster, southwest Hamilton and northern central Boone
counties until 115 AM...
LAT...LON 4220 9391 4211 9411 4219 9416 4221 9416
4228 9420 4232 9410
TIME...MOT...LOC 0530Z 312DEG 17KT 4220 9403
$$
CogilThe 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 9, 12:23 AM CDT | Tornado Warning | DMX | Butler, Franklin | 20 min |
| Aug 9, 12:29 AM CDT | Severe Thunderstorm Warning | DMX | Boone, Hamilton, Webster | 46 min |
Nearby
Tornado Warnings in Iowa, 2021Every tornado warning in 2021Tornadoes 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.