Alert archive / Iowa / Special Weather Statements in 2021
Special Weather Statement, NWS Des Moines, IA
NWS Des Moines, IA issued this special weather statement at Aug 8, 2021, 3:11 AM CDT for Black Hawk County, Iowa. It was in force for 64 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, 3:11 AM CDT (08:11 UTC)
- Expired
- Aug 8, 2021, 4:15 AM CDT
- In force
- 64 min
- Issued by
- NWS Des Moines, IA
- Hail
- 0.25 in
- Wind
- 30
County Black Hawk County, IA
The radar
The Des Moines radar (KDMX), 146 km from the middle of the area, began a volume at 08:14 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
Davenport, (KDVN), launched 00:00Z, 8.2 hours before the alert went out and 177 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
- 2231 J/kg
- Mixed-layer CIN
- -18 J/kg
- Mixed-layer LCL
- 1094 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 88 m²/s²
- 0-3 km storm-relative helicity
- 163 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 4.1
The text
As transmitted.
111
WWUS83 KDMX 080811
SPSDMX
Special Weather Statement
National Weather Service Des Moines IA
311 AM CDT Sun Aug 8 2021
IAZ027-028-038-039-080915-
Black Hawk IA-Bremer IA-Grundy IA-Butler IA-
311 AM CDT Sun Aug 8 2021
...Strong thunderstorms will impact portions of Black Hawk, southern
Bremer, northeastern Grundy and eastern Butler Counties through 415
AM CDT...
At 311 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Shell Rock to near Waterloo to near
Fairbank. Movement was north at 15 mph.
HAZARD...Winds in excess of 30 mph and pea size hail. The Waterloo
airport had a recent wind gust to 37 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Strong thunderstorms will be near...
Shell Rock around 325 AM CDT.
Other locations in the path of these storms include Waverly,
Clarksville and Denver.
This includes Interstate 380 between mile markers 56 and 73.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4230 9207 4230 9253 4238 9275 4284 9268
4269 9227 4270 9208 4247 9208 4247 9206
TIME...MOT...LOC 0811Z 186DEG 12KT 4268 9265 4252 9230 4256 9204
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...30 MPH
$$
AnsorgeThe office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 12:03 AM CDT | Special Weather Statement | DMX | Adams, Taylor | 57 min |
| Aug 8, 12:26 AM CDT | Special Weather Statement | DMX | Greene | 49 min |
| Aug 8, 12:45 AM CDT | Special Weather Statement | DMX | Greene | 30 min |
| Aug 8, 12:51 AM CDT | Special Weather Statement | DMX | Decatur, Ringgold, Union | 54 min |
| Aug 8, 1:20 AM CDT | Special Weather Statement | DMX | Tama | 55 min |
| Aug 8, 1:29 AM CDT | Special Weather Statement | DMX | Clarke, Decatur, Lucas, Wayne | 46 min |
| Aug 8, 1:41 AM CDT | Special Weather Statement | DMX | Story | 49 min |
| Aug 8, 2:03 AM CDT | Special Weather Statement | DMX | Grundy, Hardin | 42 min |
| Aug 8, 2:24 AM CDT | Special Weather Statement | DMX | Black Hawk | 51 min |
| Aug 8, 3:39 PM CDT | Heat Advisory | DMX | Adair, Adams, Appanoose, Black Hawk, Boone, Bremer and 26 more | 51 hr |
Nearby
Special Weather Statements in Iowa, 2021Every special weather statement 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.