Alert archive / Iowa / Flash Flood Warnings in 2023
Flash Flood Warning 12, NWS Omaha, NE
NWS Omaha, NE issued this flash flood warning at Aug 2, 2023, 2:47 AM CDT for Harrison County, Pottawattamie County, Shelby County, Iowa. It was in force for 8 hr. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 2, 2023, 2:47 AM CDT (07:47 UTC)
- Expired
- Aug 2, 2023, 10:21 AM CDT
- In force
- 8 hr
- Issued by
- NWS Omaha, NE
- Area
- Storm-based polygon
- Flood severity
- None
Counties Harrison County, IA, Pottawattamie County, IA, Shelby County, IA
The radar
The Omaha radar (KOAX), 73 km from the middle of the area, began a volume at 07:47 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, 7.8 hours before the alert went out and 73 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
- 1026 J/kg
- Mixed-layer CIN
- -186 J/kg
- Mixed-layer LCL
- 775 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 66 m²/s²
- 0-3 km storm-relative helicity
- 185 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.9
What forecasters said that day
The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Omaha, NE wrote its last area forecast discussion before this flash flood warning went out at Aug 2, 12:00 AM CDT, 2 hours 47 minutes earlier.
Area forecast discussion, Aug 2, 12:00 AM CDT, 2 hours 47 minutes before
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</html>In the hours before
Special weather statement, Aug 2, 1:59 AM CDT, 48 minutes before
Special Weather Statement
National Weather Service Omaha/Valley Nebraska
159 AM CDT Wed Aug 2 2023
IAZ069-020715-
Pottawattamie IA-
159 AM CDT Wed Aug 2 2023
...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL POTTAWATTAMIE
COUNTY THROUGH 215 AM CDT...
At 159 AM CDT, Doppler radar was tracking a strong thunderstorm 8
miles south of Walnut, or 8 miles west of Atlantic, moving east at 10
mph.
HAZARD...Nickel size hail.
SOURCE...Radar indicated.
IMPACT...Minor hail damage to vegetation is possible.
This storm will remain over mainly rural areas of east central
Pottawattamie County.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4128 9528 4146 9527 4147 9516 4139 9515
4126 9516
TIME...MOT...LOC 0659Z 271DEG 8KT 4137 9518
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...<30 MPH
DeWaldSpecial weather statement, Aug 2, 2:04 AM CDT, 43 minutes before
Special Weather Statement
National Weather Service Omaha/Valley Nebraska
204 AM CDT Wed Aug 2 2023
IAZ069-020715-
Pottawattamie IA-
204 AM CDT Wed Aug 2 2023
...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL POTTAWATTAMIE
COUNTY THROUGH 215 AM CDT...
At 203 AM CDT, Doppler radar was tracking a strong thunderstorm near
Minden, or 18 miles southwest of Harlan, moving east at 25 mph.
HAZARD...Winds in excess of 30 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down small tree branches and blow
around unsecured objects. Minor hail damage to vegetation
is possible.
Locations impacted include...
Neola, Shelby, Minden, and Arrowhead Park.
This includes Interstate 80 in Iowa between mile markers 20 and 34.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4137 9564 4150 9565 4150 9540 4137 9540
TIME...MOT...LOC 0703Z 264DEG 20KT 4143 9554
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...30 MPH
DeWaldSpecial weather statement, Aug 2, 2:06 AM CDT, 41 minutes before
Special Weather Statement
National Weather Service Omaha/Valley Nebraska
206 AM CDT Wed Aug 2 2023
IAZ055-069-NEZ045-020715-
Pottawattamie IA-Harrison IA-Washington NE-
206 AM CDT Wed Aug 2 2023
...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN POTTAWATTAMIE...
SOUTHWESTERN HARRISON AND SOUTHEASTERN WASHINGTON COUNTIES THROUGH
215 AM CDT...
At 206 AM CDT, Doppler radar was tracking a strong thunderstorm 3
miles southwest of Missouri Valley, or 9 miles east of Blair, moving
southeast at 25 mph.
HAZARD...Winds in excess of 30 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down small tree branches and blow
around unsecured objects. Minor hail damage to vegetation
is possible.
Locations impacted include...
Missouri Valley, Fort Calhoun, Modale, Desoto Bend National Wildlife
Refuge, Wilson Island State Park, and Historical Village Welcome
Center.
This includes Interstate 29 between mile markers 68 and 79.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4145 9607 4162 9606 4161 9578 4144 9579
TIME...MOT...LOC 0706Z 294DEG 20KT 4153 9595
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...30 MPH
DeWaldThe office that day
Everything else NWS Omaha, NE issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 2, 2:12 AM CDT | Severe Thunderstorm Warning | OAX | Washington | 48 min |
| Aug 2, 6:14 AM CDT | Severe Thunderstorm Warning | OAX | Madison, Pierce, Stanton, Thurston, Wayne | 31 min |
| Aug 2, 6:23 AM CDT | Flash Flood Warning | OAX | Burt | 4 hr |
| Aug 2, 6:31 AM CDT | Severe Thunderstorm Warning | OAX | Burt, Cuming, Stanton, Thurston, Wayne | 29 min |
| Aug 2, 6:33 AM CDT | Areal Flood Advisory | OAX | Burt, Colfax, Cuming, Dodge, Stanton, Thurston and 1 more | 3 hr |
| Aug 2, 6:40 AM CDT | Severe Thunderstorm Warning | OAX | Thurston, Wayne | 35 min |
| Aug 2, 6:48 AM CDT | Areal Flood Advisory | OAX | Dodge | 101 min |
| Aug 2, 6:55 AM CDT | Severe Thunderstorm Warning | OAX | Burt, Cuming, Thurston, Wayne | 39 min |
| Aug 2, 7:17 AM CDT | Flash Flood Warning | OAX | Burt | 3 hr |
| Aug 2, 7:27 AM CDT | Flash Flood Warning | OAX | Burt, Washington | 3 hr |
| Aug 2, 7:57 AM CDT | Areal Flood Advisory | OAX | Douglas, Sarpy, Washington | 3 hr |
| Aug 2, 8:14 AM CDT | Areal Flood Advisory | OAX | Dodge, Douglas, Washington | 104 min |
| Aug 2, 10:20 AM CDT | Areal Flood Warning | OAX | Burt, Dodge, Washington | 3 hr |
| Aug 2, 1:59 AM CDT | Special Weather Statement | OAX | Cass | 16 min |
| Aug 2, 2:04 AM CDT | Special Weather Statement | OAX | Pottawattamie | 11 min |
| Aug 2, 2:06 AM CDT | Special Weather Statement | OAX | Harrison | 9 min |
| Aug 2, 2:26 AM CDT | Severe Thunderstorm Warning | OAX | Harrison, Pottawattamie, Shelby | 37 min |
| Aug 2, 4:45 AM CDT | Flash Flood Warning | OAX | Harrison, Shelby | 6 hr |
Nearby
Flash Flood Warnings in Iowa, 2023Every flash flood warning in 2023
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.