Alert archive / Iowa / Severe Thunderstorm Watches in 2024
Severe Thunderstorm Watch 421
The Storm Prediction Center issued this severe thunderstorm watch at Jun 15, 2024, 7:28 PM CDT for 36 counties in Iowa; 6 counties in Missouri. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 15, 2024, 7:28 PM CDT (00:28 UTC)
- Expired
- Jun 16, 2024, 2:00 AM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 65 kt
All 42 counties
Adair County, IA, Adams County, IA, Audubon County, IA, Boone County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Clay County, IA, Crawford County, IA, Dallas County, IA, Decatur County, IA, Dickinson County, IA, Greene County, IA, Guthrie County, IA, Hamilton County, IA, Hardin County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Marion County, IA, Marshall County, IA, Montgomery County, IA, Page County, IA, Pocahontas County, IA, Polk County, IA, Ringgold County, IA, Sac County, IA, Shelby County, IA, Story County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA, Webster County, IA, Andrew County, MO, Gentry County, MO, Harrison County, MO, Holt County, MO, Nodaway County, MO, Worth County, MO
The radar
The Des Moines radar (KDMX), 27 km from the middle of the area, began a volume at 00:30 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 15, 7:29 PM CDT | Severe Thunderstorm Warning | OAX | Fremont, Mills, Montgomery, Page, Pottawattamie | 46 min |
| Jun 15, 7:35 PM CDT | Severe Thunderstorm Warning | EAX | Atchison, Holt, Nodaway | 55 min |
| Jun 15, 7:50 PM CDT | Severe Thunderstorm Warning | OAX | Harrison, Pottawattamie, Shelby | 55 min |
| Jun 15, 7:56 PM CDT | Severe Thunderstorm Warning | OAX | Fremont, Mills, Montgomery, Page, Pottawattamie | 35 min |
| Jun 15, 8:01 PM CDT | Severe Thunderstorm Warning | OAX | Montgomery, Page, Pottawattamie | 45 min |
| Jun 15, 8:18 PM CDT | Severe Thunderstorm Warning | DMX | Adair, Adams, Cass, Taylor | 42 min |
| Jun 15, 8:28 PM CDT | Severe Thunderstorm Warning | EAX | Atchison, Holt, Nodaway | 47 min |
| Jun 15, 8:31 PM CDT | Severe Thunderstorm Warning | FSD | Clay, Dickinson, O'Brien, Osceola | 29 min |
| Jun 15, 9:25 PM CDT | Flash Flood Warning | EAX | Nodaway | 4 hr |
| Jun 15, 9:33 PM CDT | Flash Flood Warning | FSD | Dickinson | 2 hr |
| Jun 16, 1:34 AM CDT | Severe Thunderstorm Warning | DMX | Sac | 29 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 0.5 hours before the alert went out and 202 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
- 2168 J/kg
- Mixed-layer CIN
- -17 J/kg
- Mixed-layer LCL
- 848 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 323 m²/s²
- 0-3 km storm-relative helicity
- 532 m²/s²
- Significant tornado parameter
- 3.3
- Supercell composite
- 21.2
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 15, 7:47 PM CDT | Mesoscale Discussion | SPC | Monona, Woodbury | 88 min |
| Jun 15, 9:34 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Boone, Buena Vista, Calhoun and 32 more | 86 min |
| Jun 16, 1:47 AM CDT | Mesoscale Discussion | SPC | Audubon, Boone, Buena Vista, Calhoun, Carroll, Crawford and 15 more | 88 min |
| Jun 16, 12:33 PM CDT | Mesoscale Discussion | SPC | Louisa, Scott | 117 min |
| Jun 16, 2:15 PM CDT | Severe Thunderstorm Watch | SPC | Clinton, Jackson | 5 hr |
Nearby
Severe Thunderstorm Watches in Iowa, 2024Severe Thunderstorm Watches in Missouri, 2024Every severe thunderstorm watch in 2024
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.