Alert archive / Iowa / Severe Thunderstorm Watches in 2024
Severe Thunderstorm Watch 577
The Storm Prediction Center issued this severe thunderstorm watch at Jul 31, 2024, 3:46 AM CDT for 6 counties in Illinois; 11 counties in Iowa; 4 counties in Missouri. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 31, 2024, 3:46 AM CDT (08:46 UTC)
- Expired
- Jul 31, 2024, 9:00 AM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 21 counties
Des Moines County, IA, Henry County, IA, Iowa County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Muscatine County, IA, Van Buren County, IA, Washington County, IA, Adams County, IL, Hancock County, IL, Henderson County, IL, McDonough County, IL, Mercer County, IL, Warren County, IL, Clark County, MO, Knox County, MO, Lewis County, MO, Scotland County, MO
The radar
The Quad Cities radar (KDVN), 106 km from the middle of the area, began a volume at 08:49 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
- 10%
- One or more EF2 to EF5 tornadoes
- 10%
- Ten or more severe wind reports
- 60%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 90%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 31, 4:03 AM CDT | Severe Thunderstorm Warning | DVN | Jefferson, Van Buren | 42 min |
| Jul 31, 4:43 AM CDT | Severe Thunderstorm Warning | DVN | Lee, Van Buren | 47 min |
| Jul 31, 4:45 AM CDT | Flash Flood Warning | DVN | Jefferson, Keokuk, Van Buren | 6 hr |
| Jul 31, 5:28 AM CDT | Severe Thunderstorm Warning | DVN | Hancock, Henderson, McDonough, Warren | 62 min |
| Jul 31, 5:35 AM CDT | Severe Thunderstorm Warning | LSX | Adams | 40 min |
| Jul 31, 6:12 AM CDT | Severe Thunderstorm Warning | LSX | Adams, Brown | 48 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
Davenport, (KDVN), launched 00:00Z, 8.8 hours before the alert went out and 112 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
- 111 J/kg
- Mixed-layer CIN
- -476 J/kg
- Mixed-layer LCL
- 1513 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 158 m²/s²
- 0-3 km storm-relative helicity
- 187 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 31, 2:31 AM CDT | Mesoscale Discussion | SPC | Adams, Hancock, Henderson, McDonough | 119 min |
| Jul 31, 5:30 AM CDT | Mesoscale Discussion | SPC | Adams, Brown, Cass, Christian, Fulton, Hancock and 12 more | 2 hr |
| Jul 31, 5:50 AM CDT | Severe Thunderstorm Watch | SPC | Bond, Brown, Calhoun, Cass, Champaign, Christian and 37 more | 6 hr |
| Jul 31, 9:56 AM CDT | Mesoscale Discussion | SPC | Edgar, Vermilion | 94 min |
| Jul 31, 11:01 AM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Greene, Hancock, Pike and 1 more | 89 min |
| Jul 31, 12:19 PM CDT | Mesoscale Discussion | SPC | Clark, Crawford, Cumberland, Edgar, Edwards, Jasper and 3 more | 116 min |
| Jul 31, 12:57 PM CDT | Severe Thunderstorm Watch | SPC | Edwards, Gallatin, Wabash, White | 6 hr |
| Jul 30, 11:17 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Boone, Carroll, Cass and 19 more | 118 min |
| Jul 30, 11:54 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Appanoose, Audubon, Boone, Calhoun and 37 more | 7 hr |
| Jul 31, 3:00 PM CDT | Severe Thunderstorm Watch | SPC | Fremont, Harrison, Mills, Pottawattamie | 7 hr |
| Jul 31, 5:12 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Cass, Clarke, Dallas and 12 more | 2 hr |
| Jul 31, 6:04 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Carroll, Cass, Crawford and 8 more | 56 min |
| Jul 31, 6:19 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Appanoose, Audubon, Boone, Carroll and 28 more | 6 hr |
| Jul 31, 6:56 PM CDT | Mesoscale Discussion | SPC | Lyon, Osceola | 2 hr |
Nearby
Severe Thunderstorm Watches in Iowa, 2024Severe Thunderstorm Watches in Illinois, 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.