Alert archive / Iowa / Severe Thunderstorm Watches in 2014
Severe Thunderstorm Watch 484
The Storm Prediction Center issued this severe thunderstorm watch at Aug 31, 2014, 9:45 PM CDT for 33 counties in Iowa; 4 counties in Wisconsin. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 31, 2014, 9:45 PM CDT (02:45 UTC)
- Expired
- Sep 1, 2014, 2:14 AM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 65 kt
All 37 counties
Allamakee County, IA, Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Buchanan County, IA, Cedar County, IA, Clayton County, IA, Clinton County, IA, Davis County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Fayette County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Mahaska County, IA, Monroe County, IA, Muscatine County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Winneshiek County, IA, Crawford County, WI, Grant County, WI, Richland County, WI, Vernon County, WI
The radar
The Quad Cities radar (KDVN), 115 km from the middle of the area, began a volume at 02:47 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.
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
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 60%
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 |
|---|---|---|---|---|
| Aug 31, 9:55 PM CDT | Severe Thunderstorm Warning | DMX | Black Hawk, Bremer, Butler, Grundy, Tama | 50 min |
| Aug 31, 10:09 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Mahaska, Marion, Warren | 51 min |
| Aug 31, 10:20 PM CDT | Severe Thunderstorm Warning | DVN | Benton, Buchanan, Delaware, Linn | 55 min |
| Aug 31, 10:30 PM CDT | Severe Thunderstorm Warning | ARX | Fayette | 48 min |
| Aug 31, 11:49 PM CDT | Severe Thunderstorm Warning | DMX | Mahaska, Monroe, Wapello | 41 min |
| Sep 1, 12:19 AM CDT | Severe Thunderstorm Warning | DVN | Iowa, Johnson, Keokuk, Louisa, Washington | 41 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, 2.8 hours before the alert went out and 121 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
- 1371 J/kg
- Mixed-layer CIN
- -53 J/kg
- Mixed-layer LCL
- 1420 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 69 m²/s²
- 0-3 km storm-relative helicity
- 56 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 |
|---|---|---|---|---|
| Aug 31, 7:12 PM CDT | Tornado Watch | SPC | Adair, Adams, Audubon, Boone, Calhoun, Carroll and 25 more | 6 hr |
| Aug 31, 9:09 PM CDT | Mesoscale Discussion | SPC | Allamakee, Appanoose, Benton, Black Hawk, Bremer, Buchanan and 39 more | 96 min |
Nearby
Severe Thunderstorm Watches in Iowa, 2014Severe Thunderstorm Watches in Wisconsin, 2014Every severe thunderstorm watch in 2014
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.