Alert archive / Iowa / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 117
The Storm Prediction Center issued this severe thunderstorm watch at Mar 29, 2012, 8:30 PM CDT for 15 counties in Iowa; 11 counties in Missouri. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 29, 2012, 8:30 PM CDT (01:30 UTC)
- Expired
- Mar 30, 2012, 2:00 AM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 26 counties
Adair County, IA, Adams County, IA, Appanoose County, IA, Cass County, IA, Clarke County, IA, Decatur County, IA, Lucas County, IA, Madison County, IA, Marion County, IA, Monroe County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Linn County, MO, Livingston County, MO, Mercer County, MO, Putnam County, MO, Sullivan County, MO, Worth County, MO
The radar
The Des Moines radar (KDMX), 90 km from the middle of the area, began a volume at 01:33 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
- 10%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 29, 8:49 PM CDT | Severe Thunderstorm Warning | DMX | Taylor | 44 min |
| Mar 29, 9:49 PM CDT | Severe Thunderstorm Warning | DMX | Ringgold, Taylor | 41 min |
| Mar 29, 10:49 PM CDT | Severe Thunderstorm Warning | DMX | Decatur, Ringgold | 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
Omaha, NE (KOAX), launched 00:00Z, 1.5 hours before the alert went out and 221 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
- 761 J/kg
- Mixed-layer CIN
- -64 J/kg
- Mixed-layer LCL
- 647 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 76 m²/s²
- 0-3 km storm-relative helicity
- 99 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 2.5
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 29, 7:55 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Appanoose, Cass, Clarke, Dallas and 12 more | 65 min |
| Mar 29, 9:51 PM CDT | Mesoscale Discussion | SPC | Fremont, Mills, Montgomery, Page | 54 min |
| Mar 29, 11:50 PM CDT | Mesoscale Discussion | SPC | Appanoose, Clarke, Decatur, Lucas, Madison, Mahaska and 6 more | 55 min |
| Mar 30, 3:20 PM CDT | Mesoscale Discussion | SPC | Adams, Audubon, Cass, Crawford, Fremont, Harrison and 7 more | 85 min |
Nearby
Severe Thunderstorm Watches in Iowa, 2012Severe Thunderstorm Watches in Missouri, 2012Every severe thunderstorm watch in 2012
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.