Alert archive / Iowa / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 283
The Storm Prediction Center issued this severe thunderstorm watch at May 19, 2012, 6:52 PM CDT for 23 counties in Iowa; Dakota County, Nebraska. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 19, 2012, 6:52 PM CDT (23:52 UTC)
- Expired
- May 19, 2012, 11:52 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 24 counties
Adair County, IA, Audubon County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cherokee County, IA, Clay County, IA, Crawford County, IA, Dickinson County, IA, Emmet County, IA, Greene County, IA, Guthrie County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, O'Brien County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sac County, IA, Webster County, IA, Woodbury County, IA, Dakota County, NE
The radar
The Sioux Falls radar (KFSD), 134 km from the middle of the area, began a volume at 23:55 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
- 30%
- 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
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 19, 7:56 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Ida, Plymouth, Woodbury | 38 min |
| May 19, 8:28 PM CDT | Severe Thunderstorm Warning | DMX | Crawford | 47 min |
| May 19, 9:00 PM CDT | Severe Thunderstorm Warning | DMX | Audubon, Calhoun, Carroll, Sac | 27 min |
| May 19, 9:09 PM CDT | Severe Thunderstorm Warning | FSD | Cherokee, Ida, Plymouth, Woodbury | 51 min |
| May 19, 9:38 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee, Clay, O'Brien, Plymouth | 37 min |
| May 19, 10:11 PM CDT | Flash Flood Warning | FSD | Clay, Dickinson, O'Brien | 3 hr |
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 12:00Z, 11.9 hours before the alert went out and 138 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
- 438 J/kg
- Mixed-layer CIN
- -453 J/kg
- Mixed-layer LCL
- 1205 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 348 m²/s²
- 0-3 km storm-relative helicity
- 455 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 |
|---|---|---|---|---|
| May 19, 2:36 PM CDT | Mesoscale Discussion | SPC | Fremont, Harrison, Mills, Pottawattamie | 84 min |
| May 19, 3:25 PM CDT | Severe Thunderstorm Watch | SPC | Fremont, Harrison, Mills, Monona, Pottawattamie, Shelby | 7 hr |
| May 19, 5:41 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Cherokee, Clay, Crawford, Harrison, Ida and 10 more | 64 min |
| May 19, 12:51 AM CDT | Mesoscale Discussion | SPC | Brown, Keya Paha | 84 min |
| May 19, 1:37 PM CDT | Mesoscale Discussion | SPC | Chase, Dundy, Hayes, Hitchcock, Red Willow | 113 min |
Nearby
Severe Thunderstorm Watches in Iowa, 2012Severe Thunderstorm Watches in Nebraska, 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.