Alert archive / Iowa / Tornado Watches in 2018
Tornado Watch 399
The Storm Prediction Center issued this tornado watch at Oct 8, 2018, 5:33 PM CDT for 17 counties in Iowa; Atchison County, Doniphan County, Kansas; 16 counties in Missouri. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 8, 2018, 5:33 PM CDT (22:33 UTC)
- Expired
- Oct 8, 2018, 10:00 PM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 35 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, Mahaska County, IA, Marion County, IA, Monroe County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Atchison County, KS, Doniphan County, KS, Andrew County, MO, Buchanan County, MO, Caldwell County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Holt County, MO, Livingston County, MO, Mercer County, MO, Nodaway County, MO, Putnam County, MO, Sullivan County, MO, Worth County, MO
The radar
The Des Moines radar (KDMX), 162 km from the middle of the area, began a volume at 22:37 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
- 30%
- One or more EF2 to EF5 tornadoes
- 10%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 20%
- 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
- 50%
Warnings issued inside it
13 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 8, 6:01 PM CDT | Severe Thunderstorm Warning | EAX | Daviess, Harrison | 29 min |
| Oct 8, 6:06 PM CDT | Severe Thunderstorm Warning | EAX | Putnam | 24 min |
| Oct 8, 6:14 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Wayne | 46 min |
| Oct 8, 6:14 PM CDT | Tornado Warning | EAX | Putnam | 31 min |
| Oct 8, 6:35 PM CDT | Severe Thunderstorm Warning | DMX | Decatur, Ringgold | 40 min |
| Oct 8, 6:36 PM CDT | Tornado Warning | DMX | Appanoose | 24 min |
| Oct 8, 6:45 PM CDT | Severe Thunderstorm Warning | EAX | Harrison, Mercer | 45 min |
| Oct 8, 6:47 PM CDT | Tornado Warning | DMX | Decatur, Ringgold | 43 min |
| Oct 8, 6:50 PM CDT | Tornado Warning | EAX | Harrison, Mercer | 25 min |
| Oct 8, 7:11 PM CDT | Severe Thunderstorm Warning | DMX | Decatur, Wayne | 34 min |
| Oct 8, 7:23 PM CDT | Tornado Warning | DMX | Clarke, Decatur | 37 min |
| Oct 8, 7:59 PM CDT | Tornado Warning | DMX | Clarke, Lucas, Warren | 31 min |
| Oct 8, 9:54 PM CDT | Severe Thunderstorm Warning | DMX | Mahaska, Poweshiek | 21 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 12:00Z, 10.6 hours before the alert went out and 234 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 457 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 97 m²/s²
- 0-3 km storm-relative helicity
- 101 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 |
|---|---|---|---|---|
| Oct 8, 1:49 PM CDT | Mesoscale Discussion | SPC | Atchison, Brown, Chase, Doniphan, Douglas, Geary and 12 more | 116 min |
Nearby
Tornado Watches in Iowa, 2018Tornado Watches in Missouri, 2018Tornado Watches in Kansas, 2018Every tornado watch in 2018
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.