Alert archive / Iowa / Tornado Warnings in 2017
Tornado Warning 32, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this tornado warning at Aug 18, 2017, 8:06 PM CDT for Clay County, O'Brien County, Osceola County, Iowa. It was in force for 24 min. 1 report came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 18, 2017, 8:06 PM CDT (01:06 UTC)
- Expired
- Aug 18, 2017, 8:30 PM CDT
- In force
- 24 min
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 2.0 in
Counties Clay County, IA, O'Brien County, IA, Osceola County, IA
The radar
The Sioux Falls radar (KFSD), 106 km from the middle of the area, began a volume at 01:07 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 was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 18, 8:07 PM CDT | TORNADO | 5 Nw Melvin, IA | EF2 TORNADO TRAVELED 6 MILES WITH A 250 YARD WIDE PATH. THE TORNADO LIFTED AT 8:27 ABOUT A 1/2 MILE SOUTHWEST OF MELVIN. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 18, 4:51 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 1.1 hours before the alert went out and 228 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
- 1353 J/kg
- Mixed-layer CIN
- -118 J/kg
- Mixed-layer LCL
- 1673 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 30 m²/s²
- 0-3 km storm-relative helicity
- 61 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.1
The text
As transmitted.
367
WFUS53 KFSD 190106
TORFSD
IAC041-141-143-190130-
/O.NEW.KFSD.TO.W.0032.170819T0106Z-170819T0130Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Sioux Falls SD
806 PM CDT FRI AUG 18 2017
The National Weather Service in Sioux Falls has issued a
* Tornado Warning for...
Central Osceola County in northwestern Iowa...
Northwestern Clay County in northwestern Iowa...
Northeastern O'Brien County in northwestern Iowa...
* Until 830 PM CDT
* At 806 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Sibley, moving southeast at 40 mph.
HAZARD...Tornado and hail up to two inches in diameter.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* This dangerous storm will be near...
Ocheyedan around 810 PM CDT.
Melvin around 820 PM CDT.
Hartley around 830 PM CDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!
&&
LAT...LON 4309 9558 4345 9575 4350 9557 4328 9539
4326 9539 4326 9536 4318 9530
TIME...MOT...LOC 0106Z 327DEG 34KT 4340 9565
TORNADO...RADAR INDICATED
HAIL...2.00IN
$$
Ferguson2 follow-up statements
072
WWUS53 KFSD 190110
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
810 PM CDT FRI AUG 18 2017
IAC041-141-143-190130-
/O.CON.KFSD.TO.W.0032.000000T0000Z-170819T0130Z/
Osceola IA-Clay IA-O'Brien IA-
810 PM CDT FRI AUG 18 2017
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 830 PM CDT FOR CENTRAL
OSCEOLA...NORTHWESTERN CLAY AND NORTHEASTERN O'BRIEN COUNTIES...
At 810 PM CDT, a severe thunderstorm capable of producing a tornado
was located between Sibley and Melvin, moving southeast at 45 mph.
HAZARD...Tornado and two inch hail.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
This dangerous storm will be near...
Melvin around 815 PM CDT.
Hartley around 830 PM CDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!
&&
LAT...LON 4309 9558 4345 9575 4350 9557 4328 9539
4326 9539 4326 9536 4318 9530
TIME...MOT...LOC 0110Z 331DEG 38KT 4334 9565
TORNADO...RADAR INDICATED
HAIL...2.00IN
$$
Ferguson349
WWUS53 KFSD 190116
SVSFSD
Severe Weather Statement
National Weather Service Sioux Falls SD
816 PM CDT FRI AUG 18 2017
IAC041-141-143-190130-
/O.CON.KFSD.TO.W.0032.000000T0000Z-170819T0130Z/
Osceola IA-Clay IA-O'Brien IA-
816 PM CDT FRI AUG 18 2017
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 830 PM CDT FOR CENTRAL
OSCEOLA...NORTHWESTERN CLAY AND NORTHEASTERN O'BRIEN COUNTIES...
At 816 PM CDT, a confirmed large and extremely dangerous tornado was
located over Melvin, or 7 miles southeast of Sibley, moving southeast
at 30 mph.
This is a PARTICULARLY DANGEROUS SITUATION. TAKE COVER NOW!
HAZARD...Damaging tornado.
SOURCE...Radar confirmed tornado.
IMPACT...You are in a life-threatening situation. Flying debris may
be deadly to those caught without shelter. Mobile homes
will be destroyed. Considerable damage to homes,
businesses, and vehicles is likely and complete destruction
is possible.
The tornado will be near...
Melvin around 825 PM CDT.
Hartley around 830 PM CDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
To repeat, a large, extremely dangerous and potentially deadly
tornado is on the ground. To protect your life, TAKE COVER NOW! Move
to a basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.
Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!
&&
LAT...LON 4309 9558 4345 9575 4350 9557 4328 9539
4326 9539 4326 9536 4318 9530
TIME...MOT...LOC 0116Z 331DEG 25KT 4332 9564
TORNADO...OBSERVED
TORNADO DAMAGE THREAT...CONSIDERABLE
HAIL...2.00IN
$$
FergusonThe office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 7:45 PM CDT | Severe Thunderstorm Warning | FSD | Osceola | 30 min |
| Aug 18, 7:49 PM CDT | Tornado Warning | FSD | Osceola | 26 min |
| Aug 18, 8:25 PM CDT | Tornado Warning | FSD | Clay, O'Brien, Osceola | 35 min |
| Aug 18, 8:37 PM CDT | Tornado Warning | FSD | Clay, O'Brien | 23 min |
| Aug 18, 8:54 PM CDT | Tornado Warning | FSD | Buena Vista, Cherokee, Clay, O'Brien | 36 min |
| Aug 18, 9:26 PM CDT | Tornado Warning | FSD | Buena Vista, Cherokee, O'Brien | 34 min |
| Aug 18, 9:53 PM CDT | Severe Thunderstorm Warning | FSD | Buena Vista, Cherokee, Ida | 37 min |
Nearby
Tornado Warnings in Iowa, 2017Every tornado warning in 2017Tornadoes in 2017
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.