Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 69, NWS Des Moines, IA

October 9, 2018Jasper County, Poweshiek County, Iowa

NWS Des Moines, IA issued this tornado warning at Oct 9, 2018, 4:59 PM CDT for Jasper County, Poweshiek County, Iowa. It was in force for 31 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Oct 9, 2018, 4:59 PM CDT (21:59 UTC)
Expired: Oct 9, 2018, 5:30 PM CDT
In force: 31 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Jasper County, IA, Poweshiek County, IA

The radar

The Des Moines radar (KDMX), 75 km from the middle of the area, began a volume at 22:02 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Oct 9, 1:46 PM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.0 hours before the alert went out and 193 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 459 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 1071 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 82 m²/s²
0-3 km storm-relative helicity: 116 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

As transmitted.

969 
WFUS53 KDMX 092159
TORDMX
IAC099-157-092230-
/O.NEW.KDMX.TO.W.0069.181009T2159Z-181009T2230Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
459 PM CDT TUE OCT 9 2018

The National Weather Service in Des Moines  has issued a

* Tornado Warning for...
  Northwestern Poweshiek County in central Iowa...
  Northeastern Jasper County in central Iowa...

* Until 530 PM CDT.
    
* At 459 PM CDT, a severe thunderstorm capable of producing a 
  tornado was located 6 miles southwest of Grinnell, moving 
  northeast at 30 mph.

  HAZARD...Tornado.

  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...
  Rock Creek Lake around 510 PM CDT.
  Grinnell around 515 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Oakland Acres and Rock Creek State Park.

This includes Interstate 80 between mile markers 175 and 179.
 
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.

&&

LAT...LON 4165 9282 4167 9289 4186 9288 4186 9266
TIME...MOT...LOC 2159Z 203DEG 25KT 4169 9284 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

Martin

3 follow-up statements

324 
WWUS53 KDMX 092208
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
508 PM CDT TUE OCT 9 2018

IAC099-157-092230-
/O.CON.KDMX.TO.W.0069.000000T0000Z-181009T2230Z/
Poweshiek IA-Jasper IA-
508 PM CDT TUE OCT 9 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 530 PM CDT FOR
NORTHWESTERN POWESHIEK AND NORTHEASTERN JASPER COUNTIES...
    
At 507 PM CDT, a severe thunderstorm capable of producing a tornado 
was located over Rock Creek Lake, or 4 miles west of Grinnell, 
moving north at 25 mph.

HAZARD...Tornado.

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.

Locations impacted include...
Grinnell, Rock Creek Lake, Oakland Acres and Rock Creek State Park. 

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.

&&

LAT...LON 4170 9278 4171 9289 4186 9288 4186 9266
TIME...MOT...LOC 2207Z 200DEG 20KT 4172 9283 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

Martin

321 
WWUS53 KDMX 092213
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
513 PM CDT TUE OCT 9 2018

IAC099-157-092230-
/O.CON.KDMX.TO.W.0069.000000T0000Z-181009T2230Z/
Poweshiek IA-Jasper IA-
513 PM CDT TUE OCT 9 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 530 PM CDT FOR
NORTHWESTERN POWESHIEK AND NORTHEASTERN JASPER COUNTIES...
    
At 513 PM CDT, a severe thunderstorm capable of producing a tornado 
was located near Rock Creek Lake, or 4 miles west northwest of 
Grinnell, moving north at 30 mph.

HAZARD...Tornado.

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.

Locations impacted include...
Rock Creek Lake and Rock Creek State Park. 

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.

&&

LAT...LON 4174 9279 4175 9287 4186 9288 4186 9271
TIME...MOT...LOC 2213Z 198DEG 26KT 4177 9282 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

Martin

912 
WWUS53 KDMX 092227 RRA
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
527 PM CDT TUE OCT 9 2018

IAC099-157-092237-
/O.EXP.KDMX.TO.W.0069.000000T0000Z-181009T2230Z/
Poweshiek IA-Jasper IA-
527 PM CDT TUE OCT 9 2018

...THE TORNADO WARNING FOR NORTHWESTERN POWESHIEK AND NORTHEASTERN
JASPER COUNTIES WILL EXPIRE AT 530 PM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

A Tornado Watch remains in effect until 900 PM CDT for central Iowa.

LAT...LON 4174 9279 4175 9287 4186 9288 4186 9271
TIME...MOT...LOC 2227Z 203DEG 25KT 4185 9277 

$$

Martin

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
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 Tornado observed	DMX	Clarke, Lucas, Warren	31 min
Oct 8, 9:54 PM CDT	Severe Thunderstorm Warning	DMX	Mahaska, Poweshiek	21 min
Oct 8, 10:03 PM CDT	Tornado Warning	DMX	Poweshiek	15 min
Oct 8, 10:26 PM CDT	River Flood Warning	DMX	Polk	7 days
Oct 8, 10:26 PM CDT	River Flood Warning	DMX	Polk	7 days
Oct 8, 10:31 PM CDT	River Flood Watch	DMX	Decatur	3 hr
Oct 9, 12:58 AM CDT	River Flood Warning	DMX	Decatur	4 days
Oct 9, 1:48 AM CDT	Areal Flood Warning	DMX	Clarke, Decatur, Jasper, Lucas, Mahaska, Marion and 6 more	24 hr
Oct 9, 2:49 AM CDT	River Flood Warning	DMX	Polk, Story	3 days
Oct 9, 6:39 AM CDT	River Flood Warning	DMX	Marshall	7 days
Oct 9, 6:39 AM CDT	River Flood Warning	DMX	Black Hawk	6 days
Oct 9, 6:39 AM CDT	River Flood Warning	DMX	Dallas, Greene	5 days
Oct 9, 10:20 AM CDT	River Flood Warning	DMX	Black Hawk, Bremer, Butler	35 hr
Oct 9, 10:20 AM CDT	River Flood Warning	DMX	Lucas, Wayne	64 hr
Oct 9, 11:33 AM CDT	River Flood Warning	DMX	Dallas, Polk	6 days
Oct 9, 12:38 PM CDT	River Flood Watch	DMX	Davis, Wapello	10 hr
Oct 9, 2:16 PM CDT	Tornado Warning	DMX	Mahaska, Marion, Monroe	29 min
Oct 9, 3:22 PM CDT	River Flood Warning	DMX	Story	7 hr
Oct 9, 3:22 PM CDT	River Flood Warning	DMX	Story	20 hr
Oct 9, 3:32 PM CDT	Tornado Warning	DMX	Appanoose, Monroe	43 min
Oct 9, 3:42 PM CDT	Tornado Warning	DMX	Mahaska, Marion, Monroe	22 min
Oct 9, 4:21 PM CDT	Tornado Warning Tornado observed	DMX	Poweshiek, Tama	24 min
Oct 9, 4:28 PM CDT	Tornado Warning	DMX	Ringgold, Taylor	47 min
Oct 9, 4:47 PM CDT	River Flood Watch	DMX	Jasper, Marion, Polk	29 hr
Oct 9, 4:58 PM CDT	Tornado Warning Tornado observed	DMX	Tama	32 min
Oct 9, 5:13 PM CDT	Tornado Warning	DMX	Adair, Adams, Union	32 min
Oct 9, 5:44 PM CDT	Tornado Warning Tornado observed	DMX	Adair	46 min
Oct 9, 6:11 PM CDT	Tornado Warning Tornado observed	DMX	Adair, Dallas, Guthrie	49 min
Oct 9, 6:30 PM CDT	Tornado Warning	DMX	Polk, Warren	30 min

Nearby

Tornado Warnings in Iowa, 2018 Every tornado warning in 2018 Tornadoes 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.