Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 21, NWS Quad Cities, IA

August 28, 2018Iowa County, Iowa

NWS Quad Cities, IA issued this tornado warning at Aug 28, 2018, 5:40 PM CDT for Iowa County, Iowa. It was in force for 35 min. 4 reports 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 28, 2018, 5:40 PM CDT (22:40 UTC)
Expired: Aug 28, 2018, 6:15 PM CDT
In force: 35 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Iowa County, IA

The radar

The Quad Cities radar (KDVN), 118 km from the middle of the area, began a volume at 22:39 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 28, 5:49 PM CDT	TSTM WND DMG	2 Nne North English, IA	POWER LINES DOWN IN HWY 149 & 310TH STREET, VIA KWWL.
Aug 28, 5:52 PM CDT	TSTM WND GST 60	1 Ene Parnell, IA
Aug 28, 5:52 PM CDT	HAIL 0.88	1 Ene Parnell, IA
Aug 28, 5:58 PM CDT	TSTM WND DMG	Parnell, IA	NUMEROUS TREES DOWN ALL OVER TOWN. NO POWER AT RESIDENCE.

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 28, 5:06 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.7 hours before the alert went out and 125 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: 955 J/kg
Mixed-layer CIN: -230 J/kg
Mixed-layer LCL: 1046 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 360 m²/s²
0-3 km storm-relative helicity: 487 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted.

759 
WFUS53 KDVN 282240
TORDVN
IAC095-282315-
/O.NEW.KDVN.TO.W.0021.180828T2240Z-180828T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Quad Cities IA/IL
540 PM CDT TUE AUG 28 2018

The National Weather Service in the Quad Cities has issued a

* Tornado Warning for...
  Southern Iowa County in east central Iowa...

* Until 615 PM CDT.
    
* At 540 PM CDT, a severe thunderstorm capable of producing a tornado
  was located over Millersburg, or 14 miles north of Sigourney,
  moving northeast at 35 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...
  North English around 550 PM CDT.
  Parnell around 555 PM CDT.
  Williamsburg around 600 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Holbrook.

This includes Interstate 80 in Iowa between mile markers 219 and 225.
 
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 4175 9193 4158 9183 4155 9183 4151 9207
      4151 9220 4157 9223
TIME...MOT...LOC 2240Z 243DEG 30KT 4153 9217 

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

$$

McClure

3 follow-up statements

412 
WWUS53 KDVN 282247
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
547 PM CDT TUE AUG 28 2018

IAC095-282315-
/O.CON.KDVN.TO.W.0021.000000T0000Z-180828T2315Z/
Iowa IA-
547 PM CDT TUE AUG 28 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR SOUTHERN
IOWA COUNTY...
    
At 547 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Millersburg, or 14 miles south of Marengo, moving
northeast at 35 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...
  Parnell around 555 PM CDT.
  Williamsburg around 600 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Holbrook.

This includes Interstate 80 in Iowa between mile markers 219 and 225.
 
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 4175 9193 4158 9183 4155 9183 4151 9207
      4151 9220 4157 9223
TIME...MOT...LOC 2247Z 235DEG 31KT 4158 9210 

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

$$

McClure

091 
WWUS53 KDVN 282250
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
550 PM CDT TUE AUG 28 2018

IAC095-282315-
/O.CON.KDVN.TO.W.0021.000000T0000Z-180828T2315Z/
Iowa IA-
550 PM CDT TUE AUG 28 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR
SOUTHEASTERN IOWA COUNTY...
    
At 550 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Parnell, or 14 miles south of Marengo, moving
northeast at 40 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...
  Parnell around 555 PM CDT.
  Williamsburg around 600 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Holbrook.

This includes Interstate 80 in Iowa between mile markers 220 and 225.
 
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 4175 9193 4158 9183 4155 9183 4151 9207
      4159 9217
TIME...MOT...LOC 2250Z 237DEG 33KT 4158 9208 

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

$$

McClure

016 
WWUS53 KDVN 282306 RRA
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
606 PM CDT TUE AUG 28 2018

IAC095-282316-
/O.EXP.KDVN.TO.W.0021.000000T0000Z-180828T2315Z/
Iowa IA-
606 PM CDT TUE AUG 28 2018

...THE TORNADO WARNING FOR SOUTHEASTERN IOWA COUNTY WILL EXPIRE AT
615 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
southeastern and east central Iowa.

LAT...LON 4175 9193 4158 9183 4155 9183 4151 9207
      4159 9217
TIME...MOT...LOC 2306Z 243DEG 30KT 4164 9193 

$$

McClure

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 28, 9:08 AM CDT	Flash Flood Watch	DVN	Benton, Buchanan, Cedar, Clinton, Delaware, Des Moines and 15 more	20 hr
Aug 28, 2:16 PM CDT	Special Weather Statement	DVN	Scott	59 min
Aug 28, 5:14 PM CDT	Severe Thunderstorm Warning	DVN	Iowa, Johnson, Keokuk, Washington	61 min
Aug 28, 5:22 PM CDT	Special Weather Statement	DVN	Benton	53 min
Aug 28, 5:51 PM CDT	Severe Thunderstorm Warning	DVN	Henry, Jefferson, Keokuk, Van Buren, Washington	39 min
Aug 28, 5:59 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Johnson, Louisa, Muscatine, Washington	61 min
Aug 28, 6:02 PM CDT	Tornado Warning	DVN	Iowa, Johnson	28 min
Aug 28, 6:18 PM CDT	Severe Thunderstorm Warning	DVN	Henry, Louisa, Washington	42 min
Aug 28, 6:24 PM CDT	Special Weather Statement	DVN	Jones, Linn	36 min
Aug 28, 6:37 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Clinton, Jackson, Johnson, Jones, Linn	38 min
Aug 28, 6:41 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Clinton, Muscatine, Scott	64 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.