Alert archive / Iowa / Tornado Warnings in 2018

Tornado Warning 20, NWS Quad Cities, IA

August 20, 2018Clinton County, Jackson County, Iowa

NWS Quad Cities, IA issued this tornado warning at Aug 20, 2018, 3:50 PM CDT for Clinton County, Jackson County, Iowa. It was in force for 40 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: Aug 20, 2018, 3:50 PM CDT (20:50 UTC)
Expired: Aug 20, 2018, 4:30 PM CDT
In force: 40 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Tornado: Observed
Hail: 0.75 in

Counties Clinton County, IA, Jackson County, IA

The radar

The Quad Cities radar (KDVN), 50 km from the middle of the area, began a volume at 20:51 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 nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 8.8 hours before the alert went out and 49 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: 224 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 765 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 94 m²/s²
0-3 km storm-relative helicity: 73 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

294 
WFUS53 KDVN 202050
TORDVN
IAC045-097-202130-
/O.NEW.KDVN.TO.W.0020.180820T2050Z-180820T2130Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Quad Cities IA/IL
350 PM CDT MON AUG 20 2018

The National Weather Service in the Quad Cities has issued a

* Tornado Warning for...
  South central Jackson County in east central Iowa...
  North central Clinton County in east central Iowa...

* Until 430 PM CDT.

* At 349 PM CDT, a confirmed tornado was located over Delmar, or near
  Maquoketa, moving north at 15 mph.

  HAZARD...Damaging tornado.

  SOURCE...Weather spotters confirmed tornado.

  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.

* The tornado will be near...
  Maquoketa and Spragueville around 410 PM CDT.
  Andrew and Springbrook around 430 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Jackson County Fairgrounds.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. 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 4197 9046 4197 9063 4219 9069 4219 9037
TIME...MOT...LOC 2049Z 182DEG 11KT 4201 9056 

TORNADO...OBSERVED
HAIL...<.75IN

$$

Gibbs

5 follow-up statements

045 
WWUS53 KDVN 202053
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
353 PM CDT MON AUG 20 2018

IAC045-097-202130-
/O.CON.KDVN.TO.W.0020.000000T0000Z-180820T2130Z/
Jackson IA-Clinton IA-
353 PM CDT MON AUG 20 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 430 PM CDT FOR SOUTH
CENTRAL JACKSON AND NORTH CENTRAL CLINTON COUNTIES...
    
At 353 PM CDT, a confirmed tornado was located near Delmar, or near
Maquoketa, moving north at 15 mph.

HAZARD...Damaging tornado.

SOURCE...Weather spotters confirmed tornado.

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 tornado will be near...
  Maquoketa and Spragueville around 405 PM CDT.
  Andrew and Springbrook around 430 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Jackson County Fairgrounds.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. 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.

If a tornado or other severe weather is spotted, report it to the
National Weather Service or your local nearest law enforcement agency
who will send your report. This act may save lives of others in the
path of dangerous weather.

&&

LAT...LON 4197 9046 4197 9063 4219 9069 4219 9037
TIME...MOT...LOC 2053Z 180DEG 12KT 4203 9056 

TORNADO...OBSERVED
HAIL...<.75IN

$$

Gibbs

916 
WWUS53 KDVN 202104
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
404 PM CDT MON AUG 20 2018

IAC045-202114-
/O.CAN.KDVN.TO.W.0020.000000T0000Z-180820T2130Z/
Clinton IA-
404 PM CDT MON AUG 20 2018

...THE TORNADO WARNING FOR NORTH CENTRAL CLINTON COUNTY IS
CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area.  Therefore, the warning has been cancelled.

LAT...LON 4219 9037 4203 9043 4203 9065 4219 9069
TIME...MOT...LOC 2104Z 182DEG 11KT 4206 9056 

$$

IAC097-202130-
/O.CON.KDVN.TO.W.0020.000000T0000Z-180820T2130Z/
Jackson IA-
404 PM CDT MON AUG 20 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 430 PM CDT FOR SOUTH
CENTRAL JACKSON COUNTY...
    
At 404 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Delmar, or near Maquoketa, moving north at 15 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...
  Andrew and Springbrook around 430 PM CDT.

Other locations impacted by this tornadic thunderstorm include
Jackson County Fairgrounds.

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.

If a tornado or other severe weather is spotted, report it to the
National Weather Service or your local nearest law enforcement agency
who will send your report. This act may save lives of others in the
path of dangerous weather.

&&

LAT...LON 4219 9037 4203 9043 4203 9065 4219 9069
TIME...MOT...LOC 2104Z 182DEG 11KT 4206 9056 

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

$$

Gibbs

229 
WWUS53 KDVN 202113
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
413 PM CDT MON AUG 20 2018

IAC097-202130-
/O.CON.KDVN.TO.W.0020.000000T0000Z-180820T2130Z/
Jackson IA-
413 PM CDT MON AUG 20 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 430 PM CDT FOR SOUTH
CENTRAL JACKSON COUNTY...
    
At 412 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Andrew, or near Maquoketa, moving north at 15 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...
  Andrew and Springbrook around 430 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!

This storm has a history of producing tornadoes.  Seek shelter now!
 
If a tornado or other severe weather is spotted, report it to the 
National Weather Service or your local nearest law enforcement 
agency who will send your report. This act may save lives of others 
in the path of dangerous weather.

&&

LAT...LON 4219 9038 4206 9047 4204 9053 4206 9059
      4219 9064
TIME...MOT...LOC 2112Z 187DEG 11KT 4209 9054 

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

$$

Gibbs

898 
WWUS53 KDVN 202121
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
421 PM CDT MON AUG 20 2018

IAC097-202130-
/O.CON.KDVN.TO.W.0020.000000T0000Z-180820T2130Z/
Jackson IA-
421 PM CDT MON AUG 20 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 430 PM CDT FOR SOUTH
CENTRAL JACKSON COUNTY...
    
At 421 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Andrew, or 7 miles northeast of Maquoketa, moving
north at 15 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...
  Andrew and Springbrook around 430 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!

If a tornado or other severe weather is spotted, report it to the
National Weather Service or your local nearest law enforcement agency
who will send your report. This act may save lives of others in the
path of dangerous weather.

&&

LAT...LON 4219 9038 4206 9047 4207 9053 4209 9059
      4219 9064
TIME...MOT...LOC 2121Z 187DEG 11KT 4212 9053 

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

$$

Gibbs

694 
WWUS53 KDVN 202126
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
426 PM CDT MON AUG 20 2018

IAC097-202136-
/O.EXP.KDVN.TO.W.0020.000000T0000Z-180820T2130Z/
Jackson IA-
426 PM CDT MON AUG 20 2018

...THE TORNADO WARNING FOR SOUTH CENTRAL JACKSON COUNTY WILL EXPIRE
AT 430 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
the Quad Cities.

LAT...LON 4219 9038 4206 9047 4207 9053 4209 9059
      4219 9064
TIME...MOT...LOC 2126Z 182DEG 11KT 4213 9053 

$$

Gibbs

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 5:27 PM CDT	Special Weather Statement	DVN	Jones	93 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.