Alert archive / Iowa / Tornado Warnings in 2017

Tornado Warning 48, NWS Quad Cities, IA

July 21, 2017Johnson County, Iowa

NWS Quad Cities, IA issued this tornado warning at Jul 21, 2017, 4:49 PM CDT for Johnson County, Iowa. It was in force for 56 min. 6 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: Jul 21, 2017, 4:49 PM CDT (21:49 UTC)
Expired: Jul 21, 2017, 5:45 PM CDT
In force: 56 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.75 in

County Johnson County, IA

The radar

The Quad Cities radar (KDVN), 79 km from the middle of the area, began a volume at 21:53 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
Jul 21, 5:09 PM CDT	TSTM WND DMG	Wnw Williamstown, IA	TREE BRANCHES DOWN. WIND ESTIMATED AT 50-60 MPH.
Jul 21, 5:12 PM CDT	HAIL 1	Wnw Williamstown, IA
Jul 21, 5:19 PM CDT	TSTM WND GST 53	Iowa City Municipal Air, IA
Jul 21, 5:22 PM CDT	HAIL 1	4 Sw Coralville, IA	REPORT VIA KCRG FACEBOOK.
Jul 21, 5:29 PM CDT	HAIL 0.88	2 W Iowa City, IA
Jul 21, 5:44 PM CDT	TORNADO	6 Ne Kalona, IA	REPORT DELAYED - POSSIBLE TORNADO MOVING NORTHEAST - FUNNEL CLOUD APPEARED TO BRIEFLY TOUCH DOWN THEN LIFTED BACK INTO THE STORM

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.8 hours before the alert went out and 86 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: 81 J/kg
Mixed-layer CIN: -302 J/kg
Mixed-layer LCL: 1173 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 125 m²/s²
0-3 km storm-relative helicity: 192 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

403 
WFUS53 KDVN 212149
TORDVN
IAC103-212245-
/O.NEW.KDVN.TO.W.0048.170721T2149Z-170721T2245Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Quad Cities IA/IL
449 PM CDT FRI JUL 21 2017

The National Weather Service in the Quad Cities has issued a

* Tornado Warning for...
  Central Johnson County in east central Iowa...

* Until 545 PM CDT
    
* At 448 PM CDT, a severe thunderstorm capable of producing a tornado
  was located 7 miles northwest of Kalona, or 13 miles west of Iowa
  City, moving east at 20 mph.

  HAZARD...Tornado and golf ball size 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...
  University Heights around 520 PM CDT. 
  Hills around 525 PM CDT. 
  Iowa City around 530 PM CDT. 
  Lone Tree around 540 PM CDT. 
  West Branch around 545 PM CDT. 

Other locations impacted by this tornadic thunderstorm include Iowa
City Municipal Airport, Frytown, Windham, Johnson County Fairgrounds,
University Of Iowa, Hills Access, Cosgrove, Sharon Center and Amish.

This includes Interstate 80 in Iowa between mile markers 247 and 253.
 
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.

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

&&

LAT...LON 4170 9137 4157 9136 4148 9138 4150 9148
      4150 9152 4151 9153 4151 9162 4154 9183
      4165 9183
TIME...MOT...LOC 2148Z 266DEG 18KT 4158 9178 

TORNADO...RADAR INDICATED
HAIL...1.75IN

$$

Gibbs

4 follow-up statements

231 
WWUS53 KDVN 212159
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
459 PM CDT FRI JUL 21 2017

IAC103-212245-
/O.CON.KDVN.TO.W.0048.000000T0000Z-170721T2245Z/
Johnson IA-
459 PM CDT FRI JUL 21 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 545 PM CDT FOR CENTRAL
JOHNSON COUNTY...
    
At 459 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Kalona, or 11 miles southwest of Iowa City, moving
east at 15 mph.

HAZARD...Tornado and golf ball size 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...
  University Heights around 530 PM CDT. 
  Hills around 535 PM CDT. 
  Iowa City and Lone Tree around 545 PM CDT. 

Other locations impacted by this tornadic thunderstorm include Iowa
City Municipal Airport, Frytown, Windham, Johnson County Fairgrounds,
University Of Iowa, Hills Access, Cosgrove, Sharon Center and Amish.

This includes Interstate 80 in Iowa between mile markers 247 and 253.
 
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 4170 9137 4157 9136 4148 9138 4150 9148
      4150 9152 4151 9153 4151 9162 4154 9183
      4165 9183
TIME...MOT...LOC 2159Z 265DEG 15KT 4158 9174 

TORNADO...RADAR INDICATED
HAIL...1.75IN

$$

Gibbs

048 
WWUS53 KDVN 212207
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
507 PM CDT FRI JUL 21 2017

IAC103-212245-
/O.CON.KDVN.TO.W.0048.000000T0000Z-170721T2245Z/
Johnson IA-
507 PM CDT FRI JUL 21 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 545 PM CDT FOR CENTRAL
JOHNSON COUNTY...
    
At 507 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Kalona, or 9 miles southwest of Iowa City, moving
east at 15 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...
  University Heights around 530 PM CDT. 
  Hills around 535 PM CDT. 
  Iowa City and Lone Tree around 545 PM CDT. 

Other locations impacted by this tornadic thunderstorm include Iowa
City Municipal Airport, Frytown, Windham, Johnson County Fairgrounds,
University Of Iowa, Hills Access, Cosgrove, Sharon Center and Amish.

This includes Interstate 80 in Iowa between mile markers 247 and 253.
 
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 4170 9137 4157 9136 4148 9138 4150 9148
      4150 9152 4151 9153 4151 9162 4154 9183
      4165 9183
TIME...MOT...LOC 2207Z 266DEG 15KT 4158 9169 

TORNADO...RADAR INDICATED
HAIL...2.00IN

$$

Gibbs

154 
WWUS53 KDVN 212216
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
516 PM CDT FRI JUL 21 2017

IAC103-212245-
/O.CON.KDVN.TO.W.0048.000000T0000Z-170721T2245Z/
Johnson IA-
516 PM CDT FRI JUL 21 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 545 PM CDT FOR CENTRAL
JOHNSON COUNTY...
    
At 516 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Hills, or 7 miles south of Iowa City, moving east at
25 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...
  Hills around 520 PM CDT. 
  Lone Tree around 535 PM CDT. 

Other locations impacted by this tornadic thunderstorm include Iowa
City Municipal Airport, Frytown, Windham, Johnson County Fairgrounds,
University Of Iowa, Hills Access, Cosgrove, Sharon Center and Amish.

This includes Interstate 80 in Iowa between mile markers 247 and 253.
 
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 4170 9137 4157 9136 4148 9138 4150 9148
      4150 9152 4151 9153 4151 9162 4154 9183
      4165 9183
TIME...MOT...LOC 2216Z 274DEG 22KT 4156 9158 

TORNADO...RADAR INDICATED
HAIL...2.00IN

$$

Gibbs

038 
WWUS53 KDVN 212229
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
529 PM CDT FRI JUL 21 2017

IAC103-212245-
/O.CON.KDVN.TO.W.0048.000000T0000Z-170721T2245Z/
Johnson IA-
529 PM CDT FRI JUL 21 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 545 PM CDT FOR
SOUTHEASTERN JOHNSON COUNTY...
    
At 529 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Hills, or near Iowa City, moving east at 20 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...
  Lone Tree around 545 PM CDT. 

Other locations impacted by this tornadic thunderstorm include
University Of Iowa, Iowa City Municipal Airport, Hills Access, Sharon
Center and Johnson County Fairgrounds.

This includes Interstate 80 in Iowa between mile markers 247 and 253.
 
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 4170 9137 4157 9136 4148 9138 4150 9148
      4150 9152 4151 9153 4152 9168 4152 9171
      4166 9171
TIME...MOT...LOC 2229Z 272DEG 18KT 4156 9152 

TORNADO...RADAR INDICATED
HAIL...2.00IN

$$

Gibbs

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 7:05 PM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Henry	40 min
Jul 20, 7:37 PM CDT	Severe Thunderstorm Warning	DVN	Henry, Jefferson	53 min
Jul 20, 7:56 PM CDT	Flash Flood Warning	DVN	Henry, Jefferson	6 hr
Jul 20, 8:27 PM CDT	Severe Thunderstorm Warning	DVN	Henry, Jefferson	46 min
Jul 20, 8:45 PM CDT	Severe Thunderstorm Warning	DVN	Louisa, Muscatine	31 min
Jul 20, 8:58 PM CDT	Flash Flood Warning	DVN	Henry, Jefferson, Louisa, Muscatine, Washington	6 hr
Jul 20, 9:44 PM CDT	Severe Thunderstorm Warning	DVN	Muscatine, Scott	46 min
Jul 20, 9:46 PM CDT	Severe Thunderstorm Warning	DVN	Jefferson, Keokuk, Washington	30 min
Jul 20, 10:13 PM CDT	Severe Thunderstorm Warning	DVN	Clinton, Scott	45 min
Jul 20, 10:39 PM CDT	Severe Thunderstorm Warning	DVN	Clinton, Scott	35 min
Jul 20, 11:39 PM CDT	Severe Thunderstorm Warning	DVN	Benton, Iowa, Keokuk	27 min
Jul 21, 12:40 AM CDT	Special Weather Statement	DVN	Cedar, Johnson, Muscatine	65 min
Jul 21, 1:27 AM CDT	Special Weather Statement	DVN	Scott	63 min
Jul 21, 5:10 AM CDT	Special Weather Statement	DVN	Buchanan, Cedar, Jones, Linn	65 min
Jul 21, 2:56 PM CDT	River Flood Watch	DVN	Delaware, Jones	67 hr
Jul 21, 2:56 PM CDT	River Flood Watch	DVN	Jackson	4 days
Jul 21, 2:56 PM CDT	River Flood Watch	DVN	Buchanan, Linn	5 days
Jul 21, 3:51 PM CDT	Severe Thunderstorm Warning	DVN	Iowa, Johnson, Washington	54 min
Jul 21, 4:39 PM CDT	Severe Thunderstorm Warning	DVN	Iowa, Johnson	66 min
Jul 21, 5:01 PM CDT	Severe Thunderstorm Warning	DVN	Cedar, Jones, Linn	59 min
Jul 21, 5:16 PM CDT	Flash Flood Warning	DVN	Cedar, Johnson, Jones, Linn	6 hr
Jul 21, 5:24 PM CDT	Severe Thunderstorm Warning	DVN	Dubuque	37 min
Jul 21, 5:39 PM CDT	Tornado Warning	DVN	Cedar, Johnson, Muscatine	51 min
Jul 21, 6:10 PM CDT	Tornado Warning	DVN	Muscatine	50 min
Jul 21, 6:50 PM CDT	Special Weather Statement	DVN	Clinton, Scott	55 min

Nearby

Tornado Warnings in Iowa, 2017 Every tornado warning in 2017 Tornadoes 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.