Tornado warning issued for Johnson County through 6:30 p.m.

Update 6:31 p.m.:

NWS letting Tornado Warning expire for Johnson CountyJuly 11, 2017

NWS letting Tornado Warning expire for Johnson County

— Rebecca Kopelman (@KopelmanWX)

Update 6:26 p.m.:In another update, the National Weather Service in the Quad Cities notes that a tornado that had been on the ground has receded back into the sky, but they are watching the rotations to see if it will produce more tornadic activity. They still stress caution in areas of rural northwestern Johnson County.

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 630 PM CDT FOR NORTHWESTERN JOHNSON COUNTY... At 622 PM CDT, a severe thunderstorm capable of producing a tornado was located near Swisher, or 12 miles south of Cedar Rapids, moving east at 15 mph. The tornado has lifted but a circulation remains capable of producing a tornado. 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 tornadic thunderstorm will remain over mainly rural areas of northwestern Johnson County, including the following locations: Twin View Heights, Sandy Beach Camp Ground, F.W. Kent Park, Sugar Bottom Camp Ground and Cou Falls.

Update 6:19 p.m.:

The warning from the National Weather Service has been amended to affect mostly a tight band in Northern Johnson County.

A TORNADO WARNING REMAINS IN EFFECT UNTIL 630 PM CDT FOR NORTHWESTERN JOHNSON COUNTY... At 609 PM CDT, a confirmed tornado was located near Amana, or 12 miles east of Marengo, moving northeast at 20 mph. HAZARD...Damaging tornado. SOURCE...Law enforcement 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... Coralville, North Liberty, Tiffin, Swisher, Shueyville and Lake Macbride State Park around 630 PM CDT. Other locations impacted by this tornadic thunderstorm include Twin View Heights, Sandy Beach Camp Ground, F.W. Kent Park, Sugar Bottom Camp Ground and Cou Falls.

Update: 6:12 p.m.:

This July 11, 2017

This #tornado was spotted near Williamsburg, #Iowa. Video: Jennifer Sparlin #IAwx pic.twitter.com/2e1xyxJrSb

— Zach Sharpe (@StormChaserZach)

The National Weather Service in the Quad Cities has issued a tornado warning for Northern Johnson County after a tornado was spotted moving east at 5:55 p.m. southeast of Marengo.

From the NWS:

At 556 PM CDT, a confirmed tornado was located 3 miles northeast of near Conroy, or 7 miles southeast of Marengo, and is moving northeast at 15 MPH. HAZARD...Damaging tornado. SOURCE...Law enforcement 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... Amana around 610 PM CDT. Oxford around 620 PM CDT. Coralville, North Liberty, Tiffin, Swisher and Shueyville around 630 PM CDT. Other locations impacted by this tornadic thunderstorm include Middle Amana, Iowa City Municipal Airport, South Amana, Homestead, West Amana, Sugar Bottom Camp Ground, Cou Falls, Johnson County Fairgrounds, Upper South Amana and Cosgrove. This includes the following highways... Interstate 80 in Iowa between mile markers 219 and 245. Interstate 380 between mile markers 1 and 11. 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.