A severe thunderstorm warning has been extended until 7:15 p.m. The intial warning was issued for Washington, Keokuk, Johnson, Iowa, Benton and Linn counties until 6:30 p.m.
The National Weather Service has advised:

AT 537 PM CDT…SEVERE THUNDERSTORMS WERE LOCATED ALONG A LINE
EXTENDING FROM 9 MILES NORTHWEST OF DYSART TO MARTINSBURG…AND
MOVING EAST AT 35 MPH. WIDESPREAD 40 TO 50 MPH WINDS CAN BE EXPECTED
WITH ISOLATED 60 MPH WINDS.

HAZARD…60 MPH WIND GUSTS AND PENNY SIZE HAIL.

SOURCE…RADAR INDICATED.

IMPACT…EXPECT DAMAGE TO ROOFS…SIDING AND TREES.

LOCATIONS IMPACTED INCLUDE…
SIGOURNEY…MARENGO…VINTON…WASHINGTON…CEDAR RAPIDS…IOWA
CITY…MILLERSBURG…NORTH ENGLISH…VAN HORNE…PARNELL AND
WILLIAMSBURG.

THIS INCLUDES INTERSTATE 80 IN IOWA BETWEEN MILE MARKERS 205 AND 253.

THIS INCLUDES INTERSTATE 380 BETWEEN MILE MARKERS 1 AND 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS…

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

TORRENTIAL RAINFALL IS OCCURRING WITH THESE STORMS…AND MAY LEAD TO
FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS!