Headed For (the) Hills

First storm spotting opportunity of 2018. In the morning hours of Wednesday, May 2, 2018, the Storm Prediction Center (SPC) issued its Day One Convective Outlook that that included a severe weather Moderate Risk for the extreme SW part of the state of Iowa and a Slight Risk for most of the eastern (above left). At 3:55 pm CDT, Severe Thunderstorm Watch 63 was issued for the southeastern part of Iowa and all of the northern part of neighboring Illinois (above right). At this point, I began monitoring radar from my home in Cedar Rapids for a possible spotting move.

At around 5:35 pm, a small storm cell began popping up just south of New Sharon, Iowa, in Mahaska County, moving ENE. Twenty minutes later its radar signature was that of the lower left portion of the radar screen capture shown above. At 6:35 pm these line of storms went severe-warned and at 6:50 pm tornado-warned. It was time to head south. But would I get there in time? The nearest intense cell was less than 20 miles west of US Highway 218 in southern Johnson County.

Arrive ahead of it I did. I chose the Hills, Iowa exit and then the parking area of the town's Casey's General Store, with a open view of the west--in perfect position. This image looks west at 7:46 pm and the approaching storm cell already had a tornadic appearance and motion.

7:50 pm. Looking southwest at the southern part of the storm, showing its shelf cloud appearance in that area. From the camera's perspective, the storm was moving from the background to the right of the image. Its forward speed was 20 mph. Temperature was 70 degrees F, dew point 66 degrees, humidity 88%.

Panorama looking west at 7:51 pm. The forming lowering that would pass in front of me in mere minutes is more pronounced now. This is the last sequence of shots I would take outside my vehicle, as CG lightning was becoming more frequent and I no longer had the desire to tempt fate!

7:53 pm. Now a wall cloud in the northwest sky. Taken from my open driver's side window. The adrenaline was beginning to kick in now!

7:53 pm. At this point I was alternating still shots with video from my Nikon D7200 DSLR camera. This image is a video frame capture. Sirens were now wailing in Hills. The ever-tightening tornadic lowering was now about two miles to my northwest, with a hail core about a half-mile farther.

7:55 pm. Video frame capture. Looking very threatening and approaching Oakcrest Hill Road SE (foreground). The lowering passed about two miles to my north. Inflow winds now picked up as did the rain and hail. I estimate at least 60 mph winds buffeted my vehicle, with pea-to-dime size hail falling. Vehicle headlights seen in the distant background are from US Highway 218.

As the lowering passed to my north, driving rain rendered visibility to near zero. Moving at this time would have been foolhardy. Rain and hail were pelting the vehicle so loudly I was barely able to make myself understood to the NWS Davenport severe weather report dispatcher. Above, the interior of my vehicle seen at 8:02 pm, as I waited out the deluge. iPhone 6 Plus image.

Radarscope image capture from 7:46 pm CDT, showing the severe and tornado-warned boxes, and my position in relation to both (blue target symbol) at Hills, Iowa.