Bringing The Curtain Down On The Day's Chase

The final act of severe weather for Eastern Iowa on Thursday, August 4, 2016, was about to roll over my position at Oliver Court in Marion, Iowa. The gust front stretched at this moment from just east of Des Moines to just north of Cedar Rapids. In these three images the leading edge of a shelf cloud plows methodically onward with Bowman Meadows housing development in the foreground. Image capture above was 7:49 pm CDT, looking just a little south of west.

The defined ragged appearance of the shelf cloud has now become more evident a minute later, despite the darkening, low-contrast conditions experienced by my camera. Focusing on the approach of the storm was achieved by an auto-focus lock on the brighter sky in the opposite direction, then switching to manual focus. The ragged appearance of the shelf cloud was created by warm, moist air condensing from its interaction with the rain-chilled (downdraft) air spreading behind it.

Another capture from 7:50 pm. To be on the safe side, I took these shots inside from the open window of my vehicle. As the gust front quickly passed overhead, I waited out drenching rain, lightning and high winds for about another half hour. Winds speeds here, in my estimation, never exceeded 50 mph. Darkness now and the end of my day's chase! This storm system would produce a tornado-warned area just west of Davenport as it moved east. Nikon D7200 DSLR camera.