EF1 tornado in Franklin County, Iowa

This was a rather slow moving tornado which moved east initially through open cropland. The tornado then turned southeast, east and eventually northeast as it journeyed through the farmland. The tornado did hit a hog confinement with the roof collapsing producing EF1 damage.

A cold front sank south across Iowa during the afternoon and evening of July 28th. The environment was primed for severe storms with warm moist air in place; as temperatures climbed into the 90s and dewpoints into the 70s. By afternoon MLCAPE values of 3000 J/kg were in place across much of Iowa with deep layer shear exceeding 40 kts. Such an environment supported rapid storm development along the boundary by late afternoon. Storms produced ping-pong ball to baseball sized hail along with two tornadoes, damaging confinement pens and creating easily identifiable tracks on high resolution satellite imagery through surrounding fields. As storms pushed south into the evening, the hazards transitioned to a wind threat. A micro burst occurred in Marshall County very near the ASOS, resulting in an isolated pocket of 80 to 90 mph winds.