Flash Flood in Hempstead County, Arkansas

A portion of Highway 355 was closed in Fulton due to a flooded underpass.

A weakening mesoscale convective system (MCS) advanced east southeast into Southwest Arkansas during the morning hours on June 24th, just north of an outflow reinforced frontal boundary which extended from Northeast Texas into North Central Louisiana and eastward into Mississippi. Behind the MCS, showers and thunderstorms increased in coverage from North Louisiana into Southwest Arkansas. Wind profiles in the 925-850 millibar layer showed some modest strengthening into the 25-30 knot range from the south southwest, helping to remove lingering lower level convective inhibition centered near 850 mb. Low level flow overrunning the surface boundary set up a convergence axis in the 925-850 millibar layer, aligned from Southeast Oklahoma into Northwest Louisiana. This zone of convergence focused increasing coverage of elevated thunderstorms throughout the morning, beneath increasingly diffluent flow aloft in the 300-400 millibar layer. The convergence axis was aligned with a gradient in MLCAPE of 500 to 1500 J/kg noted to the southwest of the axis. Precipitable water (PWAT) values ranged from 1.7 to near 2 inches across the region. As a result, hourly rainfall rates of 1 to 2+ inches occurred within areas of training storms with localized rainfall totals of 2 to 6+ inches common across Southwest Arkansas. Thus, numerous reports of flash flooding were recorded throughout the morning into the mid-afternoon.