Thunderstorm Wind — Clay, Alabama

2018-06-28 · near Lineville, Clay, Alabama

Event narrative

Lineville city police reported a fatality when a large tree fell on a moving vehicle. The vehicle was traveling on Martha Street.

Wider weather episode

A rare Southeast States derecho swept southward through the entire state of Alabama during the afternoon and evening hours of June 28th. This particular event featured a complex of thunderstorms that resulted in wind damage along a track nearly 400 miles long, originating in Central Tennessee and ending along the Gulf Coast. The southward movement of these storms was driven by clockwise flow around a ridge of high pressure centered over the Central United States. In Central Alabama, the storms moved through during peak daytime heating with a very unstable air mass in place. CAPE values of 4,000-5,000 J/kg were common while bulk wind shear values were low due to the proximity of the upper ridge. Steep low-level lapse rates aided in momentum transfer of strong winds aloft to the surface. Wind damage occurred not only with the thunderstorms, but with the outflow as well.

View location on OpenStreetMap → (33.3117, -85.7425)

Source: NOAA Storm Events Database, event_id 768979. Narrative written by the NWS forecast office that issued the report.