Synoptic–Dynamic and Airmass Characteristics Distinguishing Long- and Short-Duration Freezing Rain Events in the South-Central United States

Abstract Though prolonged freezing rain events are rare, they can result in substantial damage when occur. While occurs less frequently the south-central United States than some regions of North America, a large number extremely long-duration lasting at least 18 h have been observed there. We explore key synoptic–dynamic conditions that lead to these extreme through comparison with severe short-duration events. produce composites and 7-day backward trajectories for parcels ending warm cold layers each event category. The preferentially associated deeper more stationary 500-hPa longwave trough centered over southwestern onset. This supports sustained flow warm, moist air from within planetary boundary layer Gulf Mexico northward into layer. cases instead characterized by transient upper-level axis U.S. region Following onset, rapid passage leads quasigeostrophic forcing descent advection cold, dry erodes ends precipitation. very similar between two categories, those longer history compared ones, resulting warmer moister onset layers.