INITIATION AND DEVELOPMENT OF REAR INFLOW WITHIN THE 28-29 JUNE 1989 NORTH-DAKOTA MESOCONVECTIVE SYSTEM

Five dual-Doppler analyses spanning a period of 1.5 h are used to docu ment the initiation and development of rear inflow within a High Plain s squall line. The squall line developed as part of the 28-29 June 198 9 mesoconvective system that passed through the North Dakota Thunderst orm Project observational network. This storm was explosively initiate d along a preexisting, isolated gust front in an environment of much i nstability and weak upper-air flow, and moved within dual-Doppler cove rage soon after its initiation. The kinematic analyses were performed over a 90-min period as the squall line continued to develop and move to the east-northeast. The Doppler analyses reveal that the rear inflo w was initiated near the high-reflectivity cores of the squall line, w ithin 20 min of the formation of the system. With time, the rear inflo w expanded rearward, increased in intensity, and descended to near the surface behind the northern section of the squall line. In regions wh ere the squall line dissipated, the rear inflow also dissipated near t he leading edge of the system but remained near the base of the traili ng anvil. Line-parallel analyses indicate that the rear inflow exhibit ed significant variance in both elevation and magnitude along the leng th of the squall line. The observations herein suggest that the primar y forcing for the rear inflow in this case was the result of processes associated with the strong convection at the leading edge of the squa ll line and that secondary processes within the trailing anvil-stratif orm region may also have contributed to the forcing of rear inflow.