A PV-streamer's role in a succession of heavy rain-producing MCSs over thecentral United States

A PV-streamer at 250 hPa, moving over the west central United States 25 Jun e-5 July 1999 was visible on GOES-8 water vapor imagery as a narrow, elonga ted dark band. It sparked a series of mesoscale convective systems (MCSs) o n successive days, producing heavy precipitation from Nebraska eastward and southeastward toward the coast along the Gulf of Mexico. The MCSs began as the PV-streamer moved off the central Rocky Mountains onto the Great Plain s where it interacted with a surface front and a low-level jet. Each convec tive system interrupted the PV-streamer, and low- and mid-level vorticity a ccumulated along the front. One of the more spectacular MCSs that occurred 28 June 1999 is examined in detail. (C) 2001 Elsevier Science Ltd. All righ ts reserved.