Previous studies have shown that there is a dipole relationship between precipitation in the North American monsoon region and precipitation in the central U.S. Specifically, onset of the North American monsoon (NAM) tends to be associated with a decrease in precipitation over the central U.S. We examine this teleconnection using a climatology of MCCs and PECSs (persistent elongated convective systems) based on analysis of GOES8-IR imagery. We have extended our previous MCC and PECS climatologies to eight years - 1992, 1993, 1997-2002. Results indicate that in some years, onset of the NAM produces a very marked change in the number, character and spatial distribution of mesoscale convective systems. In other years there is little relationship. As expected the strength of this relationship appears to depend on the strength of the NAM as reflected in seasonal precipitation over the NAM region. Our results demonstrate a climatologically important scale-interaction mechanism by which a specific set of mesoscale processes plays a crucial role in a continental-scale teleconnection.