Tropical heating due to latent heat release has been proposed as a source that may influence midlatitude weather through teleconnection patterns. However, such heating is usually-internal (with the maximum in the midtroposphere) and, by itself, inefficient in exciting external, barotropic-type responses, which are necessary for the teleconnection mechanism. To study this problem, a simple two-level model is used to investigate the effect of vertical shear, differential damping and the planetary boundary layer on the characteristics of the atmospheric response to internal heating. All three effects are found to enable a transfer of energy from the internal-mode motions, which are directly forced by the internal heating, to external-mode motions. To generate external-mode divergent motions, it is necessary to have a planetary boundary layer or other equivalent effects that force vertical motion at the bottom of the atmosphere. The efficiency of generation increases with the horizontal scale. On the... Abstract Tropical heating due to latent heat release has been proposed as a source that may influence midlatitude weather through teleconnection patterns. However, such heating is usually-internal (with the maximum in the midtroposphere) and, by itself, inefficient in exciting external, barotropic-type responses, which are necessary for the teleconnection mechanism. To study this problem, a simple two-level model is used to investigate the effect of vertical shear, differential damping and the planetary boundary layer on the characteristics of the atmospheric response to internal heating. All three effects are found to enable a transfer of energy from the internal-mode motions, which are directly forced by the internal heating, to external-mode motions. To generate external-mode divergent motions, it is necessary to have a planetary boundary layer or other equivalent effects that force vertical motion at the bottom of the atmosphere. The efficiency of generation increases with the horizontal scale. On the...