A two-dimensional, multilevel primitive equation model is used to investigate various characteristics of thermally driven circulations. The sensitivity of the mesoscale circulations to the magnitude of the surface, sensible heat flux is established through examination of various quantifiable circulation features such as the planetary boundary layer depth and the horizontal and vertical wind maxima. The simulations fall into two groups; one deals with circulations over flat terrain in the vicinity of a coastline and the other deals with circulations induced by heating of the irregular terrain in the vicinity of the Tennessee Valley. The results establish a surprisingly linear relationship between forecast errors and errors in the specification of the surface sensible heat flux. The results of the Tennessee Valley simulations are verified using satellite visible imagery. The model-predicted subsidence over the valley corresponds very closely in location to anomalous cloud-free regions observed in numerous satellite photographs.