The excitation of pressure waves by a point source in a nonisothermal, stratified atmosphere is studied. Using an ad hoc monotonically increased thermal profile, Green's function is derived. It is shown that apart from the usual acoustic and acoustic-gravity branches, waves guided by the atmospheric thermocline are also excited. The leading term of an asymptotic expansion of Green's function is then used to obtain an analytic expression of the acoustic front and the impulse tail. ¿American Geophysical Union 1995