Temperature and H2O measurements from the Upper Atmospheric Research Satellite Microwave Limb Sounder (UARS MLS) data sets during southern hemisphere summer of 1991-92 are analyzed using the asynoptic mapping method. Results show a prominent wavenumber 3 two-day wave confined to latitudes between 60 ¿S and 4 ¿N and to altitudes above 2 hPa. The temperature wave amplitude increases upward to the upper limit of the observations and maximizes at 2.0 K near 0.465 hPa. The H2O wave amplitude reaches a maximum of 0.25 ppmv near 1 hPa. Evidence suggestive of wave breaking and meridional mixing associated with the interaction between this wave and a lower frequency wavenumber 1 is shown. ¿ American Geophysical Union 1995