The medium frequency radar deployed at Tirunelveli (8.7°N, 77.8°E) have been providing continuous data from the year 1993 to the year 2012 that helped to study the long term tendencies in the tidal variabilities in the MLT region. In the present paper we present the results of seasonal, interannual and long-term variabilities of lunar semi-diurnal tides in the upper mesosphere over Tirunelveli. The present study also included comparison with model values. The study shows that the tidal amplitudes are larger in the meridional components of the mesospheric winds than the zonal winds. The seasonal tendencies are similar in both the components. There are unusual amplitude enhancements in the lunar tide in meridional winds during the winters of 2006 and 2009, when major sudden stratospheric warmings (SSW) occurred at high latitude northern hemisphere, whereas zonal lunar tide does not show any clear association with SSW. Vertical wavelengths of lunar tides in zonal and meridional wind are in the range of 20-90 km. Both zonal and meridional component attains a minimum vertical wavelength in the month of June while maximum in November and December. The monthly mean zonal and meridional winds are subjected to regression analysis to study the tidal response to long-period oscillations, namely, quasi-biennial oscillation (QBO), solar cycle variation and El-nino southern oscillation (ENSO). It is found the lunar tide in both zonal and meridional winds show significant QBO response, whereas zonal tide only shows significant negative response to solar cycle and positive response to ENSO.