IMD further said, "The Western Disturbance as a cyclonic circulation over north Pakistan and neighbourhood between 3.1 and 5.8 km above mean sea level with a trough aloft
with its axis at 7.6 km above mean sea level roughly along Longitude 72degE to the North of Latitude 28degN persists."
Tropical cyclogenesis over subthreshold sea surface temperatures is associated with low tropopause heights, indicative of the presence of a cold trough aloft. To focus on this type of development environment, the applicability of the 26.5[degrees]C threshold is investigated for tropical transitions from baroclinic precursor disturbances in all basins between 1989 and 2013.
Of particular relevance to this study will be the ability of the scheme to identify TT events (Davis and Bosart 2003, 2004), because this development paradigm depends strongly on the presence of a cold trough aloft. Once classifications have been made, the resulting development pathway-specific climatologies can be evaluated to determine whether 26.5[degrees]C is a universally applicable threshold, or whether a different quantity yields a more relevant necessary condition for tropical cyclogenesis from baroclinic precursors.