Regeneration of the southerly buster of southeast Australia

The southerly buster has been successfully simulated using a numerical weat her prediction (NWP) model and verified (particularly the sea level pressur e field). This simulation was then used to study the behavior of the southe rly buster in the region of the Hunter Valley, New South Wales, Australia, with the reintensification of the surge. In simulating the dynamics of the southerly buster in the vicinity of the Hunter Valley, both the horizontal and vertical resolution of the NWP are important. This was found through a series of simulations of a case study of 27 February 1998. The best simulat ion was achieved with 20 vertical levels, a coarse nesting into the Austral ian Bureau of Meteorology Limited Area Prediction System model, then down t o finer grids in progressively higher resolutions. The pressure ridge associated with the southerly buster is induced by the s outherly Row up the southern parts of the Great Dividing Range resulting in anticyclonic vorticity that creates a region of high pressure ahead of the main high pressure cell behind the frontal system. This same mechanism is used to explain the reintensification of the surge at the northern part of the Great Dividing Range, which is characterized by a renewed peak in wind speed north of the Hunter Valley.