The modeling and observation of a lee trough event over eastern Tasmania

Abstract

Due to its complex orography, a lee trough can occur along leeward coasts of Tasmania. Of particular interest to meteorologists and others, is the lee trough that can form along eastern parts of Tasmania. This effect is often observed under broad westerly flow due mainly to a topographic barrier, which lies to the west of the area of interest. The lee trough seems to be most pronounced when the troposphere is stable with an inversion just above the highest parts of the western and central highlands, known as the Western Mountains and Central Plateau, respectively. Blocking of the low-level airflow, coupled with the formation of a windward ridge of high pressure may also contribute to the formation of the lee trough. From time to time, mesoscale thermal lows and pronounced standing wave activity has also been observed to form over parts of the state co-incident with the lee trough. These can further complicate the overall wind pattern over parts of the Tasmania. This study attempts to investigate and verify some aspects of this lee trough by the utilization of a very high resolution numerical weather prediction model, known as HIRES (HIghRESolution).