@article {bnh-8124, title = {A characterisation of synoptic weather features often associated with extreme events in southeast Australia: Stage 1 {\textendash} common features of recent events}, number = {679}, year = {2021}, month = {07/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

Negatively tilted upper-tropospheric troughs are a synoptic weather pattern that have been associated with the development of thunderstorms and severe weather, including extreme fire weather and tornadoes. While various case studies and some preliminary climatological analysis have been conducted in the past, a thorough investigation of the development of these synoptic features during extreme weather events has not yet been done in Australia or elsewhere. This study aimed to identify how often negatively tilted troughs occur and how often they are associated with extreme storms and fire weather.

The objectives of the project were to:

The major components of the project were:

Review of previously documented cases

January 2003 Canberra fires

July 2014 Perth tornadoes

Climatology

While modern numerical weather prediction (NWP) systems are increasingly capable of resolving the surface weather parameters associated with severe weather events, there are known deficiencies. An example of this is the over-estimation of low winds and under-estimation of high winds common to numerous models. Better understanding of the role of features such as NTT in generating surface weather helps interpretation and refinement of the NWP output, particularly for users of weather data such as emergency services agencies.

Furthermore, as products from NWP such as sub-seasonal to seasonal outlooks become more refined, there is value in recognising the occurrence of potential impacts of NTT that may be resolved at the synoptic or sub-synoptic scale in such model configurations even if the potential severity of the weather parameters are note explicitly resolved. For example, if a sub-seasonal to seasonal model ensemble shows a high probability of a NTT occurrence in a particular region a certain number of weeks in advance, that is useful information for planning and preparedness for emergency services managers.

Thus, this sort of synoptic climatological study in combination with detailed analyses of particular events continues to be of great relevance to natural hazard prediction and management.

Future work

}, keywords = {exterme events, features, Fire, southeast Australia, synoptic, tornado, weather}, issn = {679}, author = {Love, P. and Paul Fox-Hughes and Remenyi, T. and Nick Earl and Dean Rollins and Gabi Mocatta and Rebecca Harris} } @conference {bnh-6511, title = {A case study of South Australia{\textquoteright}s severe thunderstorm and tornado outbreak }, booktitle = {AFAC19 powered by INTERSCHUTZ - Bushfire and Natural Hazards CRC Research Forum}, year = {2019}, month = {12/2019}, publisher = {Australian Institute for Disaster Resilience}, organization = {Australian Institute for Disaster Resilience}, address = {Melbourne}, abstract = {

On September 28, 2016 one of the most significant thunderstorm outbreaks recorded in South Australia impacted central and eastern parts of the state. Multiple supercell thunderstorms were embedded in a Quasi-Linear Convective System aligned with a strong cold front that was associated with an intense low-pressure system. The storms produced at least seven tornadoes, destructive wind gusts, large hail and intense rainfall. Transmission lines were brought down in four different locations, which contributed to a state-wide power outage.

Accurate prediction and understanding of tornadoes and other hazards associated with severe thunderstorms is very important, for timely preparation and announcement of warnings. By conducting high-resolution simulations, this study aims to offer a better understanding of the meteorology of the South Australian thunderstorm and tornado outbreak. It also contributes to improving knowledge of how to best predict similar severe weather events, which in turn enables better risk management and preparedness for such events. Updraft
helicity, a severe storm surrogate that indicates the potential for updraft rotation in simulated storms, is used to investigate the ability of the model to predict supercell and tornado likelihood.

Download the full non-peer reviewed research proceedings\ from the Bushfire and Natural Hazards CRC Research Forumhere.

}, keywords = {modelling, risk management, Severe Weather, thunderstorm, tornado}, url = {https://knowledge.aidr.org.au/resources/australian-journal-of-emergency-management-monograph-series/}, author = {Dragana Zovko-Rajak and KJ Tory and Jeffrey Kepert} }