Register      Login
Journal of Southern Hemisphere Earth Systems Science Journal of Southern Hemisphere Earth Systems Science SocietyJournal of Southern Hemisphere Earth Systems Science Society
A journal for meteorology, climate, oceanography, hydrology and space weather focused on the southern hemisphere
RESEARCH ARTICLE (Open Access)

East coast lows and extratropical transition of tropical cyclones, structures producing severe events and their comparison with mature tropical cyclones

Jeff Callaghan https://orcid.org/0000-0003-1263-0782 A *
+ Author Affiliations
- Author Affiliations

A Retired. Formerly Bureau of Meteorology, Brisbane, Qld 4001, Australia.

B Postal address: 3/34 Macalister Road, Tweed Heads, NSW 2486, Australia.

* Correspondence to: jeffjcallaghan@gmail.com

Journal of Southern Hemisphere Earth Systems Science 71(3) 229-265 https://doi.org/10.1071/ES21003
Submitted: 10 February 2021  Accepted: 7 September 2021   Published: 16 December 2021

© 2021 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of BoM. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Examination of events occurring over the last 53 years in the Australian Region have revealed in the minds of forecasters a common pattern in the development of severe extratropical cyclones which have affected the sub-tropical and temperate East Coast. To evaluate this theory 20 years of data were systematically examined and showed that this was true. To represent these many cases nine such events which delivered the largest impacts over the 53 years were chosen for study. These extratropical cyclones formed downstream of a tropopause undulation which can be easily identified as a warm region at the 200 hPa-level and the formation zone was in a region of heavy rain embedded in a region of warm air advection at 700 hPa. There were hardly any exceptions to this general rule, and one that occurred is presented and was also one of the most rapidly developing systems. This pattern is then evaluated against tropical cyclone events which move in the Australasian sub tropics and three different scenarios are described and compared with a mature severe tropical cyclone which intensified as it moved into the Australia sub tropics. Hurricane Sandy due to its devastating effect on the US sub-tropics in 2012 is examined as a benchmark case whose impact could affect the Australasian sub tropics in the future as sea levels rise with higher density populations.

Keywords: beach erosion, East coast lows, fatalities, heavy rainfall, ocean damage, tropical cyclones, tropopause undulations, warm air advection.


References

Blake ES, Kimberlain TB, Berg RJ, Cangialosi JP, Beven II JL (2013) Tropical Cyclone Report Hurricane Sandy (AL182012) 22–29 October 2012. National Hurricane Center, USA.

Bureau of Meteorology (1966) Tropical cyclones in the Northeastern and North-western Australian regions 1963–1964 Season. Meteorological Summary.

Bureau of Meteorology (1969) Tropical cyclones in the Northern Australian Regions 1967–1968 season. Meteorological Summary.

Bureau of Meteorology (1974) ‘Brisbane floods January 1974’. Australian Government Publishing Service.

Bureau of Meteorology (1999) Preliminary report on meteorological aspects of the 1998 Sydney to Hobart Yacht Race.

Bureau of Meteorology (2021) Special climate statement 74 – extreme rainfall and flooding in eastern and central Australia in March 2021.

Callaghan J (2004) The OTHER CYCLONES. International Conference on Storms, Brisbane Australia July 2004.

Callaghan J (2005) Extra-tropical transition and the continuum between extra-tropical cyclones and tropical cyclones. WMO/TMRP International Workshop on Tropical/Extra tropical Interactions Perth 5–9 December 2005.

Callaghan J (2008) Presentation Sydney East Coast Low Workshop, Bureau of Meteorology Sydney.

Callaghan J (2017a) A diagnostic from vertical wind profiles for detecting extreme rainfall. Tropical Cyclone Research and Review 6, 41–54.
A diagnostic from vertical wind profiles for detecting extreme rainfall.Crossref | GoogleScholarGoogle Scholar |

Callaghan J (2017b) Asymmetric inner core convection leading to tropical cyclone intensification. Tropical Cyclone Research and Review 6, 55–66.
Asymmetric inner core convection leading to tropical cyclone intensification.Crossref | GoogleScholarGoogle Scholar |

Callaghan J (2018) A short note on the rapid intensification of hurricanes harvey and irma. Tropical Cyclone Research and Review 7, 164–171.
A short note on the rapid intensification of hurricanes harvey and irma.Crossref | GoogleScholarGoogle Scholar |

Callaghan J (2019a) A comparison of weather systems in 1870 and 1956 leading to extreme floods in the Murray–Darling Basin. Journal of Southern Hemisphere Earth Systems Science 69, 84–115.
A comparison of weather systems in 1870 and 1956 leading to extreme floods in the Murray–Darling Basin.Crossref | GoogleScholarGoogle Scholar |

Callaghan J (2019b) The interaction of hurricane Michael with an upper trough leading to intensification right up to landfall. Tropical Cyclone Research and Review 8, 95–102.
The interaction of hurricane Michael with an upper trough leading to intensification right up to landfall.Crossref | GoogleScholarGoogle Scholar |

Callaghan J (2019c) A short note on the intensification and extreme rainfall associated with hurricane lane. Tropical Cyclone Research and Review 8, 103–107.
A short note on the intensification and extreme rainfall associated with hurricane lane.Crossref | GoogleScholarGoogle Scholar |

Callaghan J (2020) Extraordinary sequence of severe weather events in the late-nineteenth century. Journal of Southern Hemisphere Earth Systems Science 70, 252–279.
Extraordinary sequence of severe weather events in the late-nineteenth century.Crossref | GoogleScholarGoogle Scholar |

Callaghan J (2021) Weather systems and extreme rainfall generation in the 2019 north Queensland floods compared with historical north Queensland record floods. Journal of Southern Hemisphere Earth Systems Science 71, 123–146.
Weather systems and extreme rainfall generation in the 2019 north Queensland floods compared with historical north Queensland record floods.Crossref | GoogleScholarGoogle Scholar |

Callaghan J, Power SB (2014) Major coastal flooding in south-eastern Australia 1860–2012, associated deaths and weather systems. Australian Meteorological and Oceanographic Journal 64, 183–213.
Major coastal flooding in south-eastern Australia 1860–2012, associated deaths and weather systems.Crossref | GoogleScholarGoogle Scholar |

Callaghan J, Power SB (2016) A vertical wind structure that leads to extreme rainfall and major flooding in southeast Australia. Journal of Southern Hemisphere Earth Systems Science 66, 380–401.
A vertical wind structure that leads to extreme rainfall and major flooding in southeast Australia.Crossref | GoogleScholarGoogle Scholar |

Callaghan J, Tory K (2014) On the use of a system-scale ascent/descent diagnostic for short-term forecasting of Tropical Cyclone development, intensification, and decay. Tropical Cyclone Research and Review 3, 78–90.
On the use of a system-scale ascent/descent diagnostic for short-term forecasting of Tropical Cyclone development, intensification, and decay.Crossref | GoogleScholarGoogle Scholar |

Chen H, Zhang D-L (2013) On the rapid intensification of hurricane wilma (2005). Part II: convective bursts and the upper-level warm core. Journal of the Atmospheric Sciences 70, 146–162.
On the rapid intensification of hurricane wilma (2005). Part II: convective bursts and the upper-level warm core.Crossref | GoogleScholarGoogle Scholar |

Dowdy AJ, Mills GA, Timbal B (2011) Large-scale indicators of Australian East Coast Lows and associated extreme weather events. CAWCR Technical Report No. 037.

Dowdy AJ, Mills GA, Timbal B (2013) Large-scale diagnostics of extratropical cyclogenesis in eastern Australia. International Journal of Climatology 33, 2318–2327.
Large-scale diagnostics of extratropical cyclogenesis in eastern Australia.Crossref | GoogleScholarGoogle Scholar |

Dowdy AJ, Pepler A, Di Luca A, Cavicchia L, Mills G, Evans JP, Louis S, McInnes KL, Walsh K (2019) Review of Australian east coast low pressure systems and associated extremes. Climate Dynamics 53, 4887–4910.
Review of Australian east coast low pressure systems and associated extremes.Crossref | GoogleScholarGoogle Scholar |

Dysthe KB, Harbitz A (1987) Big waves from polar lows. Tellus 39, 500–508.
Big waves from polar lows.Crossref | GoogleScholarGoogle Scholar |

Foley GR, Hanstrum BN (1994) The capture of tropical cyclones by cold fronts off the west coast of Australia. Weather and Forecasting 9, 577–592.
The capture of tropical cyclones by cold fronts off the west coast of Australia.Crossref | GoogleScholarGoogle Scholar |

Foster DN, Gordon AD, Lawson NV (1975) The storms of May June 1974 Sydney NSW, Second Australian Conference on Coastal and Ocean Engineering, Gold Coast.

Guy Carpenter and Company (2013) ‘Post sandy damage report’. (Guy Carpenter)

Harr PA, Elsberry RL (2000) Extra tropical transition of tropical cyclones over the western North Pacific. Part I: evolution of structural characteristics during the transition process. Monthly Weather Review 128, 2613–2633.
Extra tropical transition of tropical cyclones over the western North Pacific. Part I: evolution of structural characteristics during the transition process.Crossref | GoogleScholarGoogle Scholar |

Hart RE (2003) A cyclone phase space derived from thermal wind and thermal asymmetry. Monthly Weather Review 131, 585–616.
A cyclone phase space derived from thermal wind and thermal asymmetry.Crossref | GoogleScholarGoogle Scholar |

Hirschberg PA, Fritsch JM (1991a) Tropopause undulations and the development of extratropical cyclones. Part 1: overview and observations from a cyclone event. Monthly Weather Review 119, 496–517.
Tropopause undulations and the development of extratropical cyclones. Part 1: overview and observations from a cyclone event.Crossref | GoogleScholarGoogle Scholar |

Hirschberg PA, Fritsch JM (1991b) Tropopause undulations and the development of extratropical cyclone. Part II: diagnostic analysis and conceptional model. Monthly Weather Review 119, 518–550.
Tropopause undulations and the development of extratropical cyclone. Part II: diagnostic analysis and conceptional model.Crossref | GoogleScholarGoogle Scholar |

Hirschberg PA, Fritsch JM (1993) On understanding height tendency. Monthly Weather Review 121, 2646–2661.
On understanding height tendency.Crossref | GoogleScholarGoogle Scholar |

Holland GJ (1997) The maximum potential intensity of tropical cyclones. Journal of the Atmospheric Sciences 54, 2519–2541.
The maximum potential intensity of tropical cyclones.Crossref | GoogleScholarGoogle Scholar |

Holland GJ, Lynch AH, Leslie LM (1987) Australian East Coast cyclones. Part I. Synoptic overview and case study. Monthly Weather Review 115, 3024–3036.
Australian East Coast cyclones. Part I. Synoptic overview and case study.Crossref | GoogleScholarGoogle Scholar |

Hopkins LC, Holland GJ (1997) Australian heavy-rain days and associated East Coast cyclones: 1958–92. Journal of Climate 10, 621–635.
Australian heavy-rain days and associated East Coast cyclones: 1958–92.Crossref | GoogleScholarGoogle Scholar |

Hoskins BJ, McIntyre ME, Robertson AW (1985) On the use and significance of isentropic potential vorticity maps. Quarterly Journal of the Royal Meteorological Society 111, 877–946.
On the use and significance of isentropic potential vorticity maps.Crossref | GoogleScholarGoogle Scholar |

Huo Z, Zhang D-L, Gyakum J (1995) A diagnostic analysis of the Superstorm of March 1993. Monthly Weather Review 123, 1740–1761.
A diagnostic analysis of the Superstorm of March 1993.Crossref | GoogleScholarGoogle Scholar |

Irish JL, Lynett PJ, Weiss R, Smallegan SM, Cheng W (2013) Buried relic seawall mitigates Hurricane Sandy’s impacts. Coastal Engineering 80, 79–82.
Buried relic seawall mitigates Hurricane Sandy’s impacts.Crossref | GoogleScholarGoogle Scholar |

Joubert PN (2005) Some remarks on the 1998 Sydney Hobart Race. Transactions of the Royal Society of Victoria 117, ix–xviii.

Klein PM, Harr PA, Elsberry RL (2000) Extratropical transition of western North Pacific tropical cyclones: an overview and conceptual model of the transformation stage Weather and Forecasting 15, 373–395.
Extratropical transition of western North Pacific tropical cyclones: an overview and conceptual model of the transformation stageCrossref | GoogleScholarGoogle Scholar |

Leroux M-D, Nguyen-Hankinson MC, Davidson NE, Callaghan J, Tory K, Wain A, Huang X (2019) Environmental interactions during the extreme rain event associated with ex-tropical cyclone Oswald (2013). Journal of Southern Hemisphere Earth Systems Science 69, 216–238.
Environmental interactions during the extreme rain event associated with ex-tropical cyclone Oswald (2013).Crossref | GoogleScholarGoogle Scholar |

Louis S, Couriel E, Lewis G, Glatz M, Kulmar M, Golding J, Hanslow D (2016) NSW East Coast Low event – 3 to 7 June 2016 weather, wave and water level matters. Manly Hydraulics Laboratory, New South Wales Government.

McAneney J, Sandercock B, Crompton R, Mortlock T, Musulin R, Pielke R, Gissing A (2019) Normalised insurance losses from Australian natural disasters: 1966–2017. Environmental Hazards 18, 414–433.
Normalised insurance losses from Australian natural disasters: 1966–2017.Crossref | GoogleScholarGoogle Scholar |

Mills GA (2001) Mesoscale cyclogenesis in reversed shear - the 1998 Sydney to Hobart yacht race storm. Australian Meteorological Magazine 50, 29–52.

Pepler AS, Rakich CS (2010) Extreme inflow events and synoptic forcing in Sydney catchments. IOP Conference Series: Earth and Environmental Science 11, 012010
Extreme inflow events and synoptic forcing in Sydney catchments.Crossref | GoogleScholarGoogle Scholar |

Pepler A, Coutts-Smith A, Timbal B (2013) The role of East Coast lows on rainfall patterns and inter-annual variability across the East Coast of Australia. International Journal of Climatology 34, 1011–1021.
The role of East Coast lows on rainfall patterns and inter-annual variability across the East Coast of Australia.Crossref | GoogleScholarGoogle Scholar |

Power S, Callaghan J (2015) Variability in severe coastal flooding in south-eastern Australia since the mid-19th century, associated storms and death tolls. Journal of Applied Meteorology and Climatology 55, 1139–1149.
Variability in severe coastal flooding in south-eastern Australia since the mid-19th century, associated storms and death tolls.Crossref | GoogleScholarGoogle Scholar |

Power S, Callaghan J (2016) The frequency of major flooding in coastal southeast Australia has significantly increased since the late 19th century. Journal of Southern Hemisphere Earth Systems Science 66, 2–11.
The frequency of major flooding in coastal southeast Australia has significantly increased since the late 19th century.Crossref | GoogleScholarGoogle Scholar |

Quinting JF, Catto JL, Reeder MJ (2019) Synoptic climatology of hybrid cyclones in the Australian region. Quarterly Journal of the Royal Meteorological Society 145, 288–302.
Synoptic climatology of hybrid cyclones in the Australian region.Crossref | GoogleScholarGoogle Scholar |

Roberts NM (2000) A guide to aspects of water vapor imagery interpretation: the significance of dry regions. JCMM Internal Report No. 109. Joint Centre for Mesoscale Meteorology, University of Reading, Reading, Berkshire, UK.

Rolfson DM, Smith PJ (1996) A composite diagnosis of synoptic-scale extratropical cyclone development over the United States. Monthly Weather Review 124, 1084–1099.
A composite diagnosis of synoptic-scale extratropical cyclone development over the United States.Crossref | GoogleScholarGoogle Scholar |

Sinclair M (1993) A diagnostic study of the extratropical precipitation resulting from tropical cyclone bola. Monthly Weather Review 121, 2690–2707.
A diagnostic study of the extratropical precipitation resulting from tropical cyclone bola.Crossref | GoogleScholarGoogle Scholar |

Sinclair MR, Revell MJ (2000) Classification and composite diagnosis of extratropical cyclogenesis events in the Southwest Pacific. Monthly Weather Review 128, 1089–1105.
Classification and composite diagnosis of extratropical cyclogenesis events in the Southwest Pacific.Crossref | GoogleScholarGoogle Scholar |

Speer MS, Wiles P, Pepler A (2009) Low pressure systems off the New South Wales coast and associated hazardous weather: establishment of a database. Australian Meteorological and Oceanographic Journal 58, 29–39.
Low pressure systems off the New South Wales coast and associated hazardous weather: establishment of a database.Crossref | GoogleScholarGoogle Scholar |

Strahl JLS, Smith PJ (2001) Diagnostic study of an explosively developing extratropical cyclone and an associated 500- hPa trough merger. Monthly Weather Review 129, 2310–2328.
Diagnostic study of an explosively developing extratropical cyclone and an associated 500- hPa trough merger.Crossref | GoogleScholarGoogle Scholar |

Tory K (2014) The turning winds with height thermal advection rainfall diagnostic: why does it work in the tropics? Australian Meteorological and Oceanographic Journal 64, 231–238.
The turning winds with height thermal advection rainfall diagnostic: why does it work in the tropics?Crossref | GoogleScholarGoogle Scholar |

Watson P, Lord D, Kulmar M, Mcluckie D, James J (2007) ‘Analysis of a storm June 2007’. (Manly Hydraulics Laboratory)

Weldon RB, Holmes SJ (1991) ‘Water vapor imagery. Interpretation and applications to weather analysis and forecasting. NOAA Technical Report NESDIS 57’. (National Oceanic and Atmospheric Administration: Washington, DC)

Wernli H, Dirren S, Liniger MA, Zillig M (2002) Dynamical aspects of the life cycle of the winter storm ‘Lothar’ (24–26 December 1999). Quarterly Journal of the Royal Meteorological Society 128, 405–429.
Dynamical aspects of the life cycle of the winter storm ‘Lothar’ (24–26 December 1999).Crossref | GoogleScholarGoogle Scholar |

Zhang D-L, Chen H (2012) Importance of the upper-level warm core in the rapid intensification of a tropical cyclone. Geophysical Research Letters 39, L02806
Importance of the upper-level warm core in the rapid intensification of a tropical cyclone.Crossref | GoogleScholarGoogle Scholar |

Zovko-Rajak D, Tory KJ, Fawcett RJB, Kepert JD, Rikus LJ (2018) High-resolution ensemble prediction of the Australian East Coast Low of April 2015. Journal of Southern Hemisphere Earth Systems Science 68, 165–184.
High-resolution ensemble prediction of the Australian East Coast Low of April 2015.Crossref | GoogleScholarGoogle Scholar |