Hurricane Helene made landfall near Perry (Latitude 30.1 N) in the Big Bend area of Florida with a central pressure of 939 hPa. It moved northwards creating devastating damage and loss of life; however, the greatest damage and number of fatalities occurred well to the north around the City of Ashville (Latitude 35.6 N) where extreme rainfall fell and some of the strongest wind gusts were reported. This paper describes the change in the hurricane’s structure as it tracked northwards, how it gathered tropical moisture from the Atlantic and a turning wind profile between the 850 hPa and 500 hPa elevations, which led to such extreme rainfall. This turning wind profile is shown to be associated with extreme rainfall and loss of life from drowning and landslides around the globe. The area around Ashville suffered 157 fatalities, which is a considerable proportion of the 250 fatalities so far recorded in the whole United Stares from Helene. This is of extreme concern and should be investigated in detail as the public expect the greatest impact from hurricanes to be confined to coastal areas near the landfall site. It is another example of increased death tolls from tropical cyclones moving inland and generating heavy rainfall. As the global population increases and inland centres become more urbanised, run off from such rainfall events increases, which causes greater devastation.

Recent intensifying tropical cyclones around the globe are analysed to examine the observed winds structure in their inner core. The winds in sectors with strong bands of thunderstorms were observed from analysed vector winds in weather forecasting computer models to turn in an anticyclonic fashion from the 850hPa level up to the 500hPa level. This wind structure resembles Quasi-Geostrophic warm air advection and from Hysplit the trajectory analysis was in areas of ascending air currents suitable for the initiation of thunderstorms. The rapid intensification occurred as the cyclonic circulation extends up to at least 200hPa.

An extreme weather event which occurred in June 2021 stretched the rescue operations of Victorian Emergency Services due to major flooding and the unprecedented number of fallen large trees. The mechanisms which produced severe convection with gusts strong enough to bring down thousands of trees also produced the heaviest rainfall. The blocked roads and access to fallen power lines resulted in power outages lasting three weeks in some areas and some people were trapped in their houses for up to a week. The atmosphere around Melbourne was characterized by very strong vertical wind shear however convection was confined to mountainous areas southeast, east, and northwest of Melbourne. Overall, the region around Melbourne was in a stable atmosphere and convection was released by strong orographic lifting. Some of the heaviest rain fell on the Strzelecki Ranges and this drained into the city of Traralgon where near-record floods were reported. The event is compared with a Melbourne event in 2020 which caused three fatalities from fallen trees in the afternoon peak period. The fatalities were restricted with the current event due to it occurring just before and after midnight.

During February 2022 major riverine flooding occurred in an area which has the fastest population growth in Australia. This extended from the Mary River in Southeast Queensland (SEQ) to the Clarence River in Northeast NSW (NENSW). Two centres within this area were devastated by floods unprecedented in living memory. One was the Brisbane Metropolitan area where all-time record daily rainfall in the suburbs flooded creeks. This creek flooding was much worse than that caused by the Brisbane River itself where Wivenhoe Dam played a role in preventing more disastrous flooding. The other was in the Northern New South Wales city of Lismore where rainfall in the Wilsons River catchment exceeded all known rainfall rates there. The structure of the weather system generating the rainfall responsible for these two floods is studied along with the climatology of such events. One event which occurred during 1954 stands out and is examined in detail. A climate shift in 1976 resulted in two decades of relatively benign weather in the region and tourism flourished there due to mild summers and warm winters. The area experienced a huge growth in population with fading memories of past disastrous weather events and huge residential development occurred in flood plain areas. During the twenty-first century these extreme events have returned although so far not as frequent as earlier decades but still result in some residents experiencing multiple flooding events. The 1954 event occurred during an extended period of devastating flood events not experienced in recent decades. With the huge increase in population in this area since the 1970s such a series of events like those in the 1950s would stretch the resources of disaster managers given the problems, they faced in 2022.

An extensive search has been carried out to find all major flood and very heavy rainfall events in Victoria since 1876 when Southern Oscillation (SOI) data became available. The synoptic weather patterns were analysed and of the 319 events studied,121 events were found to be East Coast Lows (ECLs) and 82 were other types of low-pressure systems. Tropical influences also played a large role with 105 events being associated with tropical air advecting down to Victoria into weather systems. Examples are presented of all the major synoptic patterns identified. The SOI was found to be an important climate driver with positive SOIs being associated with many events over the 144 years studied. The 1976 Climate Shift and its influence on significant Victorian rainfall events is studied and negative SOI monthly values were shown to dominate following the Shift.However,one of the most active periods in 144 years of Victorian heavy rain occurred after the shift with a sustained period of positive SOI events from 2007 to 2014. Therefore, it is critical for forecasting future Victorian heavy rainfall is to understand if sequences of these positive SOI events continue like those preceding the Shift. Possible relationships between the Shift and Global Temperature rises are also explored. Upper wind data available from some of the heaviest rainfall events showed the presence of anticyclonic turning of the winds between 850hPa and 500hPa levels which has been found to be linked with extreme rainfall around the Globe.

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.

The Australian tropical cyclone (TC) best track database (BT) maintained by the Bureau of Meteorology has records since 1909 of varying quality and completeness. Since 2005 a series of efforts to improve the database have included: removing internal inconsistencies, adding fixes, and identifying errors using comparisons with other datasets; upgrading intensity information since 1973 including adding maximum winds (Vm) prior to 1984–85, rederiving Dvorak Current Intensity numbers from archived material and accounting for different wind–pressure relationships used; a partial reanalysis of satellite imagery including microwave imagery using the HURSAT dataset since 1987; and considering an objective intensity dataset. The BT homogeneity is reviewed in the context of improvements in satellite technology, observational coverage, scientific developments, BT procedures and the subjective variation between analysts across time and offices. The scale of these variances is greatest in the early stages prior to 1981 in the absence of geostationary satellite imagery until 1978, satellite calibration issues from 1978–80 and prior to the introduction of the enhanced infra-red Dvorak technique in 1981. The current era since 2003 is considered to be the most accurate, comprehensive and homogeneous corresponding to the expansion of the TC database to include the current suite of fields; the application of microwave and scatterometry imagery; greater standardisation of BT practices and slight changes in the application of the Dvorak technique. These improvements have generated a more consistent dataset that could be used for weather and climate research and other TC-related work.

Earlier papers have addressed floods from warm-air advection (WAA) in southeast Australia and around the globe, and extreme rainfall in US hurricanes and Australian tropical cyclones (TCs). This is the first paper to address the WAA phenomena in causing monsoon and TC floods and in TC-like systems which develop over the interior of northern Australia. The inland events help explain Australia’s worst tropical flooding disaster in 1916. A disastrous series of floods during late January and early February 2019 caused widespread damage in tropical north Queensland both in inland regions and along the coast. This occurred when some large-scale climate influences, including the sea surface temperatures suggested conditions would not lead to major flooding. Therefore, it is important to focus on the weather systems to understand the processes that resulted in the extreme rainfall responsible for the flooding. The structure of weather systems in most areas involved a pattern in which the winds turned in an anticyclonic sense as they ascended from the low to middle levels of the atmosphere (often referred to as WAA) which was maintained over large areas for 11 days. HYSPLIT air parcel trajectory observations were employed to confirm these ascent analyses. Examination of a period during which the heaviest rain was reported and compared with climatology showed a much stronger monsoon circulation, widespread WAA through tropical Queensland where normally its descending equivalent of cold-air advection is found, and higher mean sea level pressures along the south Queensland coast. The monsoon low was located between strong deep monsoon westerlies to the north and strong deep easterlies to the south which ensured its slow movement. This non-TC event produced heavy inland rainfall. Extreme inland rainfall is rare in this region. Dare et al. (2012), using data from 1969/70 to 2009/10, showed that over north Queensland non-TC events produced a large percentage of the total rainfall. The vertical structure associated with one of the earlier events that occurred in 2008 had sufficient data to detect strong and widespread WAA overlying an onshore moist tropical airstream. This appears to have played a crucial role in such extreme rainfall extending well inland and perhaps gives insight to the cause of a 1916 flooding disaster at Clermont which claimed around 70 lives. Several other events over the inland Tropics with strong WAA also help explain the 1916 disaster.

Severe weather systems can generate large waves and storm surges which can cause many fatalities in coastal areas. In extreme circumstances a single cyclone caused up to 500,000 fatalities in the Bay of Bengal in 1970. Adaption by authorities in that region from evacuations and construction of storm shelters have significantly reduced the number of such fatalities there. The effects of Hurricane Sandy in 2012 in New York City and surrounding areas is examined to show how ocean effects can cause many casualties. Scrutiny of a European storm shows how a slight error in analysis can fail to detect a deadly increase in intensity which caused many fatalities. World record wave height events are examined, and the historical Australian east coast events are investigated. The impacts from long period waves emanating from distant storms are shown to be a forecasting problem.

The Publisher regrets that this article is an accidental duplication of an article that has already been published in TCRR, Volume 8, Issue 2, June 2019, Pages 95–102, https://doi.org/10.1016/j.tcrr.2019.07.009. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Between 1883 and 1898, 24 intense tropical cyclones and extra tropical cyclones directly impacted on the southern Queensland and northern New South Wales coasts, with at least 200 fatalities in what was then a sparsely populated area. These events also caused record floods and rainfall, for example Brisbane City experienced its two largest ever floods over this period and Brisbane City set a 24-h rainfall record that still stands today. Additionally, a 24-h rainfall total of 907 mm occurred in a tributary of the upper Brisbane River resulting in a 15-m wall of water advancing down the river. Recent studies have shown that this part of Australia incurs the largest weather-related insurance losses. A major focus in this study is the seas these storms generated, leading to the loss of many marine craft and changes these waves brought to coastal areas. As a famous example of coastal erosion near Brisbane, the continual impacts from large waves caused a channel to form through Stradbroke Island to the open ocean forming two separate islands. Details of how this channel formed are described in relation to the storms. A climatology study of 239 Australian east coast storms that caused severe ocean damage between Brisbane and the Victorian border over the period between 1876 and February 2020 showed that 153 events occurred with a positive Southern Oscillation Index (SOI) trend and 86 events with a negative trend. The most active years were 1893 and 1967, both during positive SOI periods and both dominated by tropical cyclone activity. The 1893 events caused unparalleled floods and strongly contributed to the Jumpinpin breakthrough on Stradbroke Island, and the 1967 event was associated with historical Gold Coast beach erosion causing 9 billion normalised Australian dollars of insurance losses. The study also showed how direct tropical cyclone impacts in the study area decreased markedly following the June 1976 climate shift.

Hurricane Florence made landfall near Wrightsville Beach, North Carolina, around 1115 UTC 14 September as a weakening Category 1 hurricane (on the Saffir-Simpson Hurricane Wind Scale). Its slow movement through North and South Carolina resulted in extreme rainfall totals and major flooding making it the ninth-most-destructive hurricane to affect the United States. The structure of Florence is examined using microwave data, radiosonde observations and rainfall registrations to identify the processes along with its slow movement which caused the extreme rainfall. Two major processes were identified with initially, intense thunderstorms driven by strong buoyancy with some dynamic uplift, generated such rainfall while following landfall larger scale ascent with winds turned in an anticyclonic direction with height, appeared to be the principal cause of the heavy rainfall.

Hurricane Michael was intensifying as it made landfall devastating areas of the Florida Panhandle including the small town of Mexico Beach. The structure of the hurricane is examined using radar wind data made available from aircraft reconnaissance missions. This showed a dominant warm air advection configuration (winds turning in direction in an anticyclonic fashion with height) around the core of the hurricane. Conventional radiosonde data was also used to study the warm air advection environment east of a deep layered tough system which Michael moved into and which appeared to favour such strong intensification. The structure of this deep trough is also examined and compared with a situation where Hurricane Dennis in 2005 weakened as it approached the coast in much the same region. It appears that the thermal structure of the upper trough at low to middle levels is critical to whether the hurricane intensifies or weakens with the presence of strong cold air advection associated with weakening.

This research is the extension of a project studying the impact of 19th century severe weather events in Australia and their relation to similar events during the 20th and 21st century. Two floods with the worst known impacts in the Murray–Darling Basin (MDB) are studied. One of these events which occurred during 1956 is relativelywell known and the Bureau of Meteorology archives contain good rainfall data covering the period. Additionally, information on the weather systems causing this rainfall can be obtained. Rainfall, flood and weather system data for this event are presented here and compared with a devastating event during 1870. Although archived Australian rainfall data is negligible during 1870 and there is no record of weather systems affecting Australia during that year, a realistic history of the floods and weather systems in the MDB during 1870 is created. This follows an extensive search through newspaper archives contained in the National Library of Australia’s web site. Examples are presented showing how the meteorological data in 19th century newspapers can be used to create weather charts. Six such events in 1870 are demonstrated and three of these had a phenomenal effect on the Murray–Darling system. The 1870 floods followed drought type conditions and it is remarkable that it was worse in many ways than the 1956 event which followed flood conditions in the MDB during the previous year. The events in 1870 caused much loss of life from drowning in the MDB in particular froman east coast low (ECL) in April 1870 and two Victorian weather systems in September and October 1870. In 1956, there were also record-breaking events especially during March when all-time record monthly rainfall were reported in New South Wales. Overall the greatest impact from flooding across the whole MDB was associated with the 1870 flooding. Analyses of heavy rainfall areas in the MDB showed a linear trend increase from 1900 to 2018. Analysing the same data using an 8-year moving average highlighted three peaks around the five highest annual rainfall years. The largest peak occurred around 1950 and 1956, the second largest around 1973 and 1974 and the third around 2010. Each of these 5 years occurred during negative phases of the Interdecadal Pacific Oscillation (IPO) and positive phases of the Southern Oscillation Index (SOI). Studies have shown that the SOI is a climate driver in the MDB along with a persistent blocking high-pressure systems south of Australia along longitude 140°E with a low to its north. Three major blocking events with record rainfall and flooding in the MDB occurred in 1983, 1984 and 1990. Thiswas during the period 1977–1990 when blocking was conducive to heavy rain in the MDB and was coincidentwith a positive phase of the IPO, thus helping conflictwith the IPO–MDB heavy rainfall relationship. Persistent and unexplained middle level westerly winds kept subtropical Queensland clear of tropical cyclones during the negative phases of the IPO from 1999 to 2009 and during the 1960s, influencing low rainfall in the MDB during those periods.

Hurricanes Lane intensified in the Central Pacific with data from reconnaissance aircraft indicating it reached category 5 intensity on the Saffir-Simpson Hurricane Wind Scale while moving closer to Hawaii. The cyclone weakened as it moved closer to the Hawaiian Islands with its closest approach at 1500UTC 25 August 2018 when 175km south southwest of Honolulu with a central pressure of 995hPa. The impact on Hawaii was mainly record rainfall and the structure of this weather system is examined here to show how the winds turning anticyclonically with height in the lower to middle level troposphere play a crucial role in the intensification of Hurricane Lane to category 5 intensity and the generation of extreme rainfall.

Accurate thunderstorm warnings in the hours-to-minutes preceding impact are often limited by the complex evolution of the mesoscale atmospheric environment. To accurately capture these complexities, analysis of observations remained central to operational short-term nowcasting predictions of thunderstorms. Over the past 40 years, multiple highimpact thunderstorm events have impacted the Brisbane Metropolitan Area (BMA) of South East Queensland resulting in significant insured losses. Four of these high-impact events were the focus of the following work. These cases included three events that resulted in the greatest insured losses for the BMA, exceeding AU$4 billion (2017) (18 January 1985, 16 November 2008 and 27 November 2014) and a fourth significant event (24 December 1989). Synthesis of previous work indicates that the four high-impact cases occurred during a south-easterly change with strengthening winds ahead of the change, suggesting commonalities may exist that can be exploited for forecasting. This paper provides a detailed observational analysis of the environment and convective storms from the four BMA events to explore discriminating characteristics that may improve the skill of nowcasting. For the four BMA events, significant deep convection was observed along the change for the hours prior to the change’s arrival at the Brisbane Airport, potentially acting as an early indicator of favourable conditions for high-impact thunderstorms. It was found that the timing of the south-easterly change through Brisbane was also highly correlated for all events, occurring within a 90-min window during the mid-afternoon convective heating maximum. Despite the destructive severe weather, upper air conditions were marginal for supporting organised thunderstorms, highlighting the importance of capturing mesoscale processes, such as the south-easterly change. To further understand possible discriminators of the four high-impact BMA cases, a 10-year climatology of the mesoscale and synoptic environment associated with south-easterly change events was developed for the warm season months of November to January. It is shown that although only a small number of events are associated with high-impact BMA thunderstorms, these events share a set of conditions relating to the prechange wind shift, timing of the south-easterly change and radar signatures.

Tropical cyclone (TC) Oswald made landfall over north-east Australia as a minimal or Category 1 TC on the Australian scale on 21 January 2013. As it moved southward, it intensified over land and produced extreme rainfall for nearly 7 days. Tornadoes were reported and confirmed. Tragically, seven people died and insurance estimates were ~$1 billion. It is demonstrated that the event was associated with an interaction between the ex-Oswald circulation and an amplifying Rossby wave, which propagated north-eastward from high latitudes. Diagnoses showed that as the wave amplified and broke, a potential vorticity (PV) anomaly (PVA) extended to mid-levels, moved equatorward, merged with or axisymmetrised the ex-Oswald circulation through mid-levels. Backward trajectories from locations regularly scattered within the mid-level circulation illustrated that the storm transitioned from an isolated vortex into a circulation which was strongly influenced by its environment for at least 5 days. During this interaction, PV was advected from the environment towards the storm through mid-levels. The heavy rain coincided with the commencement and maintenance of this PV injection. The PV injection is quantified and shown to be consistent with PV advection by the mean radial flow. In addition, eddy angular momentum convergence in the mid- to upper levels coincided with an intensification of the circulation through this region. This was first related to outward transport of anticyclonic momentum by the asymmetric outflow at upper levels, followed by inward transport of cyclonic momentum by the asymmetric inflow. It is shown that the environmental interaction had an impact on vortex structure changes, rainfall and tornado development. We propose that the environmental processes influenced the ascent within the storm (1) via differential vorticity advection and baroclinic forcing, as the mid- to upper level PVA approached the circulation and (2) by low- to mid-level warm air advection.

Hurricanes Harvey and Irma had a huge impact on the Southern United States and in the case of Irma, also parts of the Caribbean Islands. Here we focus on the impact of both hurricanes following a period of rapid intensification. The structure of hurricanes were examined using wind data made available from aircraft reconnaissance missions. Intense convection developed in a region where the winds in the lower to middle levels turned anticyclonically with height. Earlier studies showed that this wind structure was similar to that would be found in an ascent region theoretically associated with Quasi-Geostrophic warm air advection.

One of the predictors used to forecast the rapid intensification of Tropical Cyclones (RI) is the symmetry of inner core convection which used infrared (IR) satellite imagery in the determination of this structure. This has led Forecasters and Researchers to conclude the symmetry of inner core convection was an important factor in RI. However we showed here using examples of RI that IR satellite imagery was not always a good guide to determine symmetry of inner core convection especially in the early stages of RI. However it has been previously shown that the heat released in these highly asymmetric convective bands may be transformed into the kinetic energy of the quasi-symmetric wind field and the available potential energy associated with the warm core. One of the most rapid RI cases had asymmetric inner core convection early in a six hour period where the Central Pressure dropped 29hPa and the sustained wind speed increased by 55knots(28.3ms(-1)). In other cases, where there was available inner core data, the inner core convection developed in a region where microwave imagery indicated asymmetric inner core convection. The convection was located where Dropsonde winds and Doppler radar winds from reconnaissance aircraft indicated a warm air advection pattern in that the winds turned anticy-clonically with height in the lowest 5km of the atmosphere. Updrafts from this strong convection near the eye become upward extending centres of cyclonic vorticity and may also produce warming in the eye with adjacent broad subsiding currents. It was shown that models could not forecast the RI of severe tropical cyclone Marcia as recently as February 2015. In this case convection was formed more vigorously on the western flank under the influence of a warm air advection wind pattern and convection remained mostly on this western side as RI proceeded. This process needs to be understood on its influence on the models failing to forecast RI. Rare Doppler wind of Hurricane Hermine showed the wind structure as a band a convection on the storm's eastern flank rapidly transformed into circular bands of convection as warm air advection winds increased around the inner core.