The dynamics of slow‐moving coherent cyclonic potential vorticity anomalies and their links to heavy rainfall over the eastern seaboard of Australia

Barnes, Michael A.; King, Malcolm J.; Reeder, Michael J.; Jakob, Christian

doi:10.1002/qj.4503

Cited by 10 publications

(2 citation statements)

References 48 publications

(88 reference statements)

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“…More detailed reviews of Lagrangian tracking methods are presented by Barnes, et al [22], Zhan and Chen [23], and Messmer and Simmonds [24], who also analyse compound precipitation and wind extreme events induced by cyclones.…”

Section: Storm Tracks Determined By Tracking Methodsmentioning

confidence: 99%

Seasonal Cycle of Southern Hemisphere Explosive Growth and Decay of Storms

Osbrough,

Frederiksen

2024

Atmosphere

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The seasonal variability of Southern Hemisphere (SH) synoptic-scale weather systems is analysed for the 20-year timespan 1997 to 2016. The relationships between the SH jet streams and storm tracks based on lower tropospheric circulation anomalies filtered into the high-pass (periods < 4 days) and band-pass (periods between 4 and 8 days) types are examined based on 6-hourly reanalysis data. Leading Empirical Orthogonal Functions (EOFs) and storm tracks based on all (growing and decaying) disturbances are determined. As well, the structure and standard deviations of streamfunction fluctuations are determined separately in three growth rate and three decay rate bins focusing on explosive growth and decay. In all cases, and in each season, the band-pass storm tracks are more zonally symmetric than the high-pass standard deviations and this is also reflected by the EOFs. Leading EOFs in both bands are monopole wavetrains of highs and lows located in the storm tracks with some band-pass disturbances having dipole structures consistent with blocking and northwest cloud bands. EOFs based on the bin with slow-growing fluctuations are structurally similar to the standard EOFs based on all disturbances. EOFs for moderately and explosively growing disturbances are increasingly displaced equatorward with a larger growth rate.

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Section: Storm Tracks Determined By Tracking Methodsmentioning

confidence: 99%

Seasonal Cycle of Southern Hemisphere Explosive Growth and Decay of Storms

Osbrough,

Frederiksen

2024

Atmosphere

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“…Coherent PV anomalies are tracked on the 315 K surface for the extended summer season (November-March) over the years 1980-2020 using a similar methodology to Barnes et al (2023); Berry et al (2012); Hoang et al (2017), which is briefly described here. In this study, we multiply the relative and PV by −1 so that positive values are cyclonic in the Southern Hemisphere.…”

Section: Tracking Algorithmsmentioning

confidence: 99%

The meteorology of the 2019 North Queensland floods

Robinson,

Barnes,

Narsey

et al. 2024

Quart J Royal Meteoro Soc

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In January–February 2019, a monsoon low developed over northeastern Australia and brought extreme flooding to much of tropical Queensland. The European Centre for Medium Range Weather Forecasts reanalyses are used to explain the formation and severity of the event. Strong anticyclonic Rossby wave breaking to the southeast of Australia produced weak steering winds over northern Australia, and consequently the low remained nearly stationary for over a week, contributing to the extreme rainfall. Furthermore, the tropical moist margin was deformed by a series of disturbances along the monsoon trough, which drew moist maritime air over land. The event examined has much in common with the composite mean of slow‐moving potential vorticity anomalies in North Queensland, including weak background winds and heavy precipitation. An ensemble subseasonal forecast with the Australian Bureau of Meteorology's Australian Community Climate and Earth System Simulator Seasonal prediction version system 1 shows the same relationship between the background flow, the steering, and the subsequent rainfall. Hence, accurately forecasting the background winds is a prerequisite to forecasting such extreme rainfall.

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Atmospheric water vapour transport in ACCESS‐S2 and the potential for enhancing skill of subseasonal forecasts of precipitation

Reid,

Hudson,

King

et al. 2023

Quart J Royal Meteoro Soc

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Extended warning of above average and extreme precipitation is valuable to a wide range of stakeholders. However, the sporadic nature of precipitation makes it difficult to forecast skilfully beyond one week. Subseasonal forecasting is a growing area of science that aims to predict average weather conditions multiple weeks in advance using dynamical models. Building on recent work in this area, we test the hypothesis that using large‐scale horizontal moisture transport as a predictor for precipitation may increase the forecast skill of the above median and high precipitation weeks on subseasonal timescales. We analysed retrospective forecast (hindcast) sets from the Australian Bureau of Meteorology's latest operational subseasonal‐to‐seasonal forecasting model, ACCESS‐S2, to compare the forecast skill of precipitation using integrated water vapour transport (IVT) as a proxy, compared to using precipitation forecasts directly. We show that ACCESS‐S2 precipitation generally produces more skilful forecasts, except over some regions where IVT could be a useful additional diagnostic for warning of heavy precipitation events.This article is protected by copyright. All rights reserved.

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The dynamics of slow‐moving coherent cyclonic potential vorticity anomalies and their links to heavy rainfall over the eastern seaboard of Australia

Cited by 10 publications

References 48 publications

Seasonal Cycle of Southern Hemisphere Explosive Growth and Decay of Storms

Seasonal Cycle of Southern Hemisphere Explosive Growth and Decay of Storms

The meteorology of the 2019 North Queensland floods

Atmospheric water vapour transport in ACCESS‐S2 and the potential for enhancing skill of subseasonal forecasts of precipitation

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