Monthly Weather Review Australia October 2020 The Monthly Weather Review - Australia is produced by the Bureau of Meteorology to provide a concise but informative overview of the temperatures, rainfall and significant weather events in Australia for the month. To keep the Monthly Weather Review as timely as possible, much of the information is based on electronic reports. Although every effort is made to ensure the accuracy of these reports, the results can be considered only preliminary until complete quality control procedures have been carried out. Any major discrepancies will be noted in later issues. We are keen to ensure that the Monthly Weather Review is appropriate to its readers' needs. If you have any comments or suggestions, please contact us: Bureau of Meteorology GPO Box 1289 Melbourne VIC 3001 Australia [email protected] www.bom.gov.au Units of measurement Except where noted, temperature is given in degrees Celsius (°C), rainfall in millimetres (mm), and wind speed in kilometres per hour (km/h). Observation times and periods Each station in Australia makes its main observation for the day at 9 am local time. At this time, the precipitation over the past 24 hours is determined, and maximum and minimum thermometers are also read and reset. In this publication, the following conventions are used for assigning dates to the observations made: Maximum temperatures are for the 24 hours from 9 am on the date mentioned. They normally occur in the afternoon of that day. Minimum temperatures are for the 24 hours to 9 am on the date mentioned. They normally occur in the early morning of that day. Mean temperatures are the average of the daily maximum and daily minimum temperatures. Daily rainfall is for the 24 hours to 9 am on the date mentioned. This means a significant fraction of the rain may have occurred on the previous calendar day. Monthly rainfall is for the period from 9 am on the last day of the previous month to 9 am on the last day of this month. Maximum daily wind gusts are in the 24 hours from midnight to midnight. Climatological values The climatological averages shown in the text and tables are generally long-term means based on observations from the years 1961–1990. They are not shown for sites with less than 25 years of record in that time, as they cannot then be calculated reliably. Climatological extremes are generally taken from all available years of record; the number of years can vary markedly from site to site. Records The tables of records are not exhaustive, as they only show sites with at least 30 years of record. This may exclude locations where a new site has been established; this means even some major cities and towns may not be listed. Maps The temperature and rainfall maps are intended to give an overview of the country. There could be discrepancies between the values shown on these maps and those at individual locations, as a result of the way the maps are generated. A wide range of maps of rainfall, temperature and other variables, covering the whole country and smaller regions can be found at www.bom.gov.au/climate/maps. Accessing data Tables of daily values for selected sites are included toward the back of the Monthly Weather Review. Data from many more sites and for other times are available from www.bom.gov.au/climate/data/. Copyright © Commonwealth of Australia 2020 This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced without prior written permission from the Bureau of Meteorology. Requests and enquiries concerning reproduction and rights should be addressed to: Publishing Unit, Bureau of Meteorology, GPO Box 1289, Melbourne VIC 3001 Product code IDCKGC17R1. Prepared on 25 November 2020 Cover photograph Virga falling from altocumulus over canola fields at Bridgewater in north-western Victoria. Photograph by Andrew Chapman, 20 September 2008. Copyright © 2008 Andrew Chapman. Used with permission. Overview • The national mean temperature was a degree minimum temperature was the third-highest on above the October average. record. • The national mean maximum temperature was • Mean minimum temperatures were above to very warmer than average. much above average across much of Australia • Mean maximum temperatures were warmer than apart from the central and north-west mainland. average for most of the west, northern tropics, and • Rainfall was above average for Australia overall, east of the mainland. and South Australia was the ninth-wettest October • The national mean minimum temperature was on record, despite below to very much below much warmer than average; Victoria mean average rainfall in south-west Western Australia. Areal averages in October 2020 Rainfall anomaly Mean maximum Mean minimum Mean temperature temperature anomaly temperature anomaly anomaly Australia +35% +0.92 °C +1.18 °C +1.05 °C Western Australia −23% +1.46 °C +0.97 °C +1.22 °C Northern Territory +96% +0.34 °C +1.24 °C +0.79 °C South Australia +119% +0.04 °C +1.15 °C +0.59 °C 9th-highest Queensland +6% +1.00 °C +1.28 °C +1.14 °C New South Wales +35% +1.28 °C +1.46 °C +1.37 °C Victoria +34% +0.60 °C +1.62 °C +1.11 °C 3rd-highest Tasmania +23% −0.25 °C +0.42 °C +0.08 °C 1 Monthly Weather Review - Australia - October 2020 Extremes in October 2020 Hottest day Coldest night Wettest day Warmest overall Coolest overall Wettest overall Strongest wind gust Australia 43.6 °C −5.5 °C 209.8 mm 32.9 °C 3.2 °C 391.6 mm 139 km/h at Roebourne Aero at kunanyi (Mount at Smiths Lake at Wyndham Aero at kunanyi (Mount at Falls Creek at Thredbo AWS (WA) on the 14th Wellington (Patsys Flat Road) (WA) Wellington (Rocky Valley) (Vic.) (NSW) on the 8th Pinnacle) (Tas.) on (NSW) on the 27th Pinnacle) (Tas.) the 25th Western 43.6 °C −2.2 °C 43.6 mm 32.9 °C 14.2 °C 94.6 mm 87 km/h Australia at Roebourne Aero at Salmon Gums at El Questro on the at Wyndham Aero at Shannon at Kununurra Aero at Giles on the 14th Res.Stn. on the 6th 8th Meteorological Office on the 18th Northern 42.4 °C 5.3 °C 177.0 mm 32.4 °C 21.4 °C 274.0 mm 98 km/h Territory at Ngukurr Airport at Yulara Airport on at Marrara on the at Bradshaw and at Arltunga at Karama at McArthur River on the 21st the 7th 8th Bradshaw - Mine Airport on Angallari Valley the 25th (Defence) South 40.8 °C −0.1 °C 77.0 mm 22.5 °C 12.4 °C 147.2 mm 124 km/h Australia at Oodnadatta at Keith (Munkora) at Quorn on the at Oodnadatta at Mount Lofty at Quorn at Woomera Airport on the 22nd on the 20th 24th Airport Aerodrome on the 22nd Queensland 42.8 °C 2.3 °C 89.0 mm 30.3 °C 16.6 °C 182.8 mm 122 km/h at Julia Creek at Stanthorpe Leslie at Theodore on the at Normanton at Applethorpe at Brisbane at Roma Airport Airport on the 22nd Parade on the 10th 26th Airport on the 22nd New South 38.0 °C −4.1 °C 209.8 mm 22.4 °C 5.5 °C 369.8 mm 139 km/h Wales at Walgett (Brewon at Thredbo AWS on at Smiths Lake at Mungindi Post at Thredbo AWS at Thredbo AWS at Thredbo AWS AWS) on the 17th the 25th (Patsys Flat Road) Office on the 8th on the 27th Victoria 37.1 °C −5.2 °C 73.6 mm 17.8 °C 5.5 °C 391.6 mm 128 km/h at Walpeup at Mount Hotham at Falls Creek on at Mildura Airport at Mount Hotham at Falls Creek at Mount Hotham Research on the 4th on the 25th the 17th (Rocky Valley) on the 8th Tasmania 28.2 °C −5.5 °C 140.0 mm 13.5 °C 3.2 °C 306.6 mm 130 km/h at Flinders Island at kunanyi (Mount at Gray (Dalmayne at Flinders Island at kunanyi (Mount at Lake Margaret at kunanyi (Mount Airport on the 3rd Wellington Rd) on the 9th Airport Wellington Dam Wellington Pinnacle) on the Pinnacle) Pinnacle) on the 25th 2nd In this table Hottest day is the highest daily maximum temperature, Coldest night is the lowest daily minimum temperature, Wettest day is the highest daily rainfall total, Warmest overall is the highest mean monthly temperature, Coolest overall is the lowest mean monthly temperature and Wettest overall is the highest total monthly precipitation. 2 Monthly Weather Review - Australia - October 2020 Significant weather Queensland diameter at Springfield, 7 cm in diameter around Gatton, and 5 cm in diameter at Seventeen Mile. Severe thunderstorms across south-east Queensland New South Wales Widespread thunderstorms affected central and Heavy rain and severe thunderstorms south-east Queensland between the 24th and 29th. A succession of troughs and low pressure systems Thunderstorms affected Brisbane on the 24th and along the coast brought heavy rain and severe storms 25th, then the 27th and 28th, bringing heavy rainfall to late in the month. some sites, flash-flooding, and strong wind gusts. Severe storms were reported in a wide area of Thunderstorms produced large hail, with reports up to eastern New South Wales on the 23rd and 24th, with 6 cm hail in diameter south of Gayndah, fallen power a number of sites reporting 2-day totals of 60 to lines in the Caboolture area, and localised flash- 70 mm.