Western Australia June 2012 Monthly Weather Review Western Australia June 2012

Monthly Weather Review Western Australia June 2012 Monthly Weather Review Western Australia June 2012 The Monthly Weather Review - Western Australia is produced twelve times each year by the Australian Bureau of Meteorology's Western Australia Climate Services Centre. It is intended to provide a concise but informative overview of the temperatures, rainfall and significant weather events in Western 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. Major discrepancies will be noted in later issues. We are keen to ensure that the Monthly Weather Review is appropriate to the needs of its readers. If you have any comments or suggestions, please do not hesitate to contact us: By mail Western Australia Climate Services Centre Bureau of Meteorology PO Box 1370 West Perth WA 6872 AUSTRALIA By telephone (08) 9263 2222 By email [email protected] You may also wish to visit the Bureau's home page, http://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 Western 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 all available years of record, which vary widely from site to site. They are not shown for sites with less than 30 years of record, as they cannot then be calculated reliably. Climatological extremes are generally taken from available observations from all available years of record. The number of years can vary substantially from site to site. Copyright © Commonwealth of Australia 2012 This work is copyright. You may download, display, print and reproduce this material in unaltered form only (retaining this notice) for your personal, non-commercial use or use within your organisation. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. Requests and inquiries concerning reproduction and rights should be addressed to Commonwealth Copyright Administration, Attorney General’s Department, Robert Garran Offices, National Circuit, Barton ACT 2600 or posted at http://www.ag.gov.au/cca. Product code IDCKGC21R1. Prepared on 17 September 2012. ISSN 1836-3032 Cover photograph Snow flurries just below the summit of Bluff Knoll (Stirling Ranges). Photograph by Peter Skeggs (Frederick Irwin Anglican School), 13 June 2012. Copyright © 2012, Peter Skeggs. Used with permission. If you have a photo you think would make a good cover for the Monthly Weather Review, please contact us at the address above. Monthly Weather Review Western Australia June 2012 Overview • Monthly rainfall near average Extremes in June 2012 • Mean daily maximum temperature near average • Mean daily minimum temperature near average Hottest day for WA; above average for southwest WA (Highest daily maximum temperature) Rainfall during June 2012 was near average for much 34.2 °C at Wyndham Aero on the 15th of Western Australia. Above to very much above Warmest days on average average rainfall was observed in isolated parts of (Highest mean daily maximum temperature) western, central, and southern WA, and a number of 30.7 °C at Kalumburu sites in the South Coastal district observed their Coolest days on average wettest June on record, partly due to a significant (Lowest mean daily maximum temperature) rainfall event early in the month. In what is typically 15.8 °C at Bickley a dry time of year in the north of WA, areas of above 15.8 °C at Katanning average rainfall were observed in small parts of the Coldest day Pilbara, particularly around Karratha, while large (Lowest daily maximum temperature) areas of below average rainfall were observed in the 10.6 °C at Katanning on the 13th Kimberley and central Interior. 10.6 °C at Mount Barker on the 13th Coldest night Above average maximum temperatures were (Lowest daily minimum temperature) observed in much of western, central and −4.0 °C at Eyre on the 15th southwestern WA during June, with below average Coolest nights on average daytime temperatures only observed in the east (Lowest mean daily minimum temperature) Kimberley. Averaged across the state as a whole, the 4.1 °C at Eyre mean maximum temperature for WA during June Warmest nights on average was close to average. Minimum temperatures were (Highest mean daily minimum temperature) below average in northern and eastern parts of WA, 21.9 °C at Troughton Island while western parts reported above to very much 15.5 °C at Onslow above average mean minima. Averaged across the Warmest night state as a whole, the June mean minimum (Highest daily minimum temperature) temperature was near average; however the Lower 24.7 °C at Troughton Island on the 3rd Southwest (southwest of a line from Jurien Bay to 22.3 °C at Port Hedland Airport on the 11th Bremer Bay) observed above average overnight Wettest overall temperatures. (Highest total rainfall) A series of low pressure systems and cold fronts 307.2 mm at Peppermint Grove crossed southwest WA from 7 to 13 June resulting in Wettest day significant damage in the region. Two tornadoes (Highest daily rainfall) were observed with one affecting inner northern 174.2 mm at Peppermint Grove on the 2nd Perth suburbs causing extensive localised damage. Highest wind gust Significant wind gusts that were some of the highest 146 km/h at Cape Naturaliste on the 10th on record for the region caused an unprecedented number of power outages to mainly western parts of the Southwest Land Division (SWLD), and unusually high sea levels as a result of storm surges caused localised coastal and estuarine inundation. page 1 Monthly Weather Review Western Australia June 2012 Significant weather Widespread property damage was reported in western parts of the SWLD with a significant number A series of low pressure systems and cold fronts of trees downed. Western Power reported that crossed southwest WA from 7 to 13 June resulting in unprecedented damage occurred to the electricity significant damage in the region. The following text supply grid southwest of a line from Geraldton to summarising the events is taken from Special Climate Ravensthorpe where the network of more than Statement 40, entitled "A significant winter wind and 90,000 kilometres of power lines was significantly storm surge event in southwest Western Australia in affected. More than 170,000 homes lost power after early June 2012" issued on 5 July 2012. The complete 800 power lines were brought down. It took several text is available at: http://www.bom.gov.au/climate/ days for power to be restored to all residents in the current/special-statements.shtml. region. Severe Thunderstorms Widespread rain was reported through western parts A trough off the west coast of the SWLD associated of WA as a result of the cloudband associated with with a quasi-stationary low to the southwest of the the low pressure system, and heavy falls were state gradually moved eastward over land during the reported in the southwest Gascoyne and northern morning of the 7th. Severe thunderstorms developed Central West districts. A number of locations on the trough and moved over the Lower West and registered daily totals in the 50 mm to 70 mm range, adjacent parts of neighbouring districts in the late with most of the rain occurring on the afternoon of morning and early afternoon, and a tornado was the 9th and morning of the 10th. A few sites broke reported in the Perth metropolitan area just after their highest June daily rainfall record as a result. A midday. Another tornado was reported near York in significant storm surge was reported along the SWLD the Central Wheat Belt at around 1230 WST. west coast on the 10th as sea levels up to approximately 0.8 m above the Highest Astronomical The tornado in Perth's north affected the suburbs of Tide (HAT) were recorded. Dianella and Morley, felling trees and power lines. The Fire and Emergency Services Authority (FESA) The WA Department of Transport Fremantle Fishing reported significant damage to approximately 20 Boat Harbour tide gauge recorded a maximum sea homes in Dianella, whilst businesses were also level of 2.12 m, 0.76 m above the HAT, and 0.14 m impacted with a video store in Morley having its roof above the previous highest sea level recorded by the damaged and windows broken by winds estimated gauge (1.98 m on 16 May 2003).

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