Western Australia June 2009 Monthly Weather Review Western Australia June 2009

Monthly Weather Review Western Australia June 2009 Monthly Weather Review Western Australia June 2009 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. 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 2009 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 IDCKGC11R1. Prepared on 27 July 2009. ISSN 1836-3032 Cover photograph Towering Cumulus clouds near Perth Airport. Photograph by Robert Lawry, 2 June 2009. 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 2009 Overview • Monthly rainfall near average. Extremes in June 2009 • Mean daily maximum near average. • Mean daily minimum near average. Hottest day June 2009 in Western Australia saw a series of strong (Highest daily maximum temperature) cold fronts cross southern parts of the state causing 36.0 °C at Warmun on the 30th above to very much above average rainfall near the Warmest days on average south coast, with several stations in the Southwest, (Highest mean daily maximum temperature) South Coastal and southern Great Southern 33.4 °C at Kalumburu experiencing their wettest June for more than Coolest days on average twenty years. Rainfall over the remainder of the (Lowest mean daily maximum temperature) state was mainly near average, and indeed when 14.4 °C at Rocky Gully averaged across the state as a whole, rainfall was Coldest day close to average. (Lowest daily maximum temperature) Much of the state experienced near average 8.8 °C at Shannon on the 29th maximum temperatures, apart from the Kimberley Coldest night which saw values above to very much above the (Lowest daily minimum temperature) long-term mean. A similar pattern existed with −2.8 °C at Southern Cross Airfield on the 22nd minimum temperatures as the area around Broome Coolest nights on average and to its southeast experienced mean overnight (Lowest mean daily minimum temperature) temperatures up to 3 °C warmer than the long-term 4.7 °C at Yeelirrie mean. The Gascoyne however, was a little cooler Warmest nights on average overnight than normal, with areas to 2 °C cooler than (Highest mean daily minimum temperature) normal around Carnarvon. Over the state as whole 24.2 °C at Troughton Island both the mean daily minimum and maximum 21.2 °C at Kuri Bay (WA mainland) temperatures were near average. Warmest night (Highest daily minimum temperature) 26.0 °C at Troughton Island on the 1st 23.8 °C at Kuri Bay (WA mainland) on the 2nd Wettest overall (Highest total rainfall) 417.5 mm at Northcliffe Wettest day (Highest daily rainfall) 78.2 mm at Woodridge Estate on the 19th Highest wind gust 124 km/h at Cape Naturaliste on the 29th page 1 Monthly Weather Review Western Australia June 2009 Significant weather 'mini-tornado that tossed trees around and ripped roofs off houses'. Tornadoes On the 19th, a cold front moved across the west The Perth Barrack St Jetty tide gauge recorded coast during the morning causing a tornado at 1.56 m during the morning of the 30th, which Bunbury and severe wind gusts at coastal sites. The equates to a storm surge of 0.63 m. One lane of the tornado passed south of the Bunbury city centre at Kwinana Freeway was closed during peak hour at approximately 1050 WST in the air mass following this time due to heavy spray from the adjacent Swan the front. SES reported four houses with roofs River. Gale force winds combined with heavy swell completely off, about seven others with major roof caused significant beach erosion along metropolitan damage and twenty others with minor roof damage. beaches during the 30th. Damage was confined to a west-southwest/ east-northeast discontinuous path about 30 metres wide and 3 kilometres long extending from the coast to the cemetery. The damage was consistent with an F1 tornado with wind speeds of 120−160 km/h at roof height. The front also caused severe wind gusts at the following sites: 111 km/h at Cape Leeuwin at 0130 WST; 115 km/h at Cape Naturaliste at 1021 WST; 96 km/h at Garden Island at 1050 WST and 93 km/h at Rottnest Island at 1109 WST. In the Perth metropolitan area, 33 SES callouts were reported. In Kalamunda, trees fell on a roof and powerlines; an Ocean Reef house sustained roof damage; whilst in Dardanup, a house sustained significant roof damage. On the 24th, a deep low near the Southwest district coast brought damaging winds to the Great Southern on the 24th. Damage consistent with the passage of a tornado was reported near Bokal at 1630 WST, then Katanning at about 1700 WST. At Bokal, trees were reported to have been ripped out of the ground and small hail fell associated with a thunderstorm. The damage path (oriented northwest to southeast) was estimated to be 100−130 metres wide and about 3 kilometres in length. Between Katanning and Kojonup, tree damage was reported as well as fences down, roofs ripped off houses and four silos were demolished. The damage path in this instance was estimated to be 3 to 4 kilometres in length and had a maximum width of about 100 metres. An eyewitness reported seeing the tornado, with the funnel cloud extending to the ground, after it had passed near the Kojonup-Katanning road and Marron Pool Road intersection. Strong Winds A series of strong cold fronts embedded within a vigorous westerly airstream affected the SWLD from the 26th to the 29th. Many potentially damaging gusts were recorded throughout the SWLD, particularly on the 29th. A storm spotter at Hyden in the Great Southern reported severe damage between 0830 and 0900 WST on the 29th, describing a 'mini-tornado' downing 50 tall salmon gum trees. The Countryman newspaper also reported damage near Lake King, also in the Great Southern, describing a page 2 Monthly Weather Review Western Australia June 2009 Synoptic summary through the SWLD on the 11th as the cloud band associated with the previous front over inland and The 1st June saw a ridge of high pressure over northern WA thickened. The systems brought eastern parts of WA, while a trough lay along the widespread rainfall to all but the northeast of WA, west coast. Showers and thunderstorms were with some heavy falls in the Pilbara, and reported in the Southwest Land Division (SWLD), thunderstorms observed in the SWLD and southern south Gascoyne and west Goldfields, whilst showers Goldfields.

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