Monthly Weather Review South Australia June 2009 Monthly Weather Review South Australia June 2009 The Monthly Weather Review - South Australia is produced twelve times each year by the Australian Bureau of Meteorology's South Australia Climate Services Centre. It is intended to provide a concise but informative overview of the temperatures, rainfall and significant weather events in South 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 South Australia Climate Services Centre Bureau of Meteorology PO Box 421 Kent Town SA 5071 AUSTRALIA By telephone (08) 8366 2600 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 South 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 20 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 IDCKGC23R1. Prepared on 28 July 2009. ISSN 1836-3024 Cover photograph Wave clouds over the Adelaide Hills. Photograph by Bob Schahinger, 30 November 2002. 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 South Australia June 2009 Overview • Good rainfall over most of the agricultural districts. • Warmer than average temperatures over the state. • Gale force gusty winds on the 30th during passage of a cold front. Extremes in June 2009 Hottest day (Highest daily maximum temperature) 30.5 °C at Moomba Airport on the 30th Warmest days on average (Highest mean daily maximum temperature) 21.0 °C at Marree Comparison Coolest days on average (Lowest mean daily maximum temperature) 10.7 °C at Mount Lofty Coldest day (Lowest daily maximum temperature) 7.9 °C at Mount Lofty on the 23rd Coldest night (Lowest daily minimum temperature) −2.6 °C at Gluepot Reserve (Gluepot) on the 11th Coolest nights on average (Lowest mean daily minimum temperature) 4.6 °C at Yongala Warmest nights on average (Highest mean daily minimum temperature) 12.8 °C at Neptune Island Warmest night (Highest daily minimum temperature) 18.4 °C at Coober Pedy Airport on the 30th Wettest overall (Highest total rainfall) 219.0 mm at Rocky River (Brookland Park) Driest overall (Lowest total rainfall) 0 mm at Innamincka (Dullingari) 0 mm at Marree (Etadunna) Wettest day (Highest daily rainfall) 85.2 mm at Rocky River (Brookland Park) on the 30th Highest wind gust 115 km/h at Whyalla Aero on the 30th page 1 Monthly Weather Review South Australia June 2009 Significant weather gusts of 90−95 km/h were recorded at Coles Point (Lower Eyre Peninsula) and Stenhouse Bay (Yorke Gulf St Vincent Waterspouts Peninsula). During the early afternoon of 6 June, a cluster of cumulus clouds spawned a series of waterspouts over Gulf St Vincent, which were clearly visible from Yorke Peninsula and Adelaide beaches. Severe Thunderstorms 13 June 2009 A late afternoon thunderstorm on 13 June produced a tornado, which caused a narrow 1.5 km long swathe of tree and shed damage near Kingston in the Upper South East. Damage rated at F0. 23 June 2009 During the evening of 23 June, severe winds associated with a convective cell caused significant structural damage to a large, not yet completed machinery shed near Arthurton on Yorke Peninsula. Winds may have been from a downburst or a tornado. Concrete footings were lifted 20−30 cm out of the ground, indicating considerable vertical forcing, which would suggest a tornado. 30 June 2009 A severe thunderstorm on a strong cold front tracked across Adelaide suburbs on 30 June. Winds with the storm tipped over a semi-trailer and brought down power poles at West Beach. A wind gust to 106 km/h occurred at Adelaide Airport. The same storm caused significant tree damage in Flagstaff Hill and Happy Valley. Later the same day, a thunderstorm in the unstable post frontal air-stream generated a wind gust to 107 km/h at Coles Point on Lower Eyre Peninsula. This day also listed under Severe Winds. Severe Winds 30 June 2009 A strong front linked to a large, deep low pressure system swept across South Australia on 30 June. Severe winds were experienced in all but the Upper and Lower South East districts, with most of the damage occurring with or shortly following the front. In the Pastoral districts, blowing dust accompanied the front. Emergency services responded to about 1000 call-outs and about 30,000 customers lost power. Parts of Adelaide were amongst the worst affected areas with a lot of tree related damage. Several houses also suffered roof damage. Some of the higher wind gusts recorded were 115 km/h at Whyalla (Eastern Eyre Peninsula), 113 km/h at Nuriootpa (Mount Lofty Ranges) and Loxton (Riverland) and 106 km/h at Adelaide Airport. Refer also to Severe Thunderstorm section above. A second period of severe wind gusts affected southern districts during the evening of 30 June as the main upper cold trough moved through. Wind page 2 Monthly Weather Review South Australia June 2009 Synoptic summary agricultural region. With the high centre contracting eastwards across New South Wales during the 11th From Monday 1st until Wednesday 3rd, a strong high and the 12th, there was a brief fine spell across centre over the southern Tasman Sea extended a South Australia. With the poleward building of ridge northwestwards towards the Head of the Bight, another ridge of high pressure well southwards from continuing into the interior of South Australia. This Western Australia, a low pressure system separated ridge cradled a trough that was embedded within from westerly flow. As this low developed through a easterly flow near the eastern border of the State. deep layer and approached the southwestern Great The trough was the surface reflection of an upper-air Australian Bight on the 12th, a cloud band brought trough that was orientated from the southwest to isolated shower activity to the southern half of the the northeast across eastern South Australia. During State. Winds strengthened near the coast, with Cape the 1st, cool daytime temperatures accompanied Willoughby recording a 91 km/h northerly wind gust rain areas in the north of the State. Rain areas were at 4.40 pm. more persistent across most of the agricultural region, tending to showers further westwards. From the 13th until the 15th, a building high centre During the six hours to 3 pm on the 2nd, along the well to the south of the continent steered a filling windward side of the Mount Lofty Ranges, low centre east-northeastwards from the eastern Strathalbyn recorded 10 mm of rainfall. Great Australian Bight, passing across southern Spencer Gulf, Yorke Peninsula, and the Mid-North on Meanwhile, a high centre to the southwest of Perth the 14th, and continuing into southern New South extended a ridge southeastwards, with a discrete Wales on the 15th. Shower activity occurred across high centre of 1033 hPa building unusually far most the agricultural region, including isolated polewards near 54S 132E on the 4th. A ridge over thunderstorms on the 13th. During the six hours to northeastern South Australia linked to a weakening 3 pm, there was 10 mm at Cape Borda on the 13th, high centre over the Tasman Sea.