Monthly Weather Review South Australia January 2009 Monthly Weather Review South Australia January 2009 The Monthly Weather Review - South Australia is produced twelve times each year by the Australian Bureau of Meteorology's South Australian 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 Australian Regional Office South Australian Climate Services Centre Bureau of Meteorology 25 College Road KENT TOWN SA 5067 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. This version prepared on 12 March 2009, revising an issue prepared on 11 March 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 January 2009 Overview • Record lowest January rainfall experienced in Significant weather numerous locations. • Widespread heat wave conditions ended the Jamestown Thunderstorm month. On the 28th a thunderstorms occurred near • Highest ever maximum and minimum Jamestown in the Lower North district. It produced temperatures at several places. heavy rain causing local flooding nearby. Extremes in January 2009 Significant Fire Weather Days 13th January 2009 Hottest day Extreme fire weather conditions were recorded in 13 (Highest daily maximum temperature) districts. 48.2 °C at Kyancutta on the 28th Warmest days on average 20th January 2009 (Highest mean daily maximum temperature) Extreme fire weather conditions were recorded in 8 40.3 °C at Marree Comparison districts. Coolest days on average (Lowest mean daily maximum temperature) 22nd January 2009 23.1 °C at Neptune Island Extreme fire weather conditions were recorded in 10 Coldest day districts. (Lowest daily maximum temperature) 14.2 °C at Mount Lofty on the 2nd 27th January 2009 Coldest night Extreme fire weather conditions were recorded in 7 (Lowest daily minimum temperature) districts. 2.6 °C at Coonawarra on the 2nd Coolest nights on average 28th January 2009 (Lowest mean daily minimum temperature) Extreme fire weather conditions were recorded in 10 10.1 °C at Coonawarra districts. Warmest nights on average (Highest mean daily minimum temperature) 29th January 2009 25.1 °C at Moomba Airport Extreme fire weather conditions were recorded in 13 Warmest night districts. (Highest daily minimum temperature) 33.9 °C at Adelaide (Kent Town) on the 29th 30th January 2009 Wettest overall Extreme fire weather conditions were recorded in 7 (Highest total rainfall) districts. 31.5 mm at Innamincka (Dullingari) Driest overall (Lowest total rainfall) 0 mm at numerous locations Wettest day (Highest daily rainfall) 28.0 mm at Arkaroola on the 8th Highest wind gust 96 km/h at Cape Borda on the 31st page 1 Monthly Weather Review South Australia January 2009 Synoptic summary From the 20th to the 21st, the trough affected the centre and northeast of the State, with lower-level On Thursday 1st, a high to the southwest of the moisture favourable for isolated shower and Great Australian Bight extended a ridge thunderstorm activity in the northeast, extending to northeastwards across South Australia. Winds were the Flinders Ranges on the 21st. The passage of an moderate to fresh southwest to southeast with upper-air trough also produced isolated showers and isolated showers about the southern coast. During thunderstorms about the west coast. the 2nd and 3rd, the high centre progressed steadily eastwards to Bass Strait, bringing fine weather to During the 22nd, a weakening ridge along the west South Australia. coast and a redeveloping trough across the centre of the State permitted the equatorward extension of On the 4th, another ridge of high pressure extended the circulation around a complex area of low eastwards seawards of the Great Australian Bight. pressure centred to the southwest of Tasmania. A Weak troughs embedded within easterly flow, cold frontal passage and isolated showers affected together with lower-level moisture, brought isolated the southern coastal region, before linking to the thundery shower activity to the western border and inland trough and the attendant isolated shower and to the far northeast of the State. thunderstorm activity. Moderate northeast to From the 5th to the 7th, the ridge persisted across northwest winds became fresh to strong over the the Great Australian Bight, with isolated drizzle southeast of the State, ahead of a southwest to developing over the Lower South East. As another southeast change. high centre was building over the western Great On the 23rd, a weak ridge lay near the South Australian Bight during the 7th, the trough deepened Australian coastline, while a persistent trough and across the northeast of the State. In conjunction with lower-level moisture induced isolated afternoon lower-level moisture, this trough induced isolated shower and thunderstorm activity in the northeast. afternoon shower and thunderstorm activity in the An offshore cold front brought fresh northwesterly northeast, with the highest rainfall total during the flow to the southern coastal region. During the late six hours to 3 pm being 27 mm at Arkaroola. afternoon, this flow temporarily shifted From the 8th to the 12th, a weak ridge of high southwesterly in response to a deepening trough pressure predominated offshore of the State. A over Victoria. combination of lower-level moisture and a trough From the 24th to the 26th, a high centre built over induced isolated shower and thunderstorm activity the western Great Australian Bight, before slipping in the far northeast on the 11th. Early drizzle southeastwards towards Tasmania. At first, there occurred over the Lower South East on the 12th. were isolated showers over the southern agricultural On the 13th, a high centre became established over region. A trough and lower-level moisture produced the southern Tasman Sea while a trough progressed isolated showers and thunderstorms in the far eastwards across western and central South northeast. Australia. Moderate to fresh northeast to northwest By the 27th, the surface high centre had become winds brought well above average temperatures. At established over the southern Tasman Sea and was Port Lincoln Airport, the maximum temperature of directing a light to moderate northeast to northwest 44.7C was the warmest recorded at that locality airstream across South Australia. During the during the current month. A cooler and dry afternoon, a weak trough extended southeastwards southwest to southeast change raised isolated dust along the South Australian coastline. Lower-level in the west. moisture again brought isolated afternoon and During the 14th, the trough progressed across evening shower and thunderstorm activity to the eastern South Australia, but conditions remained northeast of the State. fine. On the 15th, a high centre built over the As a prelude to a developing heat wave event across western Great Australian Bight with isolated showers South Australia, other features of note during the occurring over the Lower South East.