Monthly Weather Review Victoria January 2009 Monthly Weather Review Victoria January 2009
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Monthly Weather Review Victoria January 2009 Monthly Weather Review Victoria January 2009 The Monthly Weather Review - Victoria is produced twelve times each year by the Australian Bureau of Meteorology's Victoria Climate Services Centre. It is intended to provide a concise but informative overview of the temperatures, rainfall and significant weather events in Victoria 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 Victoria Climate Services Centre Bureau of Meteorology PO Box 1636 Melbourne VIC 3001 AUSTRALIA By telephone (03) 9669 4956 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 Victoria 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 10 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 IDCKGC27R1. This version prepared on 12 March 2009, revising an issue prepared on 24 February 2009. ISSN 1836-3016 Cover photograph A pyrocumulus cloud rises above smoke from a bushfire near Boolarra. Photograph by Lisa Parkinson, 30 January 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 Victoria January 2009 Overview Victoria endured a series of record extremes during Significant weather January: Cold front brings winds and thunderstorms • record-breaking cold start to the month On the 22nd, a cold front and associated low • record-breaking heatwave to end the month pressure trough moved through central districts • record-breaking low rainfall during the afternoon and evening before weakening Extremes in January 2009 over the northeast at night. Severe thunderstorms developed over the eastern half of the state associated with the low pressure trough. There were Hottest day (Highest daily maximum temperature) reports of thunderstorm-related damage in 45.8 °C at Avalon Airport on the 29th Healesville, Rushworth, Mansfield and Orbost and at Charlton on the 31st through the afternoon, along with numerous wind gusts in excess of 100 km/h, the highest being a Warmest days on average (Highest mean daily maximum temperature) 118 km/h gust at Mount Hotham around 10:30 am. 35.5 °C at Ouyen (Post Office) Gusty winds continued in alpine areas through the morning of the 23rd. Coolest days on average (Lowest mean daily maximum temperature) Heat wave 18.2 °C at Mount Hotham A heat wave affected Victoria (along with other parts Coldest day of southeastern Australia) from the 27th until the end (Lowest daily maximum temperature) of the month. In much of central, southern and 3.5 °C at Mount Baw Baw on the 16th western Victoria, maximum temperatures widely Coldest night reached their highest levels since at least 1939. (Lowest daily minimum temperature) Melbourne narrowly missed its all-time temperature −3.7 °C at Dinner Plain (Mount Hotham Airport) record on the 30th, with 45.1 °C the second-highest and Mount Hotham on the 2nd on record behind 45.6 °C on 13 January 1939. In Coolest nights on average Geelong (45.3 °C on the 29th) and Wilsons (Lowest mean daily minimum temperature) Promontory (41.4 °C on the 30th) even the 8.4 °C at Mount Hotham 1939 marks were surpassed. Other stations where Warmest nights on average all-time records were set or equalled included (Highest mean daily minimum temperature) Mangalore Airport, Maryborough, Tatura, Scoresby, 17.0 °C at Mildura Airport Jeywodd, Lake Eildon, Wonthaggi, Moorabbin and Warmest night Dartmouth. (Highest daily minimum temperature) 30.5 °C at Melbourne Airport on the 29th Overnight minimum temperatures were also very Wettest overall high in many places. Melbourne Airport’s minimum (Highest total rainfall) of 30.5 °C on the 29th was only 0.4 °C short of the 77.2 mm at Falls Creek (Rocky Valley) Victorian record, set at Mildura in 1999 and Kerang in Driest overall 2001. The extremely high day and night temperatures (Lowest total rainfall) combined for a record high daily mean temperature 0 mm at numerous sites in northwestern and at Melbourne on the 29th (35.0 °C), which was then central districts exceeded on the 30th (35.4 °C). Wettest day Over the five days 27−31 January 2009, maximum (Highest daily rainfall) temperatures were 12−15 °C above normal over 48.4 mm at Dartmouth Reservoir on the 23rd much of Victoria. Melbourne endured three Highest wind gust successive days (28th, 29th and 30th) of 119 km/h at Mount Hotham on the 22nd temperatures above 43 °C for the first time in recorded history. The heatwave continued into early February, and a Special Climate Statement has been prepared. page 1 Monthly Weather Review Victoria January 2009 Synoptic summary Synoptic patterns during January were characterised by enhanced westerlies, most unusual for a summer month, and this was associated with a number of cold fronts associated with strong and hot northwest winds preceding their arrival. The enhanced westerlies prevented incursions of cooler air over the continent, which steadily heated up over the second half of the month. A marked cold front crossed on the 22nd, bringing strong winds and some thunderstorms. Perhaps the most important synoptic feature during the month, and the one responsible for Victoria's heatwave, was a blocking high pressure system in the Tasman Sea which developed from about the 26th. The system directed a northerly air flow over the southeast of Australia, moving an extremely hot air mass over the southeast of the continent. page 2 Monthly Weather Review Victoria January 2009 Daily mean sea level pressure analyses 1 January 2009 2 January 2009 3 January 2009 4 January 2009 5 January 2009 6 January 2009 7 January 2009 8 January 2009 9 January 2009 10 January 2009 11 January 2009 12 January 2009 13 January 2009 14 January 2009 15 January 2009 16 January 2009 17 January 2009 18 January 2009 page 3 Monthly Weather Review Victoria January 2009 19 January 2009 20 January 2009 21 January 2009 22 January 2009 23 January 2009 24 January 2009 25 January 2009 26 January 2009 27 January 2009 28 January 2009 29 January 2009 30 January 2009 31 January 2009 page 4 Monthly Weather Review Victoria January 2009 Temperatures Very low temperatures early in the month Highest January mean maximum temperature for at least contrasted against very high temperatures in the 20 years Observed Years final week. The mean temperature for Victoria in this Most recent since January 2009 was 20.1 °C, which is 1.21 °C above the month higher higher long-term average. Omeo Comparison 29.3 29.9 in 1932 76 Maryborough 32.1 32.6 in 1969 40 Echuca Aerodrome 34.7 35.1 in 1981 28 New temperature records Tatura Inst Sustainable Ag 32.8 32.9 in 1981 28 Ballarat Aerodrome 28.5 29.1 in 1981 27 Record highest January daily maximum temperature Years Castlemaine Prison 31.0 31.5 in 1981 23 New record Old record of East Sale Airport 27.9 28.5 in 1988 21 record Mangalore Airport 33.2 33.4 in 1988 21 Wilsons Promontory on the 18th 41.4 on the 29th 41.1 53 Lighthouse in 1959 Record lowest January daily