Monthly Weather Review Northern Territory May 2012 Monthly Weather Review Northern Territory May 2012 The Monthly Weather Review - Northern Territory is produced twelve times each year by the Australian Bureau of Meteorology's Northern Territory Climate Services Centre. It is intended to provide a concise but informative overview of the temperatures, rainfall and significant weather events in Northern Territory 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 Northern Territory Climate Services Centre Bureau of Meteorology PO Box 40050 Casuarina NT 0811 AUSTRALIA By telephone (08) 8920 3813 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 Northern Territory 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 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 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 IDCKGC22R1. Prepared on 29 June 2012. ISSN 1836-392X Cover photograph Sunrise on a deck of altocumulus near Lilla Creek Station. Photograph by Gavin Heathertington-Tait, 2 May 2008. 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 Northern Territory May 2012 Overview • Rain eased in the north coast Significant weather • Dry season in Top End • Darwin Airport lowest maximum in 31 years Rain eased in the north coast A tropical low located over the Timor Sea with the Extremes in May 2012 associated rain band affected the north coast in the beginning of the month. However, the tropical low moved northwest as cool, dry southeast wind Hottest day affected the weather in the Territory for the rest of (Highest daily maximum temperature) May. 35.4 °C at Bradshaw on the 2nd Warmest days on average Dry season (Highest mean daily maximum temperature) The month of May marks the official beginning of the 32.7 °C at Middle Point AWS dry season. A series of high pressure cells in the Bight Coolest days on average directed cool, dry and windy southeast wind flow (Lowest mean daily maximum temperature) across most parts of the Territory throughout the 22.5 °C at Arltunga month. This southeasterly burst brought low Coldest day temperatures to the NT with a few records observed. (Lowest daily maximum temperature) 15.3 °C at Arltunga on the 24th Synoptic summary Coldest night (Lowest daily minimum temperature) The month started with a strong high pressure that −2.7 °C at Arltunga on the 17th moved into the Bight and directed cool, dry and Coolest nights on average gusty southeast winds. Showers and storms were (Lowest mean daily minimum temperature) contracted to the north coast and beyond ahead of 4.5 °C at Alice Springs Airport the surge. The cool and dry conditions persisted until Warmest nights on average the 6th, the pressure gradient eased over the (Highest mean daily minimum temperature) Territory, humidity and moisture conditions returned 25.2 °C at North East Island as the high moved east into the Tasman Sea. A weak Warmest night tropical low with associated rain band developed (Highest daily minimum temperature) over the Aarafura Sea and moved west into the 27.2 °C at North East Island on the 5th Timor Sea on the 7th. A weak trough developed over Warmest on average overall the western border and propagated east across the (Highest mean temperature) Territory ahead of another high developed of 27.7 °C at Cape Don Western Australia's west coast. Coolest on average overall A zonal easterly flow persisted across the Territory, (Lowest mean temperature) before another strong high pressure system moved 13.9 °C at Alice Springs Airport into the Bight on the 13th. A weak trough moved Wettest overall across the continent on the 17th, himidity and (Highest total rainfall) moisture returned untill the 23rd. Dry, cool and 189.0 mm at Gove Airport windy conditons again affected the Northern Wettest day Territory until the end of the month as an intense (Highest daily rainfall) high pressure system moved over the Bight on the 90.6 mm at McCluer Island on the 10th 26th. Highest wind gust 78 km/h at Cape Wessel on the 25th page 1 Monthly Weather Review Northern Territory May 2012 Daily mean sea level pressure analyses 1 May 2012 2 May 2012 3 May 2012 4 May 2012 5 May 2012 6 May 2012 7 May 2012 8 May 2012 9 May 2012 10 May 2012 11 May 2012 12 May 2012 13 May 2012 14 May 2012 15 May 2012 16 May 2012 17 May 2012 18 May 2012 page 2 Monthly Weather Review Northern Territory May 2012 19 May 2012 20 May 2012 21 May 2012 22 May 2012 23 May 2012 24 May 2012 25 May 2012 26 May 2012 27 May 2012 28 May 2012 29 May 2012 30 May 2012 31 May 2012 page 3 Monthly Weather Review Northern Territory May 2012 Temperatures New temperature records Record lowest May daily maximum temperature Years New record Old record of record Centre Island 20.6 on 25th 21.6 on 20th in 1981 38 Record lowest May mean maximum temperature Years New record Old record of record Jabiru Airport 32.1 = 32.1 in 1983 36 Record lowest May daily minimum temperature Years New record Old record of record Victoria River Downs 4.0 on 27th 4.5 on 30th in 2006 46 Yulara Aero 1.1 on 24th 1.3 on 24th in 1994 25 Record lowest May mean minimum temperature Years New record Old record of record Yulara Aero 6.0 6.5 in 1994 24 Lowest May mean minimum temperature for at least 20 years Years Observed this Most recent since month lower lower Alice Springs Airport 4.5 1.4 in 1976 36 Curtin Springs 5.8 3.7 in 1976 36 page 4 Monthly Weather Review Northern Territory May 2012 Maximum temperatures Anomalies of mean daily maximum temperature in May 2012 The month began with warm temperatures in the Top End. Several locations measured above 35 °C early on, and then gradually dropped through the month. On the 29th, Darwin Airport recorded a maximum of 24.8 °C, the lowest since 20 May 1981 when the maximum temperature was 22.7 °C. Gove airport measured the third coolest May on record with a monthly average maximum temperature of 28.7 °C, this is 1.2 °C below average. The record at Gove is 28.4 °C set in May of 2006. On the 2nd, Bradshaw recorded the hottest day of the month with 35.4 °C followed by Noonamah with 35.1 °C. There were three sites that recorded 35.0 °C; these were Oenepelli on the 1st and then Jabiru Airport and Katherine Country Club on the 2nd. The warmest days on average around the Territory were at Middle Point with 32.7 °C, followed by Noonamah with 32.3 °C, and then Bradshaw and Jabiru Airport both had 32.1 °C.