Australia in March 2018

In brief

  • Tropical cyclone Nora tracked through the Gulf of Carpentaria and western Cape York Peninsula coast to bring very heavy rain to northern Queensland
  • Tropical cyclone Marcus impacted Darwin on the 17th, the strongest tropical cyclone to impact Darwin since tropical cyclone Tracy in 1974 and the most intense in the Australian region in more than a decade
  • A strong cold change moved across the south from the 16th to the 18th, preceded by hot and windy conditions resulting in late-season fire weather over much of the southeast with total fire bans declared including across much of the New South Wales on the 18th
  • A very strong high pressure system moved south of Tasmania around the 22nd bringing very high pressures to some locations
  • Much of northeastern parts of Australia and Tasmania saw above average March rainfall.
  • Below average rainfall across most of the south, except Tasmania
  • Ninth warmest March on record and a warm month overall across most of the country excluding areas of Queensland which observed above average rainfall in March

Temperatures

March was warmer than average for much of Australia, with particularly warm days over New South Wales and Western Australia. For Australia as a whole it was the equal ninth warmest March on record, +0.97 °C above the long-term average. Maxima and minima were both above average, +1.18 °C and +0.76 °C respectively. March 2018 was not as warm as recent years, with March 2016 and 2017 being the warmest and third-warmest on record respectively.

For New South Wales as a whole, it was the seventh-warmest March on record, with a mean temperature that was 1.86 °C above average. Daytime temperatures were especially warm, the eighth warmest on record for New South Wales for March and more than 2 °C above average. It was the eighth warmest March on record for Western Australia, with very warm days, the seventh warmest on record for the State.

Maximum temperatures were above average across nearly all of southeastern Australia excluding Tasmania, which saw close to average temperatures. Large areas across inland New South Wales into southwestern Queensland saw daytime temperatures in the warmest 10% of historical observations (decile 10). Large parts of Western Australia also saw above average daytime temperatures, especially in the west of the State across a large region from around Geraldton up to Exmouth, which saw warmest on record March temperatures with anomalies peaking at around 3 to 4 degrees above the average. Above average rainfall led to cooler than average mean monthly maxima for northern parts of Queensland with some areas of very much below average (decile 1) daytime temperatures observed.

Minimum temperatures were above average across much of Queensland into northern New South Wales, southern parts of Victoria into southeastern South Australia and Tasmania, northern and eastern areas of the Northern Territory and much of the western part of Western Australia including the southern coastal regions. Nights were especially warm around Geraldton with warmest on record nights for March in this region. Nights were cooler than average across northern parts of Western Australia.

The month started warm over most of mainland Australia with warm anomalies extending from southern parts Queensland into New South Wales on subsequent days. Very cool daytime anomalies were observed across northern Queensland with a deep low pressure system bring rainfall to the region. Very cool daytime temperatures continued from the eighth to the middle of the month associated with an upper level trough which generated middle level cloud band which extended from central and southern Queensland, through the Northern Territory and into northern South Australia. Very warm daytime temperatures were seen across southern parts of Australia with a high pressure system located in the Tasman bringing onshore easterly flow to the region. Nighttime temperatures were relatively close to the average. The 17th saw very much above average temperatures across much of southeastern Australia ahead of a cold front. On the 18th temperatures in excess of 12 °C above average were observed along the New South Wales coast south of around Newcastle, with some March records set at exposed coastal sites from Point Perpendicular south to the Victorian border. These warm temperatures combined with the strong gusty winds ahead of the cold front resulted in severe fire danger ratings and total fire bans declared across much of the State. The month ended warm in the west of the country with late-season daytime temperature records set across Western Australia, including 45.9 °C at Roebourne on the 28th and Mardie on the 29th, the highest temperatures on record in Australia on any date after the equinox. Nights were cold in the east with a high pressure system resulting in clear skies with some stations across New South Wales and Victoria having their lowest March temperatures on record.


Areal average temperatures
Maximum Temperature Minimum Temperature Mean Temperature
Rank
(of 109)
Anomaly
(°C)
Comment Rank
(of 109)
Anomaly
(°C)
Comment Rank
(of 109)
Anomaly
(°C)
Comment
Australia 94 +1.18 95 +0.76 = 100 +0.97 equal 9th highest
Queensland 43 −0.14 100 +1.07 10th highest = 77 +0.47
New South Wales 102 +2.39 8th highest 97 +1.32 103 +1.86 7th highest
Victoria 95 +1.18 81 +0.34 = 84 +0.76
Tasmania = 70 +0.11 93 +0.69 = 83 +0.40
South Australia 92 +1.34 = 71 +0.42 81 +0.88
Western Australia 103 +1.67 7th highest; highest since 2005 = 93 +0.79 102 +1.23 8th highest
Northern Territory 77 +1.14 71 +0.29 75 +0.72

Rank ranges from 1 (lowest) to 109 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Anomaly is the departure from the long-term (1961–1990) average.


Temperature maps
MeanAnomalyDeciles
Mean
daily
maximum
temperatures
Map of mean daily maximum temperature Map of mean daily maximum temperature anomalies Map of mean daily maximum temperature deciles
Mean
daily
minimum
temperatures
Map of mean daily minimum temperature Map of mean daily minimum temperature anomalies Map of mean daily minimum temperature deciles
Mean
daily
temperatures
Map of mean daily temperature Map of mean daily temperature anomalies Map of mean daily temperature deciles

Rainfall

Rainfall for Australia as a whole was very close to average for March. However, there was large spatial variability across the country. Very much above average rainfall was observed across much of northern and eastern Queensland into southern parts of the Northern Territory and much of Tasmania. A small area centred on the Mid North Coast of New South Wales also saw above average rainfall. Below average rainfall was recorded across much of the rest of southern Australia, with some areas of very much below average, decile 1 (lowest 10%), rainfall.

The beginning of the month saw moderate rainfall totals over the Kimberley, Top End, and the north and central coasts of Queensland from a broad area of low pressure which extended across northern Australia. By the fifth of the month the low over Queensland had deepened, generating falls in excess of 100 mm in the northwest. A low pressure centre embedded on the surface trough deepened to the west of Townsville, with heavy rainfall accompanying the passage of the low as it slowly moved west. A surface trough extended southward through inland Queensland from a low pressure centre embedded over the southern Gulf of Carpentaria in the second week of the month resulting in several days of very heavy rainfall which affected the north tropical Queensland coast, causing major flooding.

Tropical cyclone Marcus formed in the Australian region on the 16th. Tropical Cyclone Marcus first crossed Darwin, and later the north Kimberley of Western Australia as a category 2 system before moving west away from the Western Australia coast towards the end of week. Marcus produced extensive shower and thunderstorm activity with moderate to heavy falls across the Top End and north Kimberley in Western Australia and then intensified to become the most intense tropical cyclone in the Australian region for more than a decade. From the 21st, a coastal trough off the Mid North Coast, with a strong high pressure system over the Tasman Sea feeding in humid, easterly winds, resulted in intense rainfall in the Hunter and Mid North Coast districts

From the 23rd of the month, tropical cyclone Nora developed over the Arafura Sea. Nora then tracked southeast towards the Gulf of Carpentaria and crossed the Cape York Peninsula in Queensland as a severe cyclone (category 3) and continued to travel south along the Gulf Country coast before moving inland and weakening to a tropical low. Severe tropical cyclone Nora and its remnants, and associated monsoon trough, produced moderate to heavy rainfall to the northern Top End and eastern parts of the Northern Territory, across the northern, western, central and east coast of Queensland, with very heavy falls and flooding recorded in the Cape York Peninsula coasts and Gulf Country.

Southern parts of mainland Australia were largely dry during March contributing to a dry start to the year for southeastern Australia. The January to March period was the driest first quarter of the year for New South Wales since 1986.


Area-average rainfall
Rank
(of 119)
Average
(mm)
Departure
from mean
Comment
Australia = 63 61.2 −0%
Queensland 106 152.1 +68%
New South Wales 42 31.0 −37%
Victoria 25 20.2 −51%
Tasmania 104 125.1 +39%
South Australia 41 6.3 −67%
Western Australia 33 19.9 −54%
Northern Territory 64 84.1 −14%
Murray-Darling Basin 38 22.8 −41%

Rank ranges from 1 (lowest) to 119 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Departure from mean is relative to the long-term (1961–1990) average.


Rainfall maps
TotalsPercentagesDeciles
Total
rainfall
Map of total rainfall Map of percentage of normal rain Map of rainfall deciles


Australian weather extremes during March 2018
Hottest day 45.9 °C    at Roebourne Aero (WA) on the 28th and Mardie (WA) on the 29th
Coldest day 1.4 °C    at Mount Hotham (Vic.) on the 26th
Coldest night −3.9 °C    at Butlers Gorge (Tas.) on the 21st
Warmest night 31.7 °C    at Wittenoom (WA) on the 28th
Wettest day 593.0 mm at Port Douglas - Warner St (Qld) on the 26th


Notes

The Monthly Climate Summary is prepared to list the main features of the weather in Australia using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

Climate Summaries are usually published on the first working day of each month.

This statement has been prepared based on information available at 1 pm EST on Monday 2 April 2018. Some checks have been made on the data, but it is possible that results will change as new information becomes available, especially for rainfall where much more data becomes available as returns are received from volunteers.

Long-term averages in this statement and associated tables are for the period 1961 to 1990 unless otherwise specified.

The system used for calculating areal averages of rainfall was changed in February 2009; the main effect was that current and historical values for Tasmania were increased. Since February 2012, ACORN-SAT has been used for calculating areal averages of temperature; the major change from earlier datasets is that the ACORN-SAT dataset commences in 1910, and hence rankings are calculated using a larger set of years.


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