Australia in April 2010

In Brief

April was significantly warmer than normal over most of Australia, especially at night. Overnight minimum temperatures for Australia were the second-highest on record for April, and ranked in the top three in four states. Maximum temperatures were less extreme but were still well above normal. Rainfall was also above normal over much of the country, particularly in the interior, although it was near or below normal in many southern areas.


Temperatures

Maximum temperatures were 0.93C above normal (10th highest on record). The most significant warmth was in Western Australia, which was fifth-warmest on record. Daytime temperatures were at least 1C above normal over most of the state except the north Kimberley and the western coastal strip, and were 2C or more above normal over most inland, with anomalies reaching +4C around Warburton. Records were set locally in the inland Pilbara. Anomalies exceeding 1C extended into the southwestern Northern Territory and northwestern South Australia. Another area which was at least 1C above normal was in the coastal southwest, encompassing all of Tasmania, and the eastern coastal strip between Geelong and the NSW-Queensland border.

The most significant area with below-normal maximum temperatures was a region centred on the Gulf region of northwestern Queensland and the eastern Northern Territory, with temperatures more than 1C below normal along the Gulf of Carpentaria coast in both the NT and Queensland. Elsewhere, only a few patches had daytime temperatures slightly below normal, including areas around Mount Gambier, exposed WA coastal areas around Carnarvon and Geraldton, and some areas along the inland NSW/Queensland border.

Overnight minimum temperatures were 1.68C above normal, the second-highest on record (ranking only behind 2005). Western Australia ranked second, and South Australia, Tasmania and Victoria all third. They were above normal almost throughout the country, the only exceptions being the far southwest of Western Australia and coastal parts of that states Gascoyne region. Most areas were at least 1C above normal, except for western WA (west of a Port Hedland-Kalgoorlie-Esperance line) and the eastern half of NSW.

The strongest anomalies, more than 2C above normal, occurred in the eastern half of Western Australia, most of the Northern Territory outside the Top End, northern South Australia, northwestern Victoria, and central and western Victoria. Anomalies exceeded +4C around Warburton (WA), and east of Alice Springs and in the Victoria River district of the Northern Territory. Records were set in a number of regions, including much of the WA interior, the western Top End (NT), the central third of Victoria, northwestern Tasmania, parts of Cape York Peninsula, and around Ceduna (SA).


Areal average temperatures
  Maximum Temperature Minimum Temperature
Rank
(out of 61)
Anomaly*
(°C)
Comment Rank
(out of 61)
Anomaly*
(°C)
Comment
Australia 52 +0.93 60 +1.68 2nd highest; record is +2.05 (2005)
Queensland 31 +0.27 57 +1.41
New South Wales 44 +0.91 48 +0.80
Victoria 53 +1.34 59 +1.73 Highest since 1974
Tasmania 56 +1.34 59 +1.35 Highest since 1989
South Australia 49 +1.11 59 +2.40 3rd highest; record is +2.65 (2005)
Western Australia 57 +1.67 60 +1.94 2nd highest; record is +2.27 (2005)
Northern Territory 30 +0.19 54 +1.58

*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

Rainfall

National rainfall was 34% above normal (17th highest on record). Totals were above normal across much of northern and central Australia, including almost all of the Northern Territory, Queensland west of a Townsville-Charleville line (extending into northwestern NSW west of Walgett), most of South Australia (except the Eyre Peninsula and some areas east of the Flinders Ranges), and the eastern half of Western Australia. It was also wetter than normal in April in the western half of Victoria, as well as in the northeast ranges and south Gippsland, and in northwestern Tasmania.

The two most significant areas of above-normal rainfall were in much of northeastern South Australia, and the Gulf region extending from the eastern Northern Territory as far east as southern Cape York Peninsula. April records were set in both regions, around the Queensland/NT border on the Gulf coast, further east around Croydon, and in the Woomera-Leigh Creek area in South Australia. Other areas with totals in the highest decile included the southern NT around and east of Alice Springs, and localised areas in the WA Goldfields, the NT Top End, and west of Bourke in New South Wales.

While rainfall was below normal in many southern areas, few areas were especially dry and only small areas were in the lowest decile. The greatest concentration of such areas was on the NSW coast south of Sydney; there were also patches of such low falls scattered through the inland west of Western Australia.


Areal average rainfall
Rank
(out of 111)
Average
(mm)
Departure
from mean*
Comment
Australia 95 41.5 +34%
Queensland 93 60.8 +45%
New South Wales 48 31.5 −34%
Victoria 67 52.0 +1%
Tasmania 56 112.8 −4%
South Australia 98 26.2 +59%
Western Australia 56 20.8 Normal
Northern Territory 101 67.8 +135%
Murray-Darling Basin 67 30.1 −23%

*The mean is calculated for the 1961-1990 reference period.


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


Australian weather extremes in April 2010
Hottest day 42.8 °C at Roebourne (WA) on the 1st
Coldest day 2.1 °C at Mount Baw Baw (Vic) on the 11th
Coldest night −8.0 °C at Charlotte Pass (NSW) on the 26th
Warmest night 30.4 °C at Marble Bar (WA) on the 1st
Wettest day 358.4 mm at Centre Island (NT) on the 1st


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.

This statement has been prepared based on information available at 10 am on Monday 3 May 2010. 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.

In the tables, fractional ranks denote tied values.

A new area-averaging method was adopted for rainfall in May 2009. Current and historical totals for Tasmania are substantially higher than under the old scheme, but differences for other states, and nationally, are negligible. The rankings and departures from mean shown here use the new method.


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