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Monday, 30 April 2012 - Monthly Climate Summary for Northern Territory - Product code IDCKGC12R0
Late April and early May mark the transition from wet season to dry season conditions across tropical Australia. One key indicator of dry season weather is the dew point temperature. In the early hours of Friday the 27th the dew point temperature dropped below 15 °C for more than two hours. Overnight minimum temperatures also saw a drop throughout the month. Darwin Airport had two nights this month that dropped below 20 °C, these were the 29th and 30th with 18.8 °C and 19.4 °C respectively.
For the first few days of the month winds shifted to north east in Alice Springs, ahead of a very slow moving trough. This northerly wind caused the temperature to rise across the region. For several days the temperature lingered above 36 °C from the 1st to the 5th of the month. These five days set a new April record at Alice Springs Airport of the most consecutive days above 36 °C. For three days from the 2nd to the 4th the maximum temperature reached 38 °C which is also a record heat spell for April. The hottest April day on record at Alice Springs Airport is 2 April 2005, when the temperature reached 39.9 °C.
On 16 April, a low pressure system formed over the Arafura Sea and moved west into the Timor Sea from the 17th to the 21st. While the system never moved over land, locations along the north coast picked up some rainfall from the event.
As a low pressure system moved along the north coast, several locations recorded significant rainfall totals. Gove Airport recorded 75.8 mm on the 18th, Pirlangimpi had 48 mm on the 21st and Darwin Airport had 39 mm on the 24th.
There were two daily rainfall records set this month. Bradshaw measured 59.0 mm on the 24th, breaking the previous record of 41.2 mm set on the 2nd of April 2011. Walungurru had 7 mm on the 6th which broke the old record of 2.2 mm set on 23 April 2009. Walungurru ended the month with 10.8 mm, which is their highest total April rainfall on record, their old record was 3.4 mm set in 2009. There is a map of rainfall deciles below.
Gove Airport had the highest monthly total this month with 226.2 mm, followed by Alyangula Police with 215.4 mm, and then Yirrkala Tropical Gardens with 200.0 mm. The wettest single day was at Dorisvale Crossing with 84.0 mm on the 25th, followed by Maningrida Aero with 78.2 mm on the 20th, and then Yirrkala Tropical Gardens with 78.0 mm on the 18th.
The mean temperature (average of maximum and minimum) for the Northern Territory for April 2012 was 24.83 °C which is 0.6 ° C below the long term average. The warmest on average was Cape Don with 29.6 °C, followed by Jabiru Airport with 29.2 °C, and then North East Island with 29.0 °C. The coolest on average was Arltunga with 19.8 °C, followed by Alice Springs Airport with 20.6 °C, and then Curtin Springs and Kulgera both with a mean monthly temperature of 21.2 °C.
The month began very warm in the Alice Springs District, with several locations measuring above 36 °C for the first 5 days of the month. There were several sites that had their highest April temperature on record during the first week of the month including; Yuendumu, Rabbit Flat and Papunya. Alice Springs Airport measured a record 5 days in April above 36 °C which included three days above 38 °C. Throughout the rest of the month maximum temperatures fluctuated significantly, at times dropping over 10 degrees below the long term average for the region. By the end of the month most places, including Alice Springs Airport, had a mean maximum temperature that was near the long-term average.
Walungurru experienced the hottest day in the Territory this month with 41.1 °C on the 3rd, followed by Rabbit Flat with 40.7 °C on the 4th, and then Walungurru again with 40.5 °C on the 2nd. The warmest days on average were at Bradshaw with 35.1 °C, followed by Jabiru Airport with 34.8 °C, and then Middle Point with 34.4 °C.
Yulara Aero had the coldest day with a daily maximum temperature of 16.7 °C on the 22nd, followed by Papunya with 17.3 °C on the 12th, which tied with Kulgera lowest maximum of 17.3 °C on the 22nd. Curtin Springs also had a notable low maximum on the 22nd with 17.5 °C. The coolest days on average were at Arltunga with 26.6 °C, followed by Kulgera with 27.8 °C, and then Alice Springs Airport with 27.9 °C. There is a map of maximum temperature anomalies below.
The average minimum temperature across the whole Territory was 18.47 °C which is 0.6 below the long term average for April.
On the 29th the minimum temperature at Darwin Airport dropped to 18.8 °C. This is the lowest April minimum temperature at Darwin Airport in 43 years, taking us back to 18 April 1969 when the minimum temperature was 18.3 °C. While this is not a new record for Darwin Airport, several places had their lowest April temperature on record this month, including Black Point with 20.6 °C and Dum In Mirrie with 18.0 °C on the 30th. There is a map of minimum temperature anomalies below.
The coldest night was at Alice Springs Airport with 4.4 °C on the 26th, followed by Kulgera with 4.5 °C on the 12th. The coolest nights on average for the month were at Arltunga with 12.7 °C, followed by Alice Springs Airport with 13.0 °C, and then Kulgera with 13.5 °C.
The warmest night was at Cape Don with 28.4 °C on the 18th, followed by McCluer Island which had 28.1 °C on the 4th again on the 7th, North East Island also had 28.1 °C on the 11th and on the 16th. The warmest nights on average this month were at North East Island with 26.3 °C, followed by Cape Don with 26.2 °C, and then McCluer Island with 25.8 °C.
The strongest wind gust this month was at McCluer Island with 69 km/h on the 12th. There were two stations that measured a wind gust of 67 km/h, these were Walungurru on the 5th and Centre Island on the 13th. The highest wind gust at Darwin Airport this month was 65 km/h on the 1st.
Some other things happened too, and they are mentioned here.
|Extremes in April 2012|
|Hottest day||41.1 °C at Walungurru on the 3rd|
|Warmest days on average||35.1 °C at Bradshaw|
|Coolest days on average||26.6 °C at Arltunga|
|Coldest day||16.7 °C at Yulara Aero on the 22nd|
|Coldest night||4.4 °C at Alice Springs Airport on the 26th|
|Coolest nights on average||12.7 °C at Arltunga|
|Warmest nights on average||26.3 °C at North East Island|
|Warmest night||28.4 °C at Cape Don on the 18th|
|Warmest on average overall||29.6 °C at Cape Don|
|Coolest on average overall||19.8 °C at Arltunga|
|Wettest overall||226.2 mm at Gove Airport|
|Wettest day||84.0 mm at Dorisvale Crossing on the 25th|
|Highest wind gust||69 km/h at McCluer Island on the 12th|
|Record highest April daily rainfall|
Highest daily rainfall
in April 2012 (mm)
|Bradshaw||59.0||on the 24th||41.2||on the 2nd in 2011||11|
|Walungurru||7.0||on the 6th||2.2||on the 23rd in 2009||11|
|Record highest total April rainfall|
for April 2012 (mm)
|Record highest April temperature|
in April 2012 (°C)
|Yuendumu||39.0||on the 4th||38.5||on the 10th in 2005||45||30.1|
|Rabbit Flat||40.7||on the 4th||40.6||on the 3rd in 2005||16||33.9|
|Middle Point||37.2||on the 19th||37.0||on the 17th in 2003||11||34.0|
|Record lowest April daily maximum temperature|
Lowest daily maximum
in April 2012 (°C)
|Douglas River||26.7||on the 25th||= 26.7||on the 24th in 2000||19||34.5|
|Delamere Weapons Range||23.2||on the 25th||24.0||on the 6th in 2006||13||34.1|
|Arltunga||18.1||on the 25th||19.5||on the 22nd in 2001||11||29.0|
|Bradshaw||25.8||on the 25th||26.3||on the 26th in 2006||11||35.7|
|Record lowest April temperature|
in April 2012 (°C)
|Black Point||20.6||on the 30th||20.9||on the 28th in 2008||19||24.9|
|Channel Point||16.5||on the 30th||17.0||on the 27th in 2008||18||23.5|
|Dum In Mirrie||18.0||on the 30th||18.2||on the 26th in 2008||14||24.4|
|Bradshaw||13.5||on the 28th||14.0||on the 26th in 2008||11||22.3|
|Middle Point||13.8||on the 29th||15.1||on the 27th in 2008||11||22.4|
|Summary statistics for April 2012|
|Darwin-Daly (district 14GA)|
|Central Arnhem Plateau||32.1||34.3||7th||20.4||13.9||29th||24.8|
|Delamere Weapons Range||33.0||-1.1||36.2||6th||20.5||-0.6||14.1||27th||2.8||19.8||average||14%|
|Dum In Mirrie||33.3||+0.5||35.9||16th||23.9||-0.5||18.0||30th||28.6||99.8||low||29%|
|Katherine Country Club||33.8||36.2||12th||20.2||12.5||29th||16.4|
|Port Keats Aero||33.1||-1.4||35.9||5th||22.2||-0.1||15.6||29th|
|Arnhem (district 14BC)|
|Groote Eylandt Airport||32.0||-0.3||34.4||1st||21.5||-0.2||15.9||30th||55.8||184.0||average||30%|
|North East Island||31.7||33.5||10th||26.3||24.5||18th||45.0||184.6||average||24%|
|Roper-Mcarthur (district 14DE)|
|McArthur River Mine||34.0||-0.7||36.6||6th||20.5||-0.1||13.2||29th||5.8||33.1||average||18%|
|Victoria (district 14F)|
|Victoria River Downs||33.1||-1.4||36.3||3rd||18.9||-0.9||9.6||29th||14.6||23.0||average||63%|
|Barkly (district 15A)|
|Tennant Creek Airport||30.3||-1.3||36.9||4th||19.2||-1.2||12.0||26th||69.2||17.5||v high||395%|
|Alice Springs (district 15B)|
|Alice Springs Airport||27.9||-0.3||38.9||3rd||13.0||+0.4||4.4||26th||25.4||16.5||high||154%|
|Territory Grape Farm||28.9||-1.6||37.3||4th||14.7||+0.3||7.0||26th||49.0||17.7||high||277%|
A Monthly Climate Summary is prepared to list the main features of the weather in Northern Territory 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.
This statement has been prepared based on information available at 1 pm on Monday 30 April 2012. Some checks have been made on the data, but it is possible that results will change as new information becomes available.
Averages are 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.
The median is sometimes more representative than the mean of long-term average rain.
The Rank indicates how rainfall this time compares with the climate record for the site,
based on the
(very low rainfall is in decile 1, low in decile 2 or 3,
average in decile 4 to 7, high in decile 8 or 9
and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.