Northern Territory in April 2012: Transition to the dry season

  • Record max temperatures in Alice Springs District
  • Darwin has coolest April night in 43 years
  • Tropical Low brings rainfall to north coast

Top End Transitions to dry season weather

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.

Alice Springs heat spell

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.

Tropical Low brings rain to north coast

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.

Rainfall

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.

Temperature

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.

Maximum temperature

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.

Minimum temperature

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.

Wind

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.

Other phenomena

Some other things happened too, and they are mentioned here.

Further information

Media
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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

Maps
ObservedAnomalyDecile rank
Total
rainfall
Map of Rainfall totals Map of Percentage of normal rainfall Map of Rainfall deciles
Mean
daily
maximum
temperatures
Map of Mean maximum temperature Map of Anomaly in mean maximum temperature Map of Decile rank of mean maximum temperature
Mean
daily
minimum
temperatures
Map of Mean minimum temperature Map of Anomaly in mean minimum temperature Map of Decile rank of mean minimum temperature


Record highest April daily rainfall
Highest daily rainfall
in April 2012 (mm)
Previous wettest
for April
Years of
record
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
Total rainfall
for April 2012 (mm)
Previous wettest
for April
Years of
record
Average for
April
Walungurru 10.8 3.4 in 2009 11 1.9




Record highest April temperature
Highest temperature
in April 2012 (°C)
Previous warmest
for April
Years of
record
Average for
April
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
temperature
in April 2012 (°C)
Previous coolest
for April
Years of
record
Average for
April
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
Lowest temperature
in April 2012 (°C)
Previous coolest
for April
Years of
record
Average for
April
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
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean Diff
from
average
Highest Mean Diff
from
average
Lowest Total long-term Average
Rank Fraction of
long-term
average
Darwin-Daly (district 14GA)
Batchelor Aero 33.0 -0.8 35.5 19th 21.2 -0.5 13.5 29th 29.2 103.8 average 28%
Black Point 31.9 +0.3 33.6 16th 24.6 -0.3 20.6 30th 50.8 108.4 average 47%
Bradshaw 35.1 -0.6 38.6 3rd 21.5 -0.8 13.5 28th 64.2 23.5 high 273%
Cape Don 32.7   34.5 15th 26.2   23.0 30th 80.2 139.4 average 58%
Central Arnhem Plateau 32.1   34.3 7th 20.4   13.9 29th 24.8
Channel Point 31.7 -0.7 33.8 16th 23.0 -0.5 16.5 30th 60.9 117.0 average 52%
Darwin Airport 32.9 +0.2 35.0 19th 23.6 -0.4 18.8 29th 67.6 101.1 average 67%
Delamere Weapons Range 33.0 -1.1 36.2 6th 20.5 -0.6 14.1 27th 2.8 19.8 average 14%
Douglas River 33.4 -1.1 35.7 21st 20.3 -0.1 13.1 29th 62.4 52.5 average 119%
Dum In Mirrie 33.3 +0.5 35.9 16th 23.9 -0.5 18.0 30th 28.6 99.8 low 29%
Jabiru Airport 34.8 +0.3 36.6 7th 23.4 -0.1 18.3 29th 68.0 86.9 average 78%
Katherine Country Club 33.8   36.2 12th 20.2   12.5 29th 16.4
Mango Farm 33.8 -0.5 36.0 4th 21.1 -0.5 14.2 29th 36.7 69.7 average 53%
McCluer Island 30.6 -0.1 31.9 16th 25.8 -0.1 23.8 12th 73.4 153.4 average 48%
Middle Point 34.4 +0.4 37.2 19th 21.8 -0.6 13.8 29th 45.6 107.2 average 43%
Noonamah 34.3   36.6 3rd 22.1   15.1 30th 29.4
Pirlangimpi 33.3 +0.6 35.2 10th 23.2 +0.2 17.8 29th 85.0 155.4 average 55%
Port Keats Aero 33.1 -1.4 35.9 5th 22.2 -0.1 15.6 29th
Tindal RAAF 33.6 -0.2 36.1 7th 20.1 -0.5 12.3 29th 11.4 39.5 average 29%
Arnhem (district 14BC)
Cape Wessel 31.7   32.8 6th 25.6   23.6 3rd 11.4 157.1 low 7%
Gove Airport 31.2 +0.4 32.9 5th 22.8 -0.5 19.2 29th 226.2 228.5 average 99%
Groote Eylandt Airport 32.0 -0.3 34.4 1st 21.5 -0.2 15.9 30th 55.8 184.0 average 30%
Maningrida Aero 31.9   34.3 16th 22.9   18.9 29th 119.0
Milingimbi 32.4   35.1 16th 23.2   19.6 29th 24.2
Ngayawili 31.9 +0.3 33.3 5th 23.2 -0.4 19.1 29th 136.8 180.8 average 76%
North East Island 31.7   33.5 10th 26.3   24.5 18th 45.0 184.6 average 24%
Warruwi 31.5 -0.1 33.4 17th 24.5 -0.5 22.1 30th 16.0 118.5 low 14%
Roper-Mcarthur (district 14DE)
Borroloola 33.8 +0.1 36.0 23rd 18.6 -1.7 10.9 30th 26.6 75.9 average 35%
Bulman 33.7   36.2 22nd 20.2   13.6 29th 31.8
Centre Island 31.3 -0.7 34.1 3rd 24.9 -0.4 19.2 26th 89.0 95.4 average 93%
Daly Waters 33.2 -0.6 36.0 6th 19.6 -0.1 14.3 26th 21.0 22.5 high 93%
Larrimah 32.8 -1.1 35.7 6th 18.6 -1.2 11.1 27th 10.4 32.3 average 32%
McArthur River Mine 34.0 -0.7 36.6 6th 20.5 -0.1 13.2 29th 5.8 33.1 average 18%
Ngukurr 32.5 -1.4 35.4 5th 21.8 -0.2 17.0 26th 91.2 55.9 high 163%
Wollogorang 33.0 -0.7 36.3 5th 18.9 -0.8 12.5 28th 3.8 45.2 low 8%
Victoria (district 14F)
Kidman Springs 33.9 -1.5 37.6 6th 19.8 -0.9 11.9 28th 59.5 25.2 high 236%
Lajamanu 31.9 -1.7 37.4 5th 17.3 -0.7 8.7 27th 50.4 15.1 v high 334%
Timber Creek 34.2 -1.0 37.4 6th 20.1 -1.0 11.9 27th 16.8 30.1 average 56%
Victoria River Downs 33.1 -1.4 36.3 3rd 18.9 -0.9 9.6 29th 14.6 23.0 average 63%
Wave Hill 32.0 -2.2 36.5 6th 17.9 -0.9 9.7 28th 16.6 19.8 high 84%
Barkly (district 15A)
Brunette Downs 31.8 -1.7 37.2 5th 17.7 -1.5 10.5 27th 29.3 15.1 high 194%
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%
Arltunga 26.6 -2.4 37.0 3rd 12.7 -0.8 4.6 28th 20.6 16.1 high 128%
Curtin Springs 28.4 -0.8 38.6 3rd 13.8 +0.3 6.2 26th 25.8 15.7 high 164%
Jervois 29.8 -0.7 39.1 4th 15.0 +0.7 9.0 26th 7.4 17.8 average 42%
Kulgera 27.8 -0.1 37.5 2nd 13.5 -0.3 4.5 12th 18.8 13.7 high 137%
Papunya 29.5 -2.6 38.8 3rd 16.0   7.1 26th 14.9 16.3 high 91%
Rabbit Flat 32.7 -1.2 40.7 4th 17.2 +0.5 8.9 27th 11.2 20.9 average 54%
Territory Grape Farm 28.9 -1.6 37.3 4th 14.7 +0.3 7.0 26th 49.0 17.7 high 277%
Walungurru 32.4   41.1 3rd 19.5   12.6 27th 10.8 1.9 highest 568%
Yulara Aero 28.3 -1.6 38.7 2nd 14.0 -0.4 6.1 26th 31.4 13.6 high 231%

Notes

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 decile ranking (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.

Further information

Media
(03) 9669 4057
Enquiries