Northern Territory in February 2012: The "build up" revisited

  • Dry conditions across the Top End
  • Darwin Airport: 3rd hottest 3 month period (December--February)
  • Tindal RAAF sets several temperature records

Dry conditions in the Top End

While February 2011 was the wettest of any month on record in the Northern Territory, in stark contrast February 2012 was marked by a prolonged break in the North Australian Monsoon. Nearly all stations north of the Alice Springs District reported below average rainfall for the month. Shoal Bay and Channel Point both measured their lowest February rainfall on record. Dum-In-Mirrie and Batchelor Aero had their second driest February on record. For most of the month build up-like conditions prevailed with high temperatures and isolated afternoon thunderstorms.

For the 2011/12 wet season to the end of January, the Northern Territory had seen above average rainfall, although the rains had been off-and-on. After a dry February, most places are sitting at a little below average for their wet season totals, with two months still to go in the northern wet season.

Tindal RAAF temperature records

For most of the month, Tindal RAAF was on track to have their hottest February on record, however cooler temperatures returned in the last week, resulting in their second highest February mean daily maximum temperature on record, with 35.7 °C. The record of 35.8 °C was set in 1986. The minimum temperatures at Tindal RAAF had a peak near the 5th of the month and then remained below normal for the rest of the month. The February mean daily minimum temperature at Tindal RAAF was 23.1 °C, 1.1 °C below average and a new mean daily minimum temperature record for them. The previous record ( 23.5 °C) was set in 1993. The monthly average diurnal range at Tindal RAAF was 12.6 °C, also a new February record for them. The average February diurnal temperature range is 9.7 °C and the previous record was 11.7 °C set in 1986.

Darwin has 3rd hottest 'summer' period

Darwin Airport had a mean maximum temperature of 32.8 °C for the period of 1 December through 29 February. This is 0.9 °C above average and the 3rd hottest 'summer' period on record. The record is 33.0 °C, set in 1969.

Rainfall

The Madden-Julian Oscillation (MJO) is the large scale climate driver responsible for the "bursts" and "breaks" in the North Australian Monsoon. The end of January up to 1 February was marked by a significant burst in monsoon conditions. As the Madden-Julian Oscillation moved east, away from Australia, the Top End was left with relatively dry build up-like conditions in a monsoon break that lasted the whole month. Typical build-up conditions include isolated afternoon thunderstorms across the Top End. These storms brought some rain to many Top End locations, but by the end of the month most of the northern half of the NT had below to well below average rainfall totals. Darwin Airport ended the month with 250.2 mm, only 67% of the long-term average (374.3 mm). Gove Airport had 122.4 mm which is less than half of their February average (283.1 mm).

The Alice Springs District saw little rainfall for most of the month, but toward the end of the month, a series of northwest cloud bands brought some showers the region. Alice Springs Airport had 43.0 mm this month, which is near their long-term average. Yulara had 32.8 mm, just under their long term average, but well over the median February rainfall of 12 mm.

The wettest overall was Pirlangimpi with 379.4 mm, followed by Majestic Orchids with 335.2 mm and then Rosebery with 320.0 mm.

The driest overall was Palm Valley with 0 mm, followed by Yuendumu with 3.7 mm, and then Montejinni with 12.0 mm.

While no stations record their highest total February rainfall this month, several sites had their lowest total February rainfall on record including Wollogorang and Shoal Bay.

February 1st was the wettest single day around the Territory , with CSIRO Berrimah measuring 171.6 mm, Karama having 158.4 mm, and Leanyer had 156.6 mm.

Some sites, including Hidden Valley and Upper Bond Springs, had their highest February daily rainfall on record. There is a map of rainfall deciles below.

Temperature

The warmest stations on average were Walungurru and Wave Hill both with 31.1 °C, followed by Ngukurr with 30.9 °C. The coolest on average was Arltunga with 26.2 °C, followed by Alice Springs Airport with 26.8 °C, and then Yulara Aero with 27.5 °C.

Maximum temperature

Most places saw above average maximum temperatures for February, primarily due to decreased cloud cover across the Top End for most of the month. The mean daily maximum temperature for Darwin Airport this month was 32.4 °C, 1 °C above the long-term average. There were no mean daily maximum temperature records set this month, but worth noting is Tindal RAAF, which had its second hottest February on record, and the hottest February since 1986. Mango farm, Dum-In-Mirrie, Pirlangimpi and Delemere Weapons Range also had their second highest February mean daily maximum temperatures.

The hottest daily maximum temperature around the Territory this month was at Walungurru with 44.2 °C on the 16th, followed by Yulara Aero with 43.5 °C on the 17th. The warmest days on average were at Wave Hill with 38.8 °C, followed by Rabbit Flat with 38.7 °C, and then Lajamanu with 38.5 °C.

Yulara Aero also had the lowest daily maximum temperature this month with 21.0 °C on the 29th when a thick cloud band and heavy rainfall moved over the southwest corner of the Territory. The next coolest days were at Jervois with 23.1 °C on the 22nd and Curtin Springs with 23.3 °C on the 29th. The coolest days on average were at McCluer Island with 31.2 °C, followed by Black Point with 31.5 °C, and Cape Wessel with 31.6 °C.

Jabiru Airport tied their highest February temperature on record while Mango Farm, Dum-In-Mirrie and Pirlangimpi all set new daily maximum temperature records for February. There is a map of maximum temperature anomalies below.

Minimum temperature

As a very dry air mass moved slowly over the southern and central parts of the Territory early in the month, many places saw daily minimum temperatures drop to all-time lows. Yulara Aero had their lowest February temperature on record with 12.1 °C on the 7th. Several sites had their lowest February mean daily minimum temperature on record, including Tindal RAAF with 23.4 °C, Yulara Aero with 13.9 °C and Groote Eylandt Airport with 23.9 °C. Daly Waters set a new mean daily minimum temperature record this month with 21.5 °C, breaking the 63-year record of 21.9 °C set in 1941. On the 17th the minimum temperature at Rabbit Flat was 29.5 °C, which ties their warmest February night (highest daily minimum temperature) on record set on the 9th in 2005. There is a map of minimum temperature anomalies below.

The coldest night was at Arltunga with 10.4 °C on the 9th, followed by Alice Springs Airport with 10.8 °C on the 7th, and Arltunga again with 11.2 °C on the 3rd. The coolest nights on average were at Alice Springs Airport with 18.0 °C, followed by Arltunga with 18.4 °C, and Yulara Aero with 19.3 °C.

The warmest nights on average were at Centre Island with 26.7 °C followed by North East Island with 26.4 °C. The warmest night was at Centre Island with 30.0 °C on the 6th, followed by Rabbit Flat with 29.5 °C on the 17th (a new record for Rabbit Flat), and then Centre Island with 29.2 °C on the 5th.

Wind

The strongest wind gust was 89 km/h at Territory Grape Farm on the 17th, followed by Bradshaw with 85 km/h on the 15th, and Borroloola with 85 km/h on the 17th, these were followed by Cape Wessel with 80 km/h on the 3rd.

Further information

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Extremes in February 2012
Hottest day 44.2 °C at Walungurru on the 16th
Warmest days on average 38.8 °C at Wave Hill
Coolest days on average 31.2 °C at McCluer Island
Coldest day 21.0 °C at Yulara Aero on the 29th
Coldest night 10.4 °C at Arltunga on the 9th
Coolest nights on average 18.0 °C at Alice Springs Airport
Warmest nights on average 26.7 °C at Centre Island
Warmest night 30.0 °C at Centre Island on the 6th
Warmest on average overall 31.1 °C at Walungurru
Coolest on average overall 26.2 °C at Arltunga
Wettest overall 379.4 mm at Pirlangimpi
Driest overall 0 mm at Palm Valley
Wettest day 171.6 mm at CSIRO Berrimah on the 1st
Highest wind gust 89 km/h at Territory Grape Farm on the 17th

Maps

Anomaly in mean maximum temperature

Map of Anomaly in mean maximum temperature

Anomaly in mean minimum temperature

Map of Anomaly in mean minimum temperature

Rainfall deciles

Map of Rainfall deciles


Record highest February daily rainfall
Highest daily rainfall
in February 2012 (mm)
Previous wettest
for February
Years of
record
Yambah 97.0 on the 29th 75.6 on the 25th in 1974 45
Hidden Valley 147.5 on the 25th 105.2 on the 17th in 1991 33
Roper River Mataranka 116.5 on the 24th 97.5 on the 26th in 2003 11
Upper Bond Springs 42.0 on the 29th 34.0 on the 21st in 2002 11
Yeuralba Ridge 77.2 on the 25th 70.0 on the 9th in 2004 10



Record lowest total February rainfall
Total rainfall
for February 2012 (mm)
Previous driest
for February
Years of
record
Average for
February
Montejinni 12.0 38.5 in 2007 42 164.9
Wollogorang 68.1 70.5 in 1978 37 248.4
Palm Valley 0.0 = 0.0 in 2007 31 51.1
Keep River Rangers 37.9 57.4 in 2005 30 207.4
Channel Point 181.8 192.2 in 2005 22 411.7
Shoal Bay 21.4 153.5 in 1992 17 439.0
Walker Creek 116.2 176.8 in 2006 17 483.9




Record highest February temperature
Highest temperature
in February 2012 (°C)
Previous warmest
for February
Years of
record
Average for
February
Jabiru Airport 37.7 on the 14th = 37.7 on the 19th in 1983 36 33.1
Mango Farm 37.9 on the 14th 37.7 on the 22nd in 1996 31 33.1
Pirlangimpi 35.0 on the 17th 34.9 on the 19th in 2010 31 31.4
Dum In Mirrie AWS 34.4 on the 18th 33.8 on the 19th in 2010 14 31.1




Record highest February daily minimum temperature
Highest daily minimum
temperature
in February 2012 (°C)
Previous warmest
for February
Years of
record
Average for
February
Rabbit Flat 29.5 on the 17th = 29.5 on the 9th in 2005 16 23.6



Record lowest February temperature
Lowest temperature
in February 2012 (°C)
Previous coolest
for February
Years of
record
Average for
February
Larrimah 16.5 on the 9th 18.5 on the 4th in 1990 47 23.7
Victoria River Downs 17.0 on the 9th 17.4 on the 11th in 1996 46 24.5
Gove Airport 20.1 on the 11th 20.2 on the 9th in 1987 33 24.6
Elliott 15.7 on the 9th 16.2 on the 11th in 1996 31 23.8
Timber Creek 19.4 on the 9th = 19.4 on the 4th in 1996 31 24.6
Alyangula Police 20.5 on the 19th 21.1 on the 16th in 1993 30 25.6
Yulara Aero 12.1 on the 7th 12.5 on the 4th in 2005 26 22.2
Tindal RAAF 18.3 on the 10th 19.2 on the 3rd in 1997 25 24.2
Borroloola 18.4 on the 9th 20.3 on the 10th in 1996 19 24.7
Kidman Springs 17.6 on the 9th 19.1 on the 12th in 2005 17 24.7
Groote Eylandt Airport AWS 19.6 on the 11th 21.0 on the 23rd in 2001 13 25.0
Ngayawili 21.9 on the 7th 22.0 on the 27th in 2004 13 25.6



Record lowest February mean daily minimum temperature
Mean daily minimum
temperature
for February 2012 (°C)
Previous coolest
for February
Years of
record
Average for
February
Larrimah 22.3 22.8 in 1975 46 23.7
Victoria River Downs 23.2 = 23.2 in 1966 45 24.5
Daly Waters AWS 21.5 21.9 in 1941 42 23.5
McArthur River Mine 23.0 23.7 in 1976 34 24.7
Timber Creek 23.4 23.8 in 1981 30 24.6
Yulara Aero 19.3 19.4 in 2002 25 22.2
Tindal RAAF 23.1 23.5 in 1993 24 24.2
Borroloola 22.2 23.7 in 2005 18 24.7
Batchelor Aero 23.3 23.4 in 2011 16 23.8
Groote Eylandt Airport AWS 23.9 24.4 in 2011 12 25.0
Arltunga 18.4 18.8 in 2005 10 21.3
Middle Point AWS 23.5 23.6 in 2007 10 24.0





Notes

This statement has been prepared based on information available at 1 pm on Thursday 1 March 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.

Further information

Media
(03) 9669 4057
Enquiries