Northern Territory in May to September 2012: Cool and Dry

The 2012 dry season was exceptionally dry across the Territory with a few records noted. A strong sub-tropical ridge, a persistent pattern of high pressure over the central continent, was the dominant climate driver throughout the season, blocking troughs and cold fronts from reaching the southern NT. These high pressure systems also pushed cool and dry air into the Territory allowing for cool days and cold nights and several minimum temperature records were set this season. Due to the dry gusty conditions, frequent bushfires occurred over the Top End. Fogs were also recorded during the dry season especially along the coasts in the Top End.

  • Record dry spell in southern Northern Territory
    • 157 days without rain at Alice Springs
  • Alice Springs record cold streak
    • 5 consecutive nights below -4 °C
  • Darwin Airport 21 days with observed fog
  • Bushfires across the Territory

Record dry spell at Alice Springs Airport

Alice Springs Airport experienced 157 consecutive days without rain this year. The dry spell began on 25 April and lasted until 28 September. Finally, on 29 September 3 mm of rain fell ending the dry spell. The Alice Springs District usually records about 65 mm of rain between May and September, inclusive. This year, however, the strong sub-tropical ridge which persisted across the Australia Continent for the entire season prevented rain bearing systems such as fronts or shallow troughs from moving into the Territory. The previous record for the longest dry spell at Alice Springs Airport was set in 1972 with 147 consecutive days without rain.

Bushfires in Northern Territory

High fuel load accumulated, after two wet years in a row, combined with dry and gusty southeast winds raised the fire danger index (FDI) across the Territory. Fire dangers were also raised through the passage of shallow weak troughs propagating eastwards across the southern Northern Territory, especially ahead of the trough warm and gusty northwest winds. There were 3 events that the FDI's reached the "extreme" level in the NT this dry season. Significant fires were reported in every month of the dry season; August and September were especially bad in the Top End and throughout the red centre. A total of 52 fire ban days were issued by fire authorities during the dry season for various Fire Protection Zones across the Territory.

Darwin Airport Fog

Twenty-one fog days were observed at the Darwin Airport during the dry season. Clear skies and low level moisture over the Top End resulted in fog formation, including sea fog, shallow, and patchy fog. Fog formation was not limited to the Darwin area, but was over the Top End especially along the coast and in the Gulf country all season. This sets a new record for number of fog days observed at the Darwin Airport, the previous record was 11 fog days observed in the dry season on 1961.

Alice Springs cold streak

Alice Springs experience below average night-time temperatures almost throughout June, July and August (In July only two nights saw minimum temperatures above the monthly average of 4.1 °C). During this winter season (June, July, August) Alice Springs endured 37 nights at or below 0 °C. This included 5 consecutive nights from 3 July to 7 July, inclusive, of temperatures at or below -4 °C, the longest cold spell of that magnitude on record at Alice Springs Airport. These cold nights were caused by a series of high pressure systems that propagated eastwards across southern Australia. These highs pushed cold, dry southern air into the territory which in turn dipped the night-time temperatures throughout most of the NT.

Rainfall

Most of the dry season was significantly dry for most of the Northern Territory. A series of high pressure systems over central Australia blocked any rain bearing systems from raining on the NT. Even in the Alice Springs District, which usually sees between 60-70 mm fall this time of year, did not receive any rain until the last days of September.

The dry season was not all dry, the Top End experienced two rain events this season. This first included showers and storms in the first few week of May. Rain bands associated with a tropical low located over the Timor Sea in the beginning of May recorded significant rainfall totals along the north coast. Some of these totals included 36.6 mm on 10 May at Jabiru Airport, breaking the previous May daily rainfall record of 22.2 mm set on the 22 of May 1990. Wagait Beach had 48.2 mm on the 3rd which is the highest May to September daily rainfall on record for them.

The second rainfall event occurred in the early morning of 30 September. A mobile trough moved slowly across the NT creating a northwest cloud band on the 29th which brought light rain to the Alice Springs District, ending Alice Springs' 157 day, record long, dry spell. The trough slowly moved north and by the time it reached the Top End, early on the 30th, it not only caused broad scale cloudiness and light rain, but also induced surface based convection in some areas causing significant rainfall which exceeded long term monthly mean for many locations.

Most mid-season rainfall was recorded along the northern and eastern parts of the Top End, especially Arnhem land and the Gove peninsula, where low level moisture was abundant. Shallow and weak westward propagating gulf lines were also the major factor for precipitation over the eastern Top End. The wettest overall in the NT for the season was Gove Airport with 214.0 mm, followed by McCluer Island with 144.2 mm, followed by North East Island with 112.6 mm.

The wettest single day was at McCluer Island with 90.6 mm on 10 May, followed by Wongalara with 64.8 mm on 30 Sep, followed by Yirrkala Tropical Gardens with 62.0 mm on 25 May.

Maximum temperature

Maximum temperatures across the NT were generally near average for the dry season. Some sites ended the season with a mean daily maximum temperature above average while other sites were below average. When averaged across the NT, maximum temperatures were 0.3 °C above average for the dry season. However, toward the end of September daily maximum temperatures rose significantly. The maximum temperatures across the Northern Territory recorded about 1 to 3 °C greater than the September monthly maximum of 31.38 °C, except along the northwest coast which is just below the average due to the sea breeze. Increasing solar exposure increased the daily maximum temperatures especially across the central Australia (about 4 °C greater then September average). Near the end of September some places, including Alice Springs Airport and Territory Grape Farm, tied or exceeded their highest May to September temperature on record.

The hottest day was at Lajamanu with 41.1 °C on 23 Sep, followed by Bulman with 41.0 °C on 27 Sep, and then Daly Waters with 40.9 °C on 27 Sep; a new record for each. The warmest days on average in the NT for May to September were at Middle Point and Noonamah with 33.7 °C, followed by Jabiru Airport with 33.4 °C, and then Batchelor Aero and Douglas River with 32.5 °C.

The coolest days on average were at Arltunga with 22.2 °C, followed by Alice Springs Airport with 23.4 °C, and then Yulara Aero with 23.6 °C. The coldest days were all at Arltunga with 13.2 °C on 2 July, followed by 13.5 °C on 22 and 24 June, and then 13.6 °C on 23 June.

Minimum temperature

Minimum temperatures were below average to lowest on record across the NT this dry season. When average across the NT minimum temperatures were 1.6 °C below the long-term average of 13.4 °C. When comparing just the winter months, June through August, the NT experienced the coldest winter on record with minimum temperatures on average 2 °C below average. As mentioned above, Alice Springs had 37 nights at or below 0 °C, including 5 consecutive nights from 3 July to 7 July with temperatures at or below -4 °C. At Darwin Airport the daily minimum temperature dropped below 20 °C for 85 nights. With -4.8 °C on 7 July, Kulgera had their lowest May to September temperature on record. VRD, Mango Farm, and Yulara Aero all had their lowest May to September mean daily minimum temperature on record.

The coldest night was at Alice Springs Airport with -5.2 °C on 7 July, followed by Alice Springs Airport with -4.9 °C on 3 July, and then Kulgera with -4.8 °C on 7 July. The coolest nights on average were at Alice Springs Airport with 4.0 °C, followed by Arltunga with 4.7 °C, and then Curtin Springs with 4.8 °C.

The warmest nights on average were at Cape Wessel with 23.6 °C, followed by Cape Don and McCluer Island with 23.2 °C, and then North East Island with 22.3 °C. The warmest nights were at North East Island with 27.2 °C on 5 May, followed by 26.9 °C on 13 May and again on 14 May.

Wind

The strongest wind gust was at Darwin Harbor NTC with 83 km/h on 17 Aug, followed by Cape Wessel with 78 km/h on 25 May and Centre Island also with 78 km/h on 5 Jul, and then Central Arnhem Plateau with 72 km/h on 29 Sep.

Further information

Media
(03) 9669 4057
Enquiries

Extremes in May to September 2012
Hottest day 41.1 °C at Lajamanu on 23 Sep
Warmest days on average 33.7 °C at Middle Point AWS
33.7 °C at Noonamah AWS
Coolest days on average 22.2 °C at Arltunga
Coldest day 13.2 °C at Arltunga on 2 Jul
Coldest night -5.2 °C at Alice Springs Airport on 7 Jul
Coolest nights on average 4.0 °C at Alice Springs Airport
Warmest nights on average 23.6 °C at Cape Wessel
Warmest night 27.2 °C at North East Island on 5 May
Warmest on average overall 26.7 °C at Cape Don
Coolest on average overall 13.4 °C at Arltunga
Wettest overall 214.0 mm at Gove Airport
Wettest day 90.6 mm at McCluer Island on 10 May
Highest wind gust 83 km/h at Darwin NTC AWS on 17 Aug

Record highest May to September daily rainfall
Highest daily rainfall
in May to September 2012 (mm)
Previous wettest
for May to September
Years of
record
Wagait Beach 48.2 on 3 May 44.0 on 17 Jul 2001 21



Record highest total May to September rainfall
Total rainfall
for May to September 2012 (mm)
Previous wettest
for May to September
Years of
record
Average for
May to September
Wollogorang 65.4 65.1 in 1992 31 13.4



Record highest May to September temperature
Highest temperature
in May to September 2012 (°C)
Previous warmest
for May to September
Years of
record
Average for
May to September
Alice Springs Airport 38.8 on 22 Sep = 38.8 on 22 Sep 2003 70 22.5
Daly Waters AWS 40.9 on 27 Sep 40.0 on 26 Sep 2003 40 30.8
Lajamanu 41.1 on 23 Sep 40.3 on 21 Sep 2009 15 29.3
Territory Grape Farm 38.2 on 27 Sep 38.0 on 22 Sep 2003 11 25.2



Record lowest May to September temperature
Lowest temperature
in May to September 2012 (°C)
Previous coolest
for May to September
Years of
record
Average for
May to September
Kulgera -4.8 on 7 Jul -4.7 on 15 Jul 1982 29 7.4



Record lowest May to September mean daily minimum temperature
Mean daily minimum
temperature
for May to September 2012 (°C)
Previous coolest
for May to September
Years of
record
Average for
May to September
Victoria River Downs 10.5 10.9 in 1976 39 14.1
Mango Farm 14.5 14.6 in 1994 29 16.9
Yulara Aero 5.0 5.1 in 1994 22 7.3



Summary statistics for May to September 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
average
Darwin-Daly (district 14GA)
Batchelor Aero 32.5 -0.6 38.4 23 Sep 16.3 -1.7 8.5 7 Jun 55.4 29.0 high 191%
Black Point     34.2 15 Sep 21.3 -0.7 17.0 13 Aug 89.4 46.6 high 192%
Cape Don 30.2   33.5 16 Sep 23.2   19.4 22 Jul 76.2 45.0 high 169%
Central Arnhem Plateau 30.3   38.3 27 Sep 15.9   8.8 13 Aug 23.2
Darwin Airport 31.3 -0.1 36.2 9 Sep 19.4 -1.5 13.1 13 Aug 74.4 45.0 high 165%
Delamere Weapons Range 31.2 -0.2 39.5 22 Sep     9.5 11 Jun 1.0 13.1 average 8%
Douglas River 32.5 -0.7 40.2 23 Sep 13.7 -1.4 3.4 4 Jul 13.0 21.7 average 60%
Dum In Mirrie AWS 30.5 -0.5 35.6 10 Sep 18.8 -1.6 12.6 23 Jul 9.0 34.4 low 26%
Jabiru Airport 33.4 0.0 39.8 27 Sep 19.3 -0.8 12.1 22 Jul 70.6 24.0 high 294%
Katherine Country Club 32.3   40.4 28 Sep 14.6   7.0 11 Jun 29.4
Mango Farm 32.4 -0.7 40.0 24 Sep 14.5 -2.4 7.0 13 Aug 9.4 21.6 average 44%
McCluer Island 27.8 -0.6 31.8 1 Sep 23.2 -0.6 19.8 24 Jun 144.2 62.9 high 229%
Middle Point AWS 33.7 +0.1 38.8 24 Sep 14.8 -1.8 5.0 13 Aug 51.8 38.5 high 135%
Noonamah AWS 33.7   39.3 24 Sep 16.1   8.6 13 Aug 47.8
Pirlangimpi 32.0 +0.1 36.8 23 Sep 19.2 -0.6 13.5 7 Jun 43.4 64.8 average 67%
Port Keats Aero 31.3 -0.8 36.4 16 Sep 17.2 -0.9 10.6 21 Jun
Arnhem (district 14BC)
Cape Wessel 29.4   32.3 25 Sep 23.6   21.1 12 Aug 7.0 155.2 v low 5%
Gove Airport 28.5 -0.4 33.5 18 Sep 19.8 -0.8 13.7 17 Aug 214.0 151.9 high 141%
Groote Eylandt Airport AWS 29.3 -1.0 35.5 27 Sep 16.4 -0.2 8.4 13 Aug 78.8 38.5 high 205%
Maningrida Aero 30.9   35.1 27 Aug 18.4   10.7 22 Jul 32.6
Milingimbi AWS 30.8   34.3 9 Sep 19.3   12.4 13 Aug 29.6
Ngayawili 29.9 -0.6 33.7 19 Sep 19.8 -0.6 12.9 6 Jun 21.2 49.9 average 42%
North East Island 27.1   31.9 27 Sep 22.3   18.6 16 Aug 112.6 40.3 v high 279%
Warruwi 29.8 +0.1 33.9 17 Sep 21.6 -0.9 16.9 13 Aug 1.4 20.6 low 7%
Roper-Mcarthur (district 14DE)
Bulman AWS 31.8   41.0 27 Sep 13.9   5.3 22 Jul 74.8
Centre Island 27.4 -0.7 33.6 17 Sep 19.4 -1.0 14.7 4 Jul 29.0 21.7 high 134%
McArthur River Mine 31.6 -0.2 39.3 27 Sep 12.9 -1.5 3.2 5 Jul 43.0 17.2 high 250%
Wollogorang 30.2 -0.8 38.6 26 Sep 11.9 -1.6 3.3 13 Aug 65.4 13.4 highest 488%
Victoria (district 14F)
Lajamanu 29.1 -0.2 41.1 23 Sep 10.1 -1.9 1.2 20 Jun 0 21.3 lowest 0%
Timber Creek 32.3 -0.3 40.3 25 Sep 15.2 -1.8 5.5 22 Jun 0 18.8 lowest 0%
Victoria River Downs 31.2 -0.3 40.3 23 Sep 10.5 -3.6 2.0 3 Jul 0 16.8 lowest 0%
Barkly (district 15A)
Elliott 29.9 -1.1 39.4 26 Sep 12.3 -1.7 3.6 22 Jun 7.8 22.9 average 34%
Tennant Creek Airport 26.8 -0.3 38.7 23 Sep 13.8 -1.1 6.7 21 Jun 8.8 28.1 average 31%
Alice Springs (district 15B)
Alice Springs Airport 23.4 +0.9 38.8 22 Sep 4.0 -2.7 -5.2 7 Jul 3.8 64.9 v low 6%
Arltunga 22.2 -0.3 37.0 27 Sep 4.7 -1.6 -4.7 2 Aug 11.6 57.7 low 20%
Curtin Springs 23.7 +0.7 37.4 27 Sep 4.8 -1.8 -3.0 10 Jul 3.4 62.2 v low 5%
Jervois 24.3 -0.5 40.3 20 Sep 7.4 -0.6 -1.5 2 Aug 18.8 59.5 low 32%
Rabbit Flat 28.6 -0.1 40.7 23 Sep 8.1 -1.8 -2.0 5 Jul 0 31.9 v low 0%
Territory Grape Farm 24.8 -0.4 38.2 27 Sep 6.2 -1.8 -1.2 1 Aug 1.8 54.6 v low 3%
Walungurru 26.6   39.0 27 Sep 12.0   3.1 10 Jul 1.8 62.4 low 3%
Yulara Aero 23.6 +0.2 38.0 27 Sep 5.0 -2.3 -2.2 16 Jul 3.2 61.2 low 5%

Notes

A Seasonal 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 10 am on Monday 1 October 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