Tuesday, 1 October 2013 - Seasonal Climate Summary for Northern Territory - Product code IDCKGC22R0

Northern Territory in May to September 2013: Hottest dry season on record

• Northern Territory Records:
  • Highest May to September mean daily maximum temperature
  • Highest May to September mean daily temperature
  • Third highest May to September mean daily minimum temperature
• Temperatures:
  • Timber Creek sets new August and winter NT record with 39.7 °C on the 20th
  • Alice Springs Airport ties hottest May to September period on record
• Rainfall:
  • Four cloudband events in May for Alice Springs District
  • Top End rainfall in May sets daily and monthly records
• Extremes:
  • Hottest day was 41.3 °C at Bradshaw on 27 Sep
  • Coldest Night was -3.4 °C at Arltunga on 22 Jun
  • Highest daily rainfall was 101.4 mm at Batchelor Aero on 24 May

Extremes Maps Records Summaries Important notes the top

Bushfires

The dry season is also bushfire season, in the NT. On 21 June the Bureau of Meteorology issued the first fire weather warning for the northern fire season. The warning area covered the greater Darwin and rural area and the Vernon area (Batchelor and Litchfield). Bushfire NT issued their first fire ban on the same day.

Although wet season rainfall was generally below average for northern Australia, the short bursts of heavy rain followed by several weeks of sunny and humid weather was ideal for vegetative growth; thus the fuel load was quite high across the Top End as the northern fire season began. By the end of June the weather had been dry enough for grasses to dry and the fire danger to increase.

Several fires burned across the Top End in the middle of the dry season (July and August). In July, the Bureau of Meteorology issued a fire weather warning on 16 days. An early July fire near Noonamah lofted smoke over the greater Darwin area and affected visibility along the Stuart Highway. August began with several bushfires burning across the Top End. At least three fires were active on the Tiwi Islands within the first week of August and a large fire burnt near the Arnhem Highway. Smoke and haze was a dominant feature of the atmosphere around Darwin early during this time in the dry season.

Timber Creek sets new NT temperature record

On August 20th, Timber Creek reached a maximum temperature of 39.7 °C. This is half a degree hotter than the previous Northern Territory record highest August (and winter) daily maximum temperate of 39.2 °C measured at Mango Farm on 25 August 1998. This new record at Timber Creek also tied the second hottest August day on record for all of Australia (39.7 °C at Wyndham Aero, WA, on 31 August 2009).

Cloudbands and Alice Springs Rainfall

In May, the sea surface temperature (SST) off the northwest coast of Australia were very much above average, with some areas nearly two degrees above the long-term average and exceeding the previous May SST temperature record. The temperature of the sea surface is an important weather ‘driver’ for the NT. Warm SSTs off the northwest coast can provide tropical moisture to cloud bands that sweep across the central part of the continent. In May the Alice Springs District saw 4 cloud band events providing ample rainfall to the region. Alice Springs Airport measured 42.6 mm in May, this is more than double their long-term average and their wettest May in 9 years. Across the whole Alice Springs District, every site measured above average rainfall with some sites recording their wettest May on record. To the North of Alice Springs, Rabbit Flat (a WMO climate reference station) and The Granites both saw their wettest May on record with 82.0 mm and 93.0 mm respectively.

In June, two significant cloudbands formed over northern WA and brought rainfall to the far southwest corner of the NT. Another cloudband event in July contributed to above average rainfall at Yulara and Alice Springs.

Rainfall

We don't often think about rainfall in the dry season. As the name suggest, the season is inherently dry. However, the NT does occasionally see rain between May and September. This season most rain fell in May. May is a transition month, which means that the air mass over the Top End has to change from warm and humid to cool and dry. The mechanism for change is related to southern winter conditions by the presence of strong high pressure systems. These systems bring cool, dry southeasterly winds from higher latitudes and dry season conditions to the Top End.

In May 2013 a southeasterly wind change reached the north coast on the 24th. As the incumbent southeasterlies met the warm humid airmass over the Top End, a series of showers were triggered which broke several rainfall records both for the month of May and for the dry season. Showers are always a possibility ahead of a southeasterly wind change as the cold dry air undercuts the warm humid air and lifts it to form cloud. What made this event distinct was the depth of moisture in the atmosphere. The warm SSTs off the northwest coast, coupled with prevailing easterly winds during the early half of May contributed to a deep layer of moisture and a good environment for showers on the 24th. Thus, the wettest single day in the NT this dry season was at Batchelor Aero with 101.4 mm on 24 May. It is unusual for a location in the western Top End to measure more than 100 mm in a dry season month, it is even more unusual for over 100 mm to fall in one day. Several other sites saw their highest dry season daily rainfall on record from the May 24th event including Litchfield with 91.4 mm, Territory Wildlife Park with 61.0 mm and Darwin River Ridge with 55.8 mm.

In addition to the Top End rainfall, May was an exceptionally wet month in the Alice Springs District as well. Four precipitating cloudbands moved across the Alice Sprigs District in May and Rabbit Flat and the Granites saw their wettest May on record. Cloudbands also affected the region in June and July.

The wettest overall this dry season was Batchelor Aero with 181.6 mm, followed by North East Island with 152.8 mm, and then McCluer Island with 138.6 mm.

Temperature: Hottest dry season on record

In terms of mean temperature (average of daily maximum and daily minimum temperature), the NT sweltered through the hottest dry season on record. The mean temperature for the NT this dry season was 28.1 °C, which is 1.9 °C higher than the long-term average (26.2 °C). This passes the previous mean temperature record of 27.8 °C set in 1998.

There were several potential contributing factors to the high temperatures this season. One possible cause was a negative Indian Ocean Dipole (IOD). When the IOD is negative the ocean temperatures surrounding northern and northwestern Australia tend to increase. Not only does this provide extra heat into the air over coastal regions, it may also change the weather patterns over the continent allowing for stronger easterly winds over the Top End. A negative IOD pattern (with IOD index less than -0.4) was in place in May, June, July and early August and most likely contributed to the higher than normal temperatures in the early dry season.

Another possible contributing cause to the high temperatures was that this season saw fewer/weaker high pressure systems moving across the Great Australian Bight. These high pressure systems are essential in producing an airmass change over central and northern Australia. As a high pressure moves across the Bight it pushes cool, dry, continental air north sometimes reaching the north coast. These southerly surges usually occur three to four times each month in the dry season and bring lower temperatures and lower humidity. Where fewer of these southerly surges occurred northern Australia (and to some degree central Australia, too) remained warmer than normal and more humid for most of August.

Across the NT this season, the warmest on average was Cape Don with 28.2 °C, followed by Jabiru Airport with 27.9 °C, and then Cape Wessel with 27.4 °C. The coolest on average was Arltunga with 16.2 °C, followed by Kulgera with 16.5 °C, and then Yulara Aero with 16.6 °C.

Maximum temperature: highest on record

When averaged across the NT the mean daily maximum temperature this season was 35.3 °C, which is 2 °C above average and the highest mean daily maximum temperature on record for the NT during the dry season. Several sites, including VRD and Tennant Creek Airport, had their highest May to September temperature on record. With a mean daily maximum temperature of 24.9 °C, Alice Springs Airport tied their highest May to September mean daily maximum temperature on record. Tennant Creek Airport, Rabbit Flat, and VRD were also among the sites to set new dry season daily maximum temperature temperature records.

Bradshaw saw the three hottest days in the NT this month with 41.3 °C on the 27th, followed by 41.2 °C on the 20th, and then 41.1 °C on the 17th. It is not a surprise then that the warmest days on average were at Bradshaw with an average monthly maximum temperature of 34.9 °C, followed by Douglas River with 34.8 °C, and then Jabiru Airport and Middle Point both with 34.3 °C.

The coldest day (lowest daily maximum temperature) was at Kulgera with 9.8 °C on 19 Jun and then again on 9 Jul, followed by Curtin Springs with 10.5 °C on 9 Jul, and then Arltunga with 10.8 °C on 9 Jul. The coolest days on average were at Kulgera with 23.5 °C, followed by Arltunga with 24.4 °C,and then Curtin Springs with 24.8 °C.

Minimum temperature: 3rd highest on record

With an NT average daily minimum temperature of 20.9 °C, this dry season ranked as the third warmest on record, for minimum temperatures. The long-term average is 19 °C and the record warmest was 21 °C set in May to September 1998.

The minimum temperature at Darwin Airport dropped below 20 °C only 38 times, this season, this is 13 times fewer than average and a stark difference to the last two dry seasons which saw 94 nights below 20 in 2011 and 86 nights in 2012. Darwin had experienced only four nights below 20 °C up to 30 June, this year. There was a run of 20 nights below 20 °C between 24 July and 13 August. 2 September was the last night this season to see the temperature drop below 20 °C.

The coldest nights anywhere in the NT between May and September this year was at Arltunga with -3.4 °C on 22 Jun, followed -2.8 °C on 23 Jun, and then -2.7 °C on 21 Jun. The coolest nights on average were at Arltunga with 8.1 °C, followed by Yulara Aero with 8.4 °C, and then Alice Springs Airport with 8.5 °C.

The warmest nights across the NT this dry season was at Cape Don with 28.2 °C on 3 May, followed by North East Island with 28.1 °C on 2 May, and then McCluer Island with 27.8 °C on 7 May. The warmest nights on average were at Cape Don, Cape Wessel and McCluer Island all with a seasonal mean daily minimum temperature of 24.5 °C, followed by North East Island with 23.7 °C, and then Warruwi with 23.3 °C.

There were a few new minimum temperature records set this dry season. Kulgera and Ngayawili were among the sites to see their warmest May to September night (highest daily minimum temperature) on record. Tennant Creek Airport had their highest May to September mean daily minimum temperature on record.

Wind

The strongest wind gust was at Cape Wessel with 78 km/h on 3 May, followed by McCluer Island with 72 km/h on 4 May, Centre Island with 72 km/h on 25 May, and McCluer Island again with 72 km/h on 7 Sep.

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Extremes in May to September 2013
Hottest day	41.3 °C at Bradshaw on 27 Sep
Warmest days on average	34.9 °C at Bradshaw
Coolest days on average	23.5 °C at Kulgera
Coldest day	9.8 °C at Kulgera on 19 Jun 9.8 °C at Kulgera on 9 Jul
Coldest night	-3.4 °C at Arltunga on 22 Jun
Coolest nights on average	8.1 °C at Arltunga
Warmest nights on average	24.5 °C at Cape Don 24.5 °C at Cape Wessel 24.5 °C at McCluer Island
Warmest night	28.2 °C at Cape Don on 3 May
Warmest on average overall	28.2 °C at Cape Don
Coolest on average overall	16.2 °C at Arltunga
Wettest overall	181.6 mm at Batchelor Aero
Wettest day	101.4 mm at Batchelor Aero on 24 May
Highest wind gust	78 km/h at Cape Wessel on 3 May

Extremes Maps Records Summaries Important notes the top

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Maps

Month by month
Rainfall rank	Maximum temperature rank	Minimum temperature rank
May
June
July
August
September
Rainfall rank	Maximum temperature rank	Minimum temperature rank

Extremes Maps Records Summaries Important notes the top

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Record highest May to September daily rainfall
	Highest daily rainfall in May to September 2013 (mm)		Previous wettest for May to September		Years of record
Middle Point Rangers	91.4	on 24 May	74.0	on 18 May 1987	46
Litchfield	55.4	on 24 May	51.4	on 18 Sep 1984	30
Glen Helen Lodge	38.0	on 12 May	34.6	on 8 Jul 2005	22
Territory Wildlife Park	61.0	on 24 May	39.0	on 20 May 2004	21
Batchelor Aero	101.4	on 24 May	57.6	on 19 May 2007	20
Point Fawcett	61.0	on 23 May	58.0	on 13 May 1998	19
Bonalbo	24.0	on 23 May	21.5	on 28 May 2004	18
Cooinda Aerodrome	97.8	on 18 May	24.4	on 10 May 2012	18
Ludmilla	61.8	on 24 May	39.2	on 30 Sep 2012	18
Wandie Creek	64.6	on 18 May	55.0	on 30 Sep 1987	18
Groote Eylandt Airport	61.8	on 10 May	41.0	on 19 May 2004	15
Middle Point	44.6	on 24 May	42.0	on 14 Sep 2002	13
Darwin River Ridge	67.4	on 24 May	61.6	on 23 May 2010	12
Bulman	55.8	on 23 May	45.0	on 14 May 2007	11
Maningrida Aero	39.4	on 6 May	27.0	on 25 May 2012	10
Neutral Junction	34.0	on 13 May	32.2	on 17 May 2007	10

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Record highest total May to September rainfall
	Total rainfall for May to September 2013 (mm)	Previous wettest for May to September		Years of record	Average for May to September
Batchelor Aero	181.6	87.4	in 2010	18	37.5
Maningrida Aero	91.4	78.4	in 2010	10	35.8

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Record highest May to September temperature
	Highest temperature in May to September 2013 (°C)		Previous warmest for May to September		Years of record	Average for May to September
Brunette Downs	40.4	on 29 Sep	40.3	on 26 Sep 1997	50	29.3
Victoria River Downs	40.7	on 27 Sep	40.4	on 17 Sep 1971	49	31.5
Tennant Creek Airport	39.0	on 24 Sep	38.9	on 27 Sep 1997	45	27.1
Pirlangimpi	38.0	on 23 Sep	37.2	on 26 Sep 2010	31	31.9
Territory Grape Farm	38.8	on 25 Sep	38.2	on 27 Sep 2012	22	25.2
Point Fawcett	35.4	on 16 May	35.2	on 22 Sep 2005	16	30.6
Middle Point	40.0	on 19 Sep	39.4	on 19 Sep 2008	13	33.6

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Record highest May to September mean daily maximum temperature
	Mean daily maximum temperature for May to September 2013 (°C)	Previous warmest for May to September		Years of record	Average for May to September
Alice Springs Airport	24.9	= 24.9	in 2002	71	22.5
Brunette Downs	31.0	30.6	in 2003	46	29.3
Victoria River Downs	33.8	33.1	in 2009	46	31.5
Tennant Creek Airport	29.1	28.7	in 2009	43	27.1
Centre Island	29.1	= 29.1	in 1988	37	28.1
Wave Hill	32.6	= 32.6	in 1992	37	30.7
McArthur River Mine	33.2	= 33.2	in 1988	32	31.8
Timber Creek	34.1	33.9	in 1998	32	32.6
Pirlangimpi	33.5	33.2	in 1998	29	31.9
Wollogorang	32.3	32.1	in 1988	28	31.0
Douglas River	34.8	34.6	in 1998	21	33.1
Rabbit Flat	30.3	30.1	in 1999	16	28.7
Groote Eylandt Airport	30.7	= 30.7	in 2009	14	30.2
Point Fawcett	31.8	31.6	in 2005	14	30.6
Arltunga	24.4	24.2	in 2002	12	22.5
Bradshaw	34.9	34.3	in 2009	11	33.3
Middle Point	34.3	= 34.3	in 2003	11	33.6

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Record highest May to September daily minimum temperature
	Highest daily minimum temperature in May to September 2013 (°C)		Previous warmest for May to September		Years of record	Average for May to September
Kulgera	22.7	on 4 Sep	21.7	on 28 Sep 2005	34	7.4
Delamere Weapons Range	27.1	on 22 Sep	26.0	on 20 Sep 2008	17	16.8
McCluer Island	27.8	on 7 May	27.5	on 27 May 2004	14	23.8
Ngayawili	25.8	on 17 May	25.4	on 16 May 2010	14	20.3

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Record highest May to September mean daily minimum temperature
	Mean daily minimum temperature for May to September 2013 (°C)	Previous warmest for May to September		Years of record	Average for May to September
Jervois	10.9	10.7	in 2009	44	8.0
Tennant Creek Airport	16.5	16.3	in 1996	43	14.8
Kulgera	9.7	9.4	in 1996	31	7.4
Territory Grape Farm	10.5	9.6	in 2009	17	7.9
Arltunga	8.1	8.0	in 2009	12	6.2
McCluer Island	24.5	= 24.5	in 2003	11	23.8

Extremes Maps Records Summaries Important notes the top

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Summary statistics for dry season 2013
	Maximum temperatures for May to September (°C)				Minimum temperatures for May to September (°C)				Rainfall for May to September (millimetres)
	Mean for May to September 2013	Diff from average	Highest for May to September 2013		Mean for May to September 2013	Diff from average	Lowest for May to September 2013		Total for May to September 2013	Average for May to September	Rank of May to September 2013	Fraction of May to September average
Darwin-Daly (district 14GA)
Black Point	31.0	+0.5	34.3	23 Sep	22.8	+0.8	17.8	1 Aug	10.6	45.8	average	23%
Bradshaw	34.9	+1.6	41.3	27 Sep	19.4	+2.0	7.9	3 Jul	0.6	29.3	low	2%
Cape Don	31.8		34.9	6 May	24.5		20.5	11 Aug	20.4	43.6	average	47%
Central Arnhem Plateau	31.4		37.7	24 Sep	18.1		9.7	25 Jul	49.2
Croker Island Airport	30.8		35.1	23 Sep	22.9		19.0	9 Aug	25.8
Darwin Airport	32.3	+0.9	35.2	2 May	21.6	+0.7	15.8	8 Aug	35.0	44.8	average	78%
Delamere Weapons Range	32.6	+1.2	39.4	20 Sep	18.2	+1.4	9.5	3 Jul	0	12.3	lowest	0%
Douglas River	34.8	+1.7	39.1	20 Sep	16.8	+1.7	7.5	8 Aug	6.8	21.4	average	32%
Dum In Mirrie	31.8	+0.9	36.9	3 May	21.3	+1.0	12.0	25 Jul	47.6	35.2	high	135%
Jabiru Airport	34.3	+0.9	38.8	24 Sep	21.6	+1.6	15.1	2 Jul	76.2	25.5	high	299%
Katherine Country Club	33.4		39.4	20 Sep	17.2		5.2	26 Jul	0.1
Mango Farm	33.8	+0.7	39.3	17 Sep	17.5	+0.7	8.0	8 Aug	38.2	22.1	high	173%
McCluer Island	28.5	+0.2	31.9	22 Sep	24.5	+0.7	20.8	2 Jul	138.6	68.0	high	204%
Middle Point	34.3	+0.7	40.0	19 Sep	17.5	+1.1	7.7	5 Aug	77.2	41.7	high	185%
Murganella Airstrip			38.9	22 Sep	19.6		10.9	4 Aug	22.0
Pirlangimpi	33.5	+1.6	38.0	23 Sep	21.2	+1.4	14.1	26 Jul	14.8	63.6	low	23%
Point Fawcett	31.8	+1.2	35.4	16 May	20.0	+0.3	13.3	7 Aug	115.2	56.8	high	203%
Point Stuart	32.0		35.0	22 Sep	20.6		12.3	4 Aug	39.4	20.8	high	189%
Tindal RAAF	33.2	+1.3	38.9	23 Sep	16.6	+0.5	7.0	26 Jul	11.0	14.3	high	77%
Arnhem (district 14BC)
Cape Wessel	30.4		32.8	1 May	24.5		20.4	23 Sep
Gove Airport	29.7	+0.8	34.2	21 Sep	21.1	+0.5	11.5	8 Aug	128.0	151.3	average	85%
Groote Eylandt Airport	30.7	+0.5	36.1	13 Sep	17.9	+1.3	9.4	9 Aug	81.2	41.3	high	197%
Maningrida Aero	31.4		37.7	22 Sep	20.4		12.7	9 Aug	91.4	35.8	highest	255%
Milingimbi	31.2		34.6	21 Sep	21.1		14.9	7 Aug	52.0	43.8	average	119%
Ngayawili	30.8	+0.4	33.1	18 May	21.3	+1.0	15.0	9 Aug	15.2	47.4	low	32%
North East Island	29.1		32.9	1 May	23.7		19.0	10 Aug	152.8	45.1	v high	339%
Warruwi	30.3	+0.6	37.0	22 Sep	23.3	+0.8	18.2	8 Aug	50.6	21.0	high	241%
Roper-Mcarthur (district 14DE)
Centre Island	29.1	+1.0	35.2	13 Sep	21.3	+0.9	15.8	2 Jul
Daly Waters	33.1	+2.3	39.2	23 Sep	14.6	+0.4	3.5	26 Jul	0.6	14.5	average	4%
McArthur River Mine	33.2	+1.4	39.7	26 Sep	16.5	+2.1	6.5	25 Jul	1.2	16.4	average	7%
Ngukurr	33.0		40.0	20 Sep	17.3		7.5	9 Aug	11.0
Wollogorang	32.3	+1.3	39.1	18 Sep	14.1	+0.6	5.4	26 Jul	6.9	13.2	average	52%
Victoria (district 14F)
Timber Creek	34.1	+1.5	41.0	27 Sep	17.5	+0.6	7.4	3 Jul	2.4	18.3	average	13%
Victoria River Downs	33.8	+2.3	40.7	27 Sep	16.0	+2.0	4.6	26 Jul
Wave Hill	32.6	+1.9	40.4	24 Sep	15.7	+2.3	3.3	26 Jul	3.6	27.0	average	13%
Barkly (district 15A)
Brunette Downs	31.0	+1.7	40.4	29 Sep	14.9	+1.7	6.4	1 Jul	16.0	26.3	average	61%
Tennant Creek Airport	29.1	+2.0	39.0	24 Sep	16.5	+1.7	7.0	23 Jun	24.1	28.1	average	86%
Alice Springs (district 15B)
Alice Springs Airport	24.9	+2.4	38.1	25 Sep	8.5	+1.8	-1.1	25 Jul	91.2	65.3	high	140%
Arltunga	24.4	+1.9	37.3	25 Sep	8.1	+1.9	-3.4	22 Jun	63.8	57.8	average	110%
Curtin Springs	24.8	+1.8	37.5	22 Sep	8.6	+2.0	-0.5	23 Jul	75.5	62.4	average	121%
Jervois			40.4	24 Sep	10.9	+2.9	1.1	22 Jun	62.4	59.6	average	105%
Kulgera	23.5	+1.6	36.0	23 Sep	9.7	+2.3	0.1	23 Jul	75.2	63.5	high	118%
Rabbit Flat	30.3	+1.6	40.1	24 Sep	11.3	+1.5	0.7	26 Jul	73.4	34.3	high	214%
Territory Grape Farm	26.9	+1.7	38.8	25 Sep	10.5	+2.6	-0.3	25 Jul	48.0	54.4	average	88%
Walungurru	27.2		38.0	22 Sep	14.6		6.9	6 Aug	65.4	62.7	average	104%
Yulara Aero	24.9	+1.5	37.3	22 Sep	8.4	+1.2	-0.9	25 Jul	65.2	61.4	average	106%

Extremes Maps Records Summaries Important notes the top

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