Tuesday, 3 May 2011 - Monthly Climate Summary for Northern Territory - Product code IDCKGC22R0
Northern Territory in April 2011: Early start to the dry season
April began with heavy rains and gusty storms across the Top End with several stations exceeding their previous record April rainfall within the first week of the month. The following weeks showed signs of the approaching dry season with cooler nights and fewer storms.
Heavy rainfall at Katherine
On the 2nd, Katherine Aviation museum measured 83.2 mm which was the wettest April day on record, passing the previous record of 64.0 mm set on the 25th in 1970. Katherine Aviation Museum then broke this record again on the 5th when they received 88.4 mm. The average April total rainfall at Katherine is only 38.4 mm.
Eastern Arnhem thunderstorms
On the 12th, a series of thunderstorms dumped heavy rain over the eastern Arnhem District. Rainfall totals from the event include 149.0 mm of rainfall at Gove Airport and 148.0 mm of rainfall at Yirrkala Tropical Gardens.
A taste of the dry season
The official start of the dry season is 1 May, but the end of April gave a taste of the dry season to Territorians in the Top End. On the 20th and 21st the minimum temperature at Darwin Airport dipped to below 20 °C for the first time this year. Another dry season indicator happened on the 18th when, for the first time this year, the dew point temperature in Darwin dropped below 15 °C.
A low pressure system over the Joseph Bonaparte Gulf on the 1st and 2nd pushed warm, moist, tropical air inland which produced heavy rainfall and gusty storms across the western Top End. As the low moved southwest the axis of the monsoon trough also moved south, bringing another burst of heavy rain to the area. This heavy rainfall during the first week of the month set new daily and monthly rainfall records for many stations across the western Top End.
The rest of the month showed signs of transition from wet season to dry season. Occasional isolated thunderstorms brought heavy rains to the Top End including Arnhem and coastal regions. As the month progressed these storms became less frequent.
The wettest single day was on the 12th when 149.0 mm fell at Gove Airport and 148.0 mm fell at Yirrkala Tropical Gardens. The next wettest day was at Mango Farm with 132.2 mm on the 1st.
The wettest overall was Yirrkala Tropical Gardens with 563.0 mm, followed by North East Island with 552.0 mm, and then Gove Airport with 491.8 mm.
Mean daily maximum temperatures were below average across the NT while the mean daily minimum temperatures were near average in the Top End and below average across the rest of the NT. Thick cloud cover in the beginning of the month kept daily maximum temperatures low while allowing minimum temperatures to stay relatively high across the Top End. The rest of the Territory, especially the Alice Springs District was strongly influenced by a series of high pressure systems in the Bight that pushed cool dry air into the Territory from the southeast.
The warmest on average was Jabiru Airport with 28.3 °C followed by Dum In Mirrie with 28.2 °C. The coolest on average was Arltunga with 18.1 °C, followed by Alice Springs Airport with 18.3 °C, and then Yulara Aero with 20.5 °C.
The hottest day was at Bradshaw with 35.6 °C on the 22nd, followed by McArthur River Mine with 35.5 °C on the 22nd, and Port Keats Aero also with 35.5 °C on the 26th.
The warmest days on average were at Jabiru Airport with 33.1 °C followed by McArthur River Mine and Bradshaw with with 33.0 °C, and then Port Keats Aero with 32.9 °C.
The coolest days on average were at Arltunga with 26.1 °C, followed by Alice Springs Airport with 27.0 °C, and then Kulgera with 27.5 °C.
The coldest day was at Rabbit Flat with 21.0 °C on the 4th, followed by Arltunga with 22.0 °C on the 11th, and then Tennant Creek Airport with 22.3 °C on the 2nd.Some sites, including Katherine Aviation Museum and Victoria River Downs, had their lowest April mean daily maximum temperature on record.
The coldest nights were at Arltunga with 2.0 °C on the 12th, 3.8 °C on the 25th, and 4.4 °C on the 19th.
The coolest nights on average were at Alice Springs Airport with 9.7 °C, followed by Arltunga with 10.1 °C, and then Kulgera with 10.8 °C.
The warmest nights on average were at North East Island with 25.4 °C followed by Centre Island with 24.3 °C and Warruwi also with 24.3 °C.
The warmest night was at Point Stuart with 27.2 °C on the 8th.Tennant Creek Airport, Centre Island and Lajamanu had their lowest April mean daily minimum temperature on record.
The strongest wind gusts were at Point Fawcett and at Walungurru which both measured 65 km/h on the 2nd. The next strongest wind gusts were Walungurru with 63 km/h on the 1st and Centre Island which also measured a gust of 63 km/h on the 2nd.
|Extremes in April 2011|
|Hottest day||35.6 °C at Bradshaw on the 22nd|
|Warmest days on average||
33.1 °C at Jabiru Airport
|Coolest days on average||
26.1 °C at Arltunga
21.0 °C at Rabbit Flat on the 4th
2.0 °C at Arltunga on the 12th
|Coolest nights on average||
9.7 °C at Alice Springs Airport
|Warmest nights on average|| 25.4 °C at North East Island
|Warmest night||27.2 °C at Point Stuart on the 8th|
|Warmest on average overall|| 28.2 °C at Jabiru Airport
|Coolest on average overall||
18.1 °C at Arltunga
565.0 mm at Yirrkala Tropical Gardens
|Wettest day||149.0 mm at Gove Airport on the 12th|
|Highest wind gust||
65 km/h at Point Fawcett on the 2nd|
65 km/h at Walungurru on the 2nd
|Record highest April daily rainfall|
Highest daily rainfall
in April 2011 (mm)
|Katherine Aviation Museum||88.4||on the 5th||64.0||on the 25th in 1970||35|
|Hidden Valley||61.5||on the 3rd||32.8||on the 27th in 2006||26|
|Gorrie||107.0||on the 6th||55.6||on the 9th in 1996||23|
|Wagait Beach||114.6||on the 1st||90.0||on the 5th in 2006||21|
|Walker Creek||107.6||on the 1st||84.0||on the 15th in 2010||17|
|Record highest total April rainfall|
for April 2011 (mm)
|Katherine Aviation Museum||227.8||212.6||in 2006||35||38.4|
|Hidden Valley||135.7||99.6||in 2006||28||17.5|
|Mango Farm||356.8||308.6||in 2006||30||60.0|
|Record lowest April mean daily maximum temperature|
Mean daily maximum
for April 2011 (°C)
|Victoria River Downs||31.5||32.0||in 1983||42||34.5|
|Daly Waters||30.7||30.9||in 1963||41||33.9|
|Centre Island||30.1||= 30.1||in 1999||36||32.1|
|Timber Creek||32.7||32.8||in 1985||30||35.2|
|Katherine Aviation Museum||31.4||31.6||in 2006||24||34.2|
|Kidman Springs||32.0||33.1||in 2006||15||35.5|
|Delamere Weapons Range||31.0||31.6||in 2006||13||34.3|
|Rabbit Flat||30.5||31.0||in 2000||13||34.2|
|Record lowest April mean daily minimum temperature|
Mean daily minimum
for April 2011 (°C)
|Tennant Creek Airport||17.5||18.2||in 1971||41||20.4|
|Centre Island||24.3||24.5||in 2008||36||25.3|
|Summary statistics for April 2011|
|Darwin-Daly (district 14GA)|
|Batchelor Aero||31.9||-2.0||33.8||22nd||22.1||+0.6||15.1||20th||353.8||88.7||v high||399%|
|Delamere Weapons Range||31.0||-3.3||33.3||8th||20.3||-0.7||15.7||30th||54.6||18.8||v high||290%|
|Douglas River||32.4||-2.3||34.1||10th||21.0||+0.7||13.9||20th||209.6||47.2||v high||444%|
|Dum In Mirrie||32.3||-0.6||34.8||23rd||23.7||-0.6||19.3||20th||240.8||96.9||high||249%|
|Jabiru Airport||33.1||-1.4||35.3||22nd||23.2||-0.3||19.7||28th||196.4||76.5||v high||257%|
|Katherine Aviation Museum||31.4||-2.8||33.1||22nd||20.1||-0.6||13.7||20th||227.8||38.4||highest||593%|
|Pine Creek Council||31.4||-2.6||33.4||22nd||21.4||-0.7||17.2||19th||295.6||69.4||v high||426%|
|Point Fawcett||31.1||-1.1||33.0||23rd||22.6||-1.0||16.5||21st||339.8||118.0||v high||288%|
|Port Keats Aero||32.9||35.5||26th||22.5||15.3||20th||242.4|
|Arnhem (district 14BC)|
|Groote Eylandt Airport||31.3||-1.1||33.3||22nd||21.4||-0.1||16.1||19th||268.4||162.1||high||166%|
|North East Island||30.3||31.9||25th||25.4||23.4||5th||552.0||173.7||high||318%|
|Roper-Mcarthur (district 14DE)|
|Centre Island||30.1||-2.0||32.5||22nd||24.3||-1.0||21.9||19th||233.8||85.4||v high||274%|
|Daly Waters||30.7||-3.2||33.1||8th||17.9||-1.8||11.7||20th||107.6||20.7||v high||520%|
|McArthur River Mine||33.0||-1.8||35.5||22nd||20.1||-0.4||14.9||19th||79.4||28.1||v high||283%|
|Victoria (district 14F)|
|Kidman Springs||32.0||-3.5||34.7||15th||19.3||-1.3||12.4||19th||64.3||23.1||v high||278%|
|Victoria River Downs||31.5||-3.0||35.8||26th||18.6||-1.1||11.9||19th||97.4||22.5||v high||433%|
|Barkly (district 15A)|
|Brunette Downs||30.0||-3.6||33.1||9th||17.2||-2.0||13.0||18th||37.4||14.5||v high||258%|
|Tennant Creek Airport||28.7||-3.0||32.1||14th||17.5||-2.9||13.2||18th||20.2||15.4||high||131%|
|Alice Springs (district 15B)|
|Alice Springs Airport||27.0||-1.2||31.6||14th||9.7||-2.9||5.1||12th||0||16.3||lowest||0%|
|Territory Grape Farm||29.0||-1.8||33.2||14th||12.2||-2.4||7.2||13th||0||17.9||lowest||0%|
|Offshore Islands (district 200)|
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 12 pm on Tuesday 3 May 2011. 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
the years 1800 to 2009.
They are not shown for sites with less than 10 years of record in that time, 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.