Thursday, 1 May 2014 - Seasonal Climate Summary for Northern Territory - Product code IDCKGC12R0

Northern Territory in October to April 2013-14: high rainfall for central NT

Summary

Most Top End locations ended the season near the long-term average, having seen some very wet and some very dry periods throughout the season. The Roper-Mcarthur, Barkly and Victoria River Downs rainfall districts ended the season with very much above average rainfall totals.

A typical buildup period was followed by one of the earliest monsoon onsets on record at Darwin. The last week of November saw an active monsoon trough over the Top End and included the impact of tropical cyclone Alessia. Early January saw high temperatures and a few January temperature records set across the Top End. Around 13 January another active monsoon period began which lasted nearly five weeks and included ex-tropical cyclone Fletcher and two other tropical lows which moved across the Territory. March was quite dry across the Top End. The wet season ended with a series of small rainfall events that continued until the end of April.

• Early monsoon onset in November
• Active monsoon in January and February
• Low rainfall in March
• One tropical cyclones make landfall on NT
  • tropical cyclone Alessia
    • 24 November 2013

Extremes Maps Records Summaries Important notes the top

Seasonal detail

October heralds the beginning of the wet season across northern Australia, however, rain gauges across most of the NT were left empty. Areas across the southern Darwin - Daly, Roper McArthur and Barkly received below average rainfall for the month while Victoria River and eastern Alice Springs Districts were very much below average.

Throughout October, rain fell over Darwin Airport on 10 days, 3 more rain days that the average, yet it only manage to received 14.6 mm of rain which is well below the monthly average of 71.0 mm. In the south, Uluru just managed 0.4 mm of rain (average is 26.7 mm) and Alice Springs 0.6 (average is 21.7 mm). Only the Tiwi Islands, Darwin's northern suburbs, and the far southeastern corner of the Arnhem Land managed to get above average rainfall for the month.

On the 4 and 5 November an outbreak of thunderstorms over the western Top End set a number of November daily rainfall records. Darwin Airport received 104.8 mm in the 24 hours to 9am on the 5th. Palmerston set a new November record with 78.2 mm. The highest falls on the day was 156.8 mm at Darwin Botanic Gardens, also a new November record for this site.

On 20 November a tropical low pressure system formed within a tropical trough over the eastern Indian Ocean south of Java. The low moved east and intensified reaching tropical cyclone strength on the 22nd off the northwest shelf and was named tropical cyclone Alessia. The storm skirted the Kimberley coastline and then made landfall on the western Top End near the mouth of the Daly River at around 18:30 local time on the 24th. After making landfall, Alessia weakened to a tropical low and moved across the Top End producing large rainfall across the region. Ex-tropical cyclone Alessia moved into the Gulf of Carpentaria on the 26th. The warm waters of the Gulf provided energy for Alessia to intensify again to a tropical cyclone near Centre Island on the 27th. Tropical Cyclone Alessia made landfall again about 70 km west of the NT/QLD border, and remained in the region as a tropical low until the end November.

December began with the Top End under monsoon break conditions with occasional afternoon thunderstorms. Toward the end of the month the monsoon reformed off the north coast and moved south over the continent on the 25th and the 26th. However, the northwest coast was the only region that saw much rainfall from this monsoon event and rainfall totals were relatively small.

January started with very much above average temperatures at Darwin Airport. On the 6th Darwin set a new January daily maximum temperature record when the mercury rose to 36.0 °C only to break this record again on the next day with 36.1 °C. (The previous hottest January day was 35.6 °C on 4 January 1985). The high temperature on the 7th was measured coincident with nearly 70% relative humidity. A few days later a monsoon trough began to organise to the north of Darwin and the high temperatures were replaced by thick cloud and continual rainfall. On the 14 January, the temperature at Darwin Airport stayed around 25 °C for most of the day (but rose to 28 °C briefly overnight, which was recorded as the maximum temperature for the day), a stark contrast to the record high temperatures experienced only one week earlier.

This active and prolonged monsoonal period set in around the 10th of January at Darwin and across the rest of the Top End shortly afterward. On 10 January a low pressure system formed within the monsoon trough off the northeast coast of the Top End and moved west causing monsoonal showers and squally storms along the north coast. The centre of the low moved over land near the Coburg Peninsula on the 14th and then moved across the western Top End on the 14th and 15th. The low continued inland along the NT/WA boarder producing heavy rainfall over the Victoria River District and northern Alice Springs District. The monsoon produced continual, and at times heavy, rainfall over the Top End for most of January and February. Over the course of almost five weeks three tropical low pressure systems moved across the Territory include ex-tropical cyclone Fletcher which moved over the Barkly region. The monsoon activity waned toward the end of February.

In contrast to the the previous two months, March 2014 was among the driest on record. Many locations in the Alice Springs District did not measure any rainfall in March. Several sites, including Adelaide River, Palmerston (Yarrawonga) and Yulara had their lowest total March rainfall on record. Darwin Airport, with only 92.2 mm for the month, had its driest March in 36 years and the second driest March on record.

There were two noteworthy rainfall events in the Northern Territory in April. The first occurred from 7 to 10 April when a northwest cloudband event pulled moist tropical air across the southwest edge of the Territory. Generally across the western Alice Springs District and southern Victoria River District, April was the wettest in 14 years. Another noteworthy rainfall event occurred over the Gulf of Carpentaria and eastern Arnhem land from 23 to 25 April when a small tropical trough developed over the region. Most of the convection stayed over the ocean, but several locations along the Top End's east coast set new April rainfall records from the event.

Most Top End locations ended the season near the long-term average, having seen some very wet and some very dry periods throughout the season.

The Roper-Mcarthur, Barkly and Victoria River Downs rainfall districts ended the season with very much above average rainfall totals, most of which came from the transit of three low pressure systems during the season. However no new total rainfall records were set for the season.

The western Alice Springs district, including the Tanami Desert region, experienced above average rainfall while the eastern Alice Springs district saw less rainfall than usual for the period.

Extremes Maps Records Summaries Important notes the top

Maps
	Observed	Anomaly	Decile rank
Total rainfall

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Month by month
Rainfall rank	Maximum temperature rank	Minimum temperature rank
October 2012: A dry start to the wet
November 2013: Early monsoon onset
December 2013: A return to normal temperatures
January 2014: A hot start to an overall cool, wet month
February 2014: Cool with above-average rainfall
March 2014: A taste of the dry season in the north
April 2014: Rainfall in the Alice
Rainfall rank	Maximum temperature rank	Minimum temperature rank

Extremes Maps Records Summaries Important notes the top

Extremes Maps Records Summaries Important notes the top