The Bureau of Meteorology said that ex-tropical cyclone Tiffany would move across the base of the Top End on Wednesday and overnight and was expected to be west of Katherine by Thursday.

The heaviest rain - expected on the southern and western flanks of the system - could lead to dangerous and life-threatening flash flooding.

Locations which may be affected include Katherine, Wadeye, Nauiyu, Adelaide River, Mataranka, Pine Creek, Ngukurr, Timber Creek, Bulman, Barunga, Beswick and Numbulwar.

OTHER CYCLONE NEWS:

The BoM warned that heavy rainfall was expected across parts of the Arnhem and Carpentaria districts Wednesday and overnight and extending into parts of the Daly and Gregory Districts on Thursday.

There was a flood watch in place for many Top End river catchments.

The BoM said that damaging wind gusts up to 100 kmh were expected across parts the Arnhem and Carpentaria districts, contracting into the Daly and Gregory districts on Thursday.

Thunderstorms near the tropical low could generate locally destructive wind gusts up of up to 130km/h.

Wind gusts with thunderstorms brought down trees at Mataranka and Jilkminggan earlier this morning.

The BoM said that severe thunderstorms were also possible across areas of the Top End,

Updated: 1.30pm, Wednesday: Ex-tropical Cyclone Tiffany crossed the Territory coast this morning and is now located over land west of Ngukurr.

All warnings for the cyclone have now been cancelled along with a severe thunderstorm warning for areas around Katherine and to the north west.

The BoM said the system was now a tropical low with sustained winds near the centre of 55 kmh per hour and gusts up to 95 kmh.

OTHER CYCLONE NEWS

The system is about 35 km west northwest of Ngukurr and 235 kilometres east of Katherine moving at 29 km/h.

UPDATED: 10:30am, Wednesday: Tropical cyclone Tiffany is currently crossing the coast near Port Roper as a category one system.

A warning zone is in place from Alyangula to Port McArthur, including Numbulwar, Ngukurr and Port Roper. The alert for Groote Eylandt has been cancelled.

The system has picked up speed and is now moving at 27kmh.

A severe thunderstorm warning area has been extended to include Katherine alongside Darwin, Palmerston, Nauiyu, Batchelor, Adelaide River, Pine Creek, Dundee Beach and Peppimenarti.

Lines of severe thunderstorms are expected to develop and move from north to south across the western Top End on the periphery of the cyclone's path.

Once the system weakens below tropical cyclone intensity, strong gusts and heavy rainfall remain possible over areas close to the system track as it moves further inland.

The Bureau of Meteorology said gales with gusts to 100 kmh were likely near Port Roper and Nathan River and could extend to Ngukurr around midday as the cyclone moves inland before weakening.

The Numbulwar school shelter remains open, although Groote Eylandt residents have been told they can leave shelters when safe to do so.

People were warned to be careful around debris, fallen power lines and flooded roads.

UPDATED, 9am, Wednesday: Tropical Cyclone Tiffany has weakened slightly and is now unlikely to reach category two before making landfall near Port Roper later on Wednesday.

A warning zone from Alyangula to Port McArthur, including Groote Eylandt, Numbulwar, Ngukurr, and Port Roper remains in place.

Warnings for Cape Shield to Alyangula, Port McArthur to the Queensland border and inland areas including Bulman have been cancelled.

The BoM said there were gales around southern Groote Eylandt and these were starting to affect coastal areas between Nathan River and Bing Bong.

Gale conditions will extend along the coast to Port Roper and Numbular later on Wednesday morning, with gusts up to 120kmh expected.

The BoM said gales may extend to Alyangula depending on the movement of the system and wind gusts up to 100 kmh may extend inland to Ngukurr before the cyclone weakens.

There is are severe thunderstorm warnings for parts of western Arnhem District and a second line of storms in the Daly District, which are expected to move to the west or northwest.

Severe thunderstorms are likely to produce damaging winds and heavy rainfall that may lead to flash flooding with Nauiyu, Batchelor, Adelaide River, Pine Creek, Palumpa and Peppimenarti likely to be affected.

A storm warning for Carpentaria and Gregory districts has been cancelled.

EARLIER: Reformed tropical cyclone Tiffany is set to track south of Groote Eylandt on Wednesday morning and intensify to a category two system before making landfall on the mainland.

The Bureau of Meteorolgy has a warning zone in place from Cape Shield to the Queensland border, including Groote Eylandt, Numbulwar, Ngukurr, Bulman, Port Roper and Port McArthur.

Communities in the warning zone have been told to prepare for wet and windy conditions, with shelters opening on Groote Eylandt and the mainland.

The Northern Territory Emergency Services said residents in Alyangula and Numbulwar should shelter indoors as the weather conditions worsen.

The GEMCO Mess is open to staff and Alyangula residents and shelters are open at the Angurugu School Trade Training Centre, Umbakumba School Trade Training Centre, Milyakburra Cyclone Shelter and Numbulwar School.

About 50 people used the shelter in Numbulwar on Tuesday night. Most residents on Groote Eylandt were staying in their homes with low numbers at public shelters.

Severe thunderstorm warnings linked to the cyclone have been issued for the Darwin, Daly and Arnhem areas with flash flooding likely.

The Bureau of Meteorology said that a 78kmh wind gust was recorded at Tindal RAAF base near Katherine at 1.32am on Wednesday.

As of 3.30am Tiffany was a category one cyclone with sustained winds near the centre of 85 kmh and gusts of up to 120 kmh. It was about 95 km southeast of Groote Eylandt and 255 km east of Ngukurr moving west at 20 kmh.

The BoM said gales were continuing near Centre Island and developing near Port McArthur and on parts of Groote Eylandt. They would extend along the coast to Port Roper and Numbulwar this morning and extend to Cape Shield later in the day.

The cyclone was expected to cross the coast at about midday on Wednesday around Port Roper and Nathan River, with destructive wind gusts up to 130 kmh.

Gale-force winds with gusts up to 100 kmh could reach the area east of Beswick late on Wednesday with the storm system expected to weaken below cyclone strength later today once it hits land.

OTHER NEWS:

The BoM said that a storm tide between the Queensland border and Cape Shield, including Groote Eylandt, was expected as the cyclone tracked towards the mainland coast.

The higher-than-normal tides would bring damaging waves and dangerous flooding in the warning area on Wednesday and early Thursday.

As the cyclone moves inland heavy rain was predicted for parts of Arnhem, Carpentaria and Daly districts on Wednesday and Thursday, with flood and rising rivers likely.

A flood watch remains in place for North West and Carpentaria Coastal waters and preparations being made to manage any flood events.

Northern Territory Police, Fire and Emergency Services have reminded residents to stay away from floodwaters and not attempt to cross or drive through floodways and to be CrocWise.

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