Tropical cyclone Fina has formed off the Top End as a category one storm system that is expected to intensify before making landfall in coming days.

A tropical low off Australia’s northern coast intensified overnight and was classified as a tropical cyclone early on Wednesday, Bureau of Meteorology senior meteorologist Miriam Bradbury said.

It is the first November cyclone declared in the area in 12 years.

Fina was moving very slowly east-north-east at about 12km/h on Wednesday, and was about 370 kilometres north-north-east of Darwin by midday (AEDT).

The weather bureau said Fina was expected to turn south towards the north-west Top End coast within 24 hours.

“Tropical Cyclone Fina is expected to move eastwards and intensify to category two by Wednesday night. Later on Thursday it should turn to the south then south-west, taking it towards the Northern Territory coast for a potential impact during Friday and Saturday,” it said.

The bureau warned of wind gusts of up to 120 km/h between Cape Don and Warruwi on Thursday morning, extending east to Maningrida later in the day and west to include the Tiwi Islands by late Friday.

Stronger wind gusts of up to 135km/h may develop between Cape Don and Warruwi late Thursday or early Friday morning as the system approaches the coast.

“Locally heavy falls are possible along coastal areas between the Tiwi Islands and Milingimbi from Friday,” BOM said.

“Tides may be higher than normal between Cape Don and Warruwi on high tides from early Thursday morning.”

Airport Development Group, which owns airports in Darwin, Alice Springs and Tennant Creek, said on Wednesday that Fina’s trajectory and intensity might force changes to flight schedules.

It warned all travellers and airport visitors to monitor BOM updates and local emergency services and check with their airline for schedule changes or cancellations.

The last time there was a November cyclone in the region was Alessia, a category one that hit in 2013. Before that, Severe Tropical Cyclone Joan ravaged parts of the northern and western coasts in 1975.

Forecaster Weatherzone warned Fina’s path could mean it passed near Darwin at the weekend, possibly while a category two.

“Tropical Cyclone Fina is a small system, which has helped it gain strength rapidly,” it said.

“Its small size also means that gale force winds only extend about 50 to 60 nautical miles from its core. Small tropical cyclones are able to fluctuate in strength more rapidly than larger systems, which means they can strengthen or weaken fairly quickly.”

The NT capital hasn’t had a cyclone since Marcus, also a category two, cut power to nearly 29,000 properties in March 2018.

In December 1974, Cyclone Tracy flattened Darwin and killed 66 people.

-with AAP