Unprecedented rainfall has poured down across the Top End, with one island off the coast of Darwin recording a potentially record-breaking 562mm in 24 hours.

Key points: The tropical low system bucketing rain on the Top End is tracking towards WA and is expected to develop into a tropical cyclone on Saturday

The tropical low system bucketing rain on the Top End is tracking towards WA and is expected to develop into a tropical cyclone on Saturday Communities in the Kimberley are bracing for heavy rainfall and winds of up to 100kph

Communities in the Kimberley are bracing for heavy rainfall and winds of up to 100kph The BOM said the rainfall had likely broken Northern Territory records

The deluge came as Darwin and Northern Territory communities remained on cyclone watch late into the week, before a tropical low system released heavy rain off the Darwin coast.

The Bureau of Meteorology (BOM) said the island of Dum In Mirrie, about 50 kilometres south-west of Darwin, received 562mm in the 24 hours from 9:00am on Friday morning.

BOM duty forecaster Billy Lynch said the Northern Territory's standing daily rainfall record was 544mm in the Roper Valley in 1963.

"I dusted off the archives to see if we've ever had rain that heavy before in 24 hours … it's looking like this is potentially a new Northern Territory record," he said.

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Mr Lynch said the rainfall on the island equated to about a third of its total since the last wet season.

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The tropical low, which was earlier predicted to develop into Tropical Cyclone Claudia, delivered heavy rainfall across the Top End

The Tiwi Island community of Pirlangimpi was hit with 164mm of rain in the same 24-hour period, Charles Point 185mm, while Darwin was showered with 67mm.

Cahills Crossing, the notorious crocodile hotspot, was reported to be 1.8m underwater on Friday morning. ( Supplied: Joel Spicer )

Kimberley braces for cyclone

Meanwhile, the tropical low system is tracking towards Western Australia and is expected to develop into a cyclone.

The storm is forecast to hit the northern tip of the Kimberley, where local Aboriginal communities are preparing for the arrival of intense weather conditions including winds up to 100kph.

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BOM duty forecaster Moses Raico said the Kimberley was "the biggest area of concern" as the weather system swept towards the Indian ocean.



"The [tropical] low is sitting offshore from the east coast of the Top End over the Timor Sea and is expected to continue its track further west away from the NT and closer towards WA," he said.

Build-up conditions forecast to return to Top End

As the tropical low moves west, the monsoon trough blanketing the Top End is expected to weaken over the next 24 hours, with temperatures in the mid-30s likely to return, Mr Lynch said.

"We're probably going to head back into more like build-up conditions into tomorrow and the start of next week, with those afternoon showers returning again," he said.

In Darwin, the BOM is predicting a top of 33 degrees Celsius on Sunday, 34C on Monday and 34C on Tuesday with chances of thunderstorms.