A severe tropical cyclone is forecast to form off the western coast of Cape York on Friday, bringing gale force winds and possible heavy downpours.

The tropical low was on Thursday moving southwest towards the Gulf of Carpentaria, where it is expected to become a category three cyclone on Friday afternoon or Saturday, a Bureau of Meteorology forecaster said.

Winds gusting up to 90km/h are forecast to hit Cape York and the Gulf coast and there could be flood watches issued.

Forecasters will be keeping a close eye on the system throughout Friday and a warning will be issued if it intensifies, the BoM spokeswoman said.

AAP