A rare intense tropical cyclone has formed in the Arabian Sea and is forecast to dump eight years of rain in about 48 hours on typically arid regions of the Arabian Peninsula.

Cyclone Chapala has already generated sustained winds of 95 knots (175 km/h), according to the Joint Typhoon Warning Centre. It was also producing significant wave heights of more than seven metres.

Cyclone Chapala as it headed across the Arabian Sea. Credit:NOAA

Eric Holthaus, a US meteorologist, estimates the storm will dump as much as eight times the annual rainfall of coastal regions of Yemen and Oman. These regions typically collect just 100-130 millimetres of rain a year.

The port city of Salahah, in Oman, may face a coastal storm surge of as much as 4.5 metres, Mr Holthaus said, adding that it is likely to be heavy deluge and flooding that may pose the bigger threat.