Biparjoy, which means 'disaster' or 'calamity' in the Bengali language, was centred 100 km (62 miles) off Jakhau port in India's western state of Gujarat and 240 km (149 miles) off Pakistan's southern port of Karachi, weather officials said.
"We are expecting the cyclone to make landfall during the evening, around 8 or 8:30 p.m.," said Manorama Mohanty, the Gujarat director of the India Meteorological Department (IMD), which warned the process could last until midnight.
In its latest update, the IMD said that the cyclone's wall cloud had touched the Saurashtra coast in Gujarat.
It added that the cyclone could cause tidal waves in the Arabian Sea as high as 2 m to 3 m (7 to 10 ft) that could inundate low-lying coastal areas in both countries.
Classified as a category one storm, the least severe on a scale of one to five, Biparjoy appeared to have lost some of its intensity.
It was expected to have a maximum sustained wind speed of 115 to 125 kph (71 to 78 mph) gusting up to 140 kph (87 mph), down from Wednesday's estimate of 150 kph (93 mph).
More than 100,000 people have been evacuated from eight coastal districts in Gujarat likely to be affected by the cyclone and moved to shelters, the state government said.
Authorities said evacuations have been completed in Pakistan, where about 82,000 people were moved from high-risk coastal areas.
