Classified as a very severe cyclonic storm, Biparjoy was about 280km from Jakhau Port in Gujarat on Wednesday and was expected to make landfall on Thursday evening.
"It will touch Kutch-Saurashtra coast (in Gujarat) adjoining the Pakistan coast between Mandvi and Karachi and near Jakhau port on June 15 from 4pm to 8pm in India (1030-1430 GMT)," Manorama Mohanty, the Gujarat director of the India Meteorological Department (IMD), told reporters.
"As of now, our forecast is it will cross as a very severe cyclonic storm.
"After crossing, its intensity will fall and become a cyclonic storm and depression."
Meteorologists said the cyclone packed winds with maximum sustained speeds of 125 to 135km/h, gusting up to 150km/h, and warned high tides in the Arabian Sea could inundate low-lying areas along the coasts during landfall.
Temporary thatched houses could be completely destroyed while standing crops, plantations and roads were expected to face major damage, the IMD said in a statement, adding railways could also face disruption.
"Coastal districts of Gujarat have started receiving heavy rainfall," a senior official with the state-run IMD said.
"From Wednesday evening, the intensity of rainfall and wind speed would increase.
"On Thursday, extremely heavy rainfall is expected."
The official said some districts could get more than 200mm of rainfall on Thursday.
Eight districts in coastal Gujarat are expected to be affected, the state government said.
Fishing has been suspended until Friday, schools have declared holidays and many offshore oil installations and major ports have paused operations.
"We have evacuated more than 45,000 people so far," said Kamal Dayani, a senior Gujarat state government official.
School auditoriums and other government buildings have been converted into relief camps to provide shelter to displaced people in neighbouring Pakistan.
Ships and boats have been moved from some areas of Pakistan's coast and hospitals have been put on high alert.
Pakistan's National Disaster Management Authority said it expected about 100,000 people to have been evacuated by Wednesday morning.
