A cyclonic storm centred over northwest Bay of Bengal moved southwestwards and lay close to Kalingapatnam in Andhra Pradesh early on Monday morning, the Cyclone Warning Centre said.
The CWC forecast widespread rainfall with heavy to very heavy fall at a few places over Orissa during the next 39 hours.
Besides, one-metre high storm surges were likely to be experienced over and above the normal astronomical tide in south Orissa coast at the time of landfall, the sources said, adding that the sea would be very rough.
Gale winds with speeds of 70 to 80 kmph could be experienced along and off South Orissa coast during the next 24 hours.
Danger signal number 5, hoisted at Gopalpur port, was replaced by signal number 7, while signal number 6 had been hoisted at Puri and Paradip.
Fishermen had been advised against venturing into the sea.
A CWC bulletin issued late on Sunday night said that the cyclonic storm was centred close to Gopalpur at 2330 hours, which was likely to cross the south Orissa-north Andhra coast.
But the system continued to drift in a southwesterly direction.
Heavy rains lashed Bhubaneswar last night but the downpour had stopped subsequently.