New Delhi, May 1 : The India Meteorological Department(IMD) said on Sunday that a cyclonic circulation is likely to form over South Andaman sea and neighbourhood around May 4 which may result in heavy rainfall at isolated places over Andaman & Nicobar Islands on May 5. "Under its influence, a Low-Pressure Area (LPA) is likely to form over the same region around May 6. It is likely to become more marked during subsequent 24 hours," an IMD bulletin said. Heavy rainfall at isolated places is very likely over Andaman & Nicobar Islands on May 5. Squally wind (speed reaching 40-50 kmph gusting to 60 kmph) is likely to prevail over southeast Bay of Bengal and adjoining South Andaman Sea on May 5 and 6. The IMD advisory asked the fishermen not to venture into these areas. Depending on the energy of the system based on wind speeds, the LPA develops into Depression, then into Deep Depression and then into a Cyclonic storm or even stronger system such as Super Cyclonic Storm. Normally, cyclones form over the north Indian Ocean in April and May, i.e. ahead of the monsoon. /IANS