As Cyclone Sitrang approaches the Bangladesh coast, the weather department has asked Mongla and Payra seaports to hoist danger signal No. 7. The coastal districts of Satkhira, Khulna, Bagerhat, Jhalakathi, Pirojpur, Barguna, Patuakhali, Bhola, Barishal, Lakshmipur, Chandpur, Noakhali, Feni and their offshore islands also came under danger signal No. 7. Chattogram and Cox's Bazar ports have been advised to hoist danger signal No. 6. Read Cyclone Sitrang: Fire service on high alert, opens monitoring cell According to the Bangladesh Meteorological Department, 11 cyclone warning signals are used for seaports.  Here’s what the warning signals mean Distant cautionary signal No. 1 There is a region of squally weather – wind speed of 61 kilometres per hour – in the distant sea where a storm may form. Distant warning signal No. 2 A storm – wind speed of 62-88 kilometres per hour – has formed in the distant deep sea; ships may fall into danger if they leave the harbour. Read Cyclone Sitrang: Power entities open control rooms Local cautionary signal No. 3 The port is threatened by squally weather – wind speed of 40-50 kilometres per hour. Local warning signal No. 4 The port is threatened by a storm – wind speed of 51-61 kilometres per hour – but it does not appear that the danger is serious enough to justify extreme precautionary measures. Danger signal No. 5 The port will experience severe weather from a storm of slight or moderate intensity – wind speed of 62-88 kilometres per hour – that is expected to cross the coast to the south of Chattogram port or Cox's Bazar port and east of Mongla port. Read Cyclone Sitrang: Many areas in Dhaka, Narayanganj plunge into darkness following disruption in power supply Danger signal No. 6 The port will experience severe weather from a storm of slight or moderate intensity – wind speed of 62-88 kilometres per hour – that is expected to cross the coast to the north of Chattogram port or Cox's Bazar port and west of Mongla port. Danger signal No. 7 The port will experience severe weather from a storm of light or moderate intensity – wind speed of 62-88 kilometres per hour – that is expected to cross over or near the port. Great danger signal No. 8 The port will experience severe weather from a storm of great intensity – wind speed of 89 kilometres per hour or more – that is expected to cross the coast to the south of Chattogram port or Cox's Bazar port and to the east of Mongla port. Read Cyclone Sitrang: Educational institutions in 3 divisions declared closed Great danger signal No. 9 The port will experience severe weather from a storm of great intensity – wind speed of 89 kilometres per hour or more – that is expected to cross the coast to the north or Chattagram port or Cox's Bazar and to the west of Mongla port. Great danger signal No. 10 The port will experience severe weather from a storm of great intensity – wind speed of 89 kilometres per hour or more – that is expected to cross over or near the port. Failure of communication No. 11 Communications with the Storm Warning Centre have broken down and local officers consider that a devastating cyclone is following. Read 110 evacuated from isolated char in Bhola ahead of Sitrang landfall

The maritime ports of Chattogram, Cox’s Bazar, Mongla and Payra in Bangladesh have been advised to hoist at the mast local cautionary signage to alert vessels of a possible squall. The weather office's advisory for cautionary signal number three -- which means that a depression has formed and may affect the port later -- comes in the wake of the well-marked low over the southwestern part of Bangladesh and adjoining areas lying over the western part of Bangladesh and the adjoining Indian state of West Bengal. Read:Maritime ports asked to hoist cautionary signal 3 “Under its influence, deep convection is taking place and a steep pressure gradient lies over the North Bay and adjoining areas,” said a Met office bulletin. Squally weather may affect the maritime ports, the North Bay and the adjoining coastal areas of Bangladesh, it added. "All boats and trawlers in the North Bay have been advised to remain close to the coast and proceed with caution until further notice." According to the daily weather bulletin, light to moderate rainfall or thunder showers accompanied by temporary gusty or squally wind may occur at most places over Rangpur, Rajshahi, Dhaka, Khulna, Barishal and Chattogram divisions. Read:Cautionary signal 3 for Bangladesh maritime ports Similarly, many places over Mymensingh and Sylhet divisions may experience moderately heavy to very heavy rainfall, as per the bulletin. Day and night temperatures may remain nearly unchanged over the country.