Cyclone Aila, SITREP May 25, 2009
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Sphere India Unified Response Strategy SITUATION REPORT 25th May 2009 PART 1: SITUATION REPORT: At 21:00 PM UTC, Cyclonic Storm Aila over northwest & adjoining central Bay of Bengal moved north-northwestwards and lay centred over northwest Bay of Bengal near 20.0N 88.0E, or about 140 kms east of Paradip, 180 kms south of Sagar Island and 300 kms southwest of Khepupara, Bangladesh. Sphere India Secretariat, New Delhi (May 25, 2009) |Page 1 Satellite imagery indicates bending feature system. Warning: 03 at 1500 GMT Current Dvorak intensity of the system is T2.5. Position: 18.7N 88.4E Associated broken intense to very intense convection Location: 255 miles S of observed over the Bay of Bengal between 14.5N to Kolkata, India 22.0N and between 83.0E to 92.5E. The lowest cloud Movement : N at 3 knots top temperature due to convection is about -70 to -80C Maximum sustained winds: around the system center. 45 knots Maximum gusts: 55 knots Three minute sustained winds near the center is 40 Threatened landmasses: knots with gusts of 50 knots and a central pressure of 984 hPa. The state of the sea is HIGH to VERY HIGH India, Bangladesh around the system's center. Vertical wind shear of horizontal wind is between 10-15 knots around the center. The past 24 hours shear tendency is negative to the north of the system. The system lies close to the upper tropospheric ridge, which roughly runs along 20.0N in association with the anticyclonic circulation over Mynamar and adjoining north Bay of Bengal located to the east-northeast of the system. There is an upper tropospheric trough in westerlies west to the system. Sea surface temperature are warmer over north and central Bay of Bengal. Majority of NWP models also suggest intensification of the system and landfall over West Bengal and adjoining Bangladesh coast near 88.0E. Storm surge of a about 2-3 meters above astronomical tide is likely over coastal areas of West Bengal and adjoining Bangladesh coast at the time of landfall. Considering all the above, the system is likely to intensify further and move in a near northerly direction and cross West Bengal-Bangladesh coast near 88.0E near Sagar Island between 0900 and 1200 PM tomorrow. INDIA: The cyclonic storm “AILA” over northwest & adjoining central Bay of Bengal intensified further, moved northwards and lay centred at 0830 hours IST of today, the 25th May 2009 over northwest Bay of Bengal near lat. 20.50 N and long. 88.00 E, about 140 km east-southeast of Chandbali, 130 km south of Sagar Island and 280 km southwest of Khepupara (Bangladesh). The system is likely to intensify further and move in a near northerly direction and cross West Bengal coast near long. 88.00 E (near Sagar Island) today, the 25th May 2009 afternoon/evening. West Bengal: At 5.30pm, Cyclone Aila (name chosen from a list following a convention) was 500km south of Calcutta. “Even if Aila does not hit Calcutta, it would cause heavy rainfall,” said a senior Met official. Under Aila’s influence, rainfall is likely at most places over Gangetic Bengal, with heavy to very heavy rain at a few places. Isolated “extremely heavy rain” (over Sphere India Secretariat, New Delhi (May 25, 2009) |Page 2 250mm) is likely in Gangetic Bengal, including Calcutta and its adjacent areas, over the next 48 hours, said the official. On Sunday, the city received 4.6mm of rain till 5.30pm. The humidity ranged between 91 and 58 per cent. The discomfort index touched 60 degree Celsius, five degrees above normal. The temperature remained lower than usual — the maximum, 31.7 degree Celsius, was four degrees below normal. The minimum temperature was 26.2 degree Celsius, a degree below normal. The severe cyclonic storm 'SIDR' over east central and adjoining west central Bay of Bengal today moved further northwards and lay centred about 530 km south of Kolkata. According to an Indian Meteorological Department (IMD) report it was likely to intensify further and move in a northerly direction. Under its influence, rain or thundershowers are likely at most places in West Bengal and Orissa with heavy to very heavy falls at a few places. ''Isolated extremely heavy falls (25 cm or more) are likely over coastal districts of West Bengal and north Orissa during the next 48 hours causing floods in low lying areas,'' the IMD report said. Gale wind speed reaching up to 90 -120 kmph is likely to commence by noon today. As the system approaches the coast, the gale wind speed reaching up to 180-200 kmph are likely along and off the coastal areas. Orissa: Orissa raised the storm warning levels along its ports and alerted coastal residents as a cyclone formed in the Bay of Bengal. Fishermen have been asked not to go out to sea. “The danger signal number has been raised to seven and five at Chandbali and at Paradip ports,” D.C. Jena, an official of the meteorological centre here, told IANS. Cyclone Aila lay centred about 140 km east of Paradip, he said. The system is likely to intensify further and move in a northerly direction and cross the West Bengal coast later Monday, the official added. The state government Monday said all fishing operations in the sea have been suspended and fishermen have been alerted not to venture out to sea. “We have alerted all officials in the coastal districts to remain prepared to tackle any situation,” said, State Revenue Secretary, G.V.V. Sarma. BANGLADESH: The deep depressed that developed in the Bay of Bengal on Saturday, May 23, 2009, moved slightly northwards, intensifying into cyclonic storm Aila Sunday evening. It is likely to intensify further and move in a northerly direction. The Met Office said the depression was staying about 565km southwest off Sphere India Secretariat, New Delhi (May 25, 2009) |Page 3 Chittagong port, 510km southwest of Cox’s Bazar port and 460km south-southwest of Mongla port in the evening. Maritime ports of Chittagong, Cox’s Bazar and Mongla have been advised to hoist local warning Signal 4. All fishing boats and trawlers in the north Bay have been advised to remain in shelter till further notice. River ports imposed restriction on the plying of vessels of less than 65 feet in length in the evening. The maximum sustained wind speed within 54km of the storm centre is about 60kmph rising to 70kmph in gusts or squalls. The sea will remain rough. The system was likely to intensify and move in a northerly direction and cross the West Bengal-Bangladesh coast Monday evening, forecasts the India Meteorological Department. Reports reaching from coastal region said sea and river estuaries were very rough with waves rising up to 7 to 8 feet. People of char and coastal areas became panicked in the south, which was hit by cyclone Sidr on November 15, 2007. More than 200 trawlers with more than 3,000 fishermen on board could not get back to the shore because of high waves, according to the Mohipur-Alipur Fish Warehouse Association of Patuakhali and the Patharghata Fish Warehouse Association of Barguna, said the New Age correspondent in Patuakhali. It started raining heavily in the coastal region Saturday night. The Met Office at Kalapara recorded 85 millimetres of rainfall between 12:00pm Saturday and 6:00pm Sunday. The food and disaster management ministry has cancelled leaves of all the persons related to disaster management. The ministry has also asked all the volunteers to remain alert to the situation. The district and upazila administrations in southern districts also opened control rooms to monitor the development of the cyclone. The Red Crescent asked cyclone preparedness programme volunteers to get ready for emergencies, reports the correspondent in Barisal. The Patuakhali Deputy Commissioner, Md Riaz Ahmed, has asked all the upazila nirbahi officers to alert the people to the situation on PA system. A separate control room was opened in the district administration office and vehicles, Bangladesh Red Crescent Society volunteers and medical teams have been kept ready for emergencies. The Dhaka Met Office forecast that rain or thundershowers accompanied by temporary gusty to squally wind is likely over many places in Barisal, Khulna and Chittagong divisions and over one or two places in Rajshahi, Dhaka and Sylhet divisions with moderately heavy rainfalls in places in Khulna, Barisal and Chittagong divisions.Day temperature may fall by 1–2 degrees Celsius across the country (Bangladesh). Sphere India Secretariat, New Delhi (May 25, 2009) |Page 4 Wind & Rainfall Situation: West Bengal: The system, with maximum sustained wind speed of 200 kmph, was likely to cross the West Bengal-Bangladesh coast east of Sagar Island by around midnight tonight. The report said storm surge of height 6-7 metres above normal astronomical tide was likely over coastal areas of South 24 Parganas and Midnapore districts in West Bengal and Balasore, Bhadrak, Kendrapara and Jagatsinghpur districts in Orissa. Orissa: Under its influence, gale winds of speed reaching 70-80 kmph are likely to occur along and off the coast, he said. It may increase in the afternoon to 90 -100 kmph and may cause damage to thatched huts, uproot trees over coastal districts of north Orissa. Several parts of the coastal districts have been witnessing moderate to heavy rain during the past 24 hours. Based on latest analysis with Numerical Weather Prediction (NWP) models and other conventional techniques, estimated track and intensity of the system are given in the Table below: Date/Time(IST) Position Sustained maximum surface (lat. 0N/long.