Why does the tropical depression ‘float’ over the sea, not going inland?

Why does the tropical depression hover over the sea, not going inland?  - Photo 1.

Tropical depression is still ‘floating’ over the waters of Da Nang – Quang Ngai – Photo: National Center for Hydrometeorological Forecasting

On the afternoon of September 12, Mr. Mai Van Khiem, director of the National Center for Hydro-meteorological Forecasting, said that last night, storm No. 5 (Hurricane Conson) entered the sea from Da Nang to Quang Ngai and weakened. weakened into a tropical depression.

At 6pm on September 12, a tropical depression was still on the sea from Da Nang to Quang Ngai. The strongest wind in the area near the center of the tropical depression is strong at level 7 (40-60km/h), level 9 shock.

It is forecasted that in the next 12 hours, the tropical depression will hardly move, then move slowly in the northwest direction, about 5km per hour and weaken into a low pressure area. The strongest wind in the center of the low pressure area dropped below level 6 (less than 40km/h).

According to Mr. Hoang Phuc Lam, deputy director of the National Center for Hydrometeorological Forecasting, in the afternoon of September 12, wind observations at Ly Son island recorded strong winds of level 7, gusts of level 9.

“Currently, the convection clouds near the center of the tropical depression are very weak, so the energy source for the tropical depression is limited, it will gradually weaken. In addition, the wind shear in the area of ​​the center of the tropical depression is very weak. is very large, so even if there is a source of energy, it will be scattered far away, not concentrated near the center of the tropical depression. Therefore, the tropical depression cannot strengthen into a storm,” said Mr. Lam. determined.

As for the reason why from last night to this afternoon, this tropical depression is still “hanging” from the coastal area of ​​Da Nang to Quang Ngai but has not yet reached the mainland, Mr. Khiem said that the tropical depression is in control. complex of three subtropical high-pressure systems, whose guiding currents govern the movement of storms.

Because the subtropical high pressure in the north weakens and moves to the east, while the subtropical high pressure in the east and west is stable, the tropical depression has almost little movement. It is forecasted that when Typhoon Chanthu moves to the north, the subtropical high pressure in the east encroaches to the west, then the tropical depression will move ashore.

“Currently, due to the topography, the forecast models are quite scattered for this tropical depression. However, we are inclined to forecast this afternoon or tonight, the tropical depression will go deep inland, clinging a bit. inland and then weakened into a low pressure area,” said Khiem.

Although the storm has weakened into a tropical depression, Mr. Khiem warned in the next 12 hours, from latitude 14.5 to 16.5 degrees north latitude; West of the longitude 110 degrees East longitude still has strong wind level 6, gust level 8. All activities in the hazard zone are subject to a high risk of being impacted by strong winds, high waves and tornadoes.

In the sea from Thua Thien Hue to Quang Ngai (including Ly Son and Cu Lao Cham island districts) there are strong winds of 6-7, level 9, waves of 2-4m high, rough seas.

Tonight, September 12, the coastal area from Da Nang to Quang Ngai has strong winds of level 5, level 6, level 8 shock. K.The area from Da Nang to the north of Quang Ngai has heavy rain, in some places it rains very heavily with a common rainfall of 50-100mm, in some places over 150mm.

From now to September 13, the area from Quang Tri to Thua Thien Hue has heavy to very heavy rain with a common rainfall of 100-200mm, sometimes over 200mm. From tonight to September 14, in the provinces from Quang Binh to Thanh Hoa, there will be moderate rain, heavy rain, very heavy rain in places with common rainfall of 50-150mm/time, in some places over 150mm/time.

According to the report of the National Steering Committee for Natural Disaster Prevention and Control, at 5:00 p.m. on September 12, storm No. 5 killed one person. 5 vehicles sunk (3 ships QNg 98436TS, QNg 92862TS and QNg 94443TS sunk at the mooring area, there were no people on board; ship QNg 95058TS and barge DNa0494 sank at sea and were rescued by Coast Guard ships), 2 ships were stranded. dried up in Thanh Khe, Da Nang.

59 houses with roofs removed, damaged (Thua Thien Hue 29 houses, Quang Ngai 25 houses; Kon Tum 2 houses; Gia Lai 3 houses) and 2,734ha of rice and crops were flooded or damaged (Quang Binh 290ha, Quang Tri 450ha, Quang Ngai: 1,604ha; Kon Tum 389ha).

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