TAIPEI (Taiwan News) — Although the path of Tropical Storm Atsani is still uncertain, forecasters believe that the impact of the cyclone on Taiwan will be at its greatest by Friday (Nov. 6), possibly lingering over the weekend.
As of 2 a.m. this morning (Nov. 2), Atsani was located 1,160 kilometers southeast of Taiwan's southernmost tip of Eluanbi, moving northeast at a speed of 5 kilometers per hour, according to the Central Weather Bureau (CWB). The tropical storm has a radius of 80 kilometers and is packing maximum sustained winds of 64 kilometers per hour (kph) and gusts of up to 90 kph.
Map of Atsani's projected path (CWB image)
The CWB predicts that from Tuesday to Thursday (Nov. 3 to 5), northeasterly winds will affect the weather in northern and northeastern Taiwan, with the mercury beginning to drop. On Tuesday, brief rains are possible in the north, northeast, east, and southeast.
These sporadic rains are expected to continue on Wednesday and Thursday in Greater Taipei, eastern Taiwan, and the Hengchun Peninsula. Temperatures are expected to be coldest from Tuesday morning to Wednesday night, when lows will range between 19 and 21 degrees Celsius and may drop lower in open coastal areas and mountainous regions.
Wind probability map (CWB image)
Taiwanese weather expert Peng Chi-ming (彭啟明) said that Atsani currently lacks a guiding airflow, causing it to rotate in place. Peng said that by Wednesday or Thursday, Atsani will begin to intensify, possibly into a typhoon, and be driven by guiding airflow to the southern edge of a high-pressure ridge, likely causing it to move west toward the southern part of the Bashi Channel near the Philippines' Luzon Island.
Peng said that unlike the previous five tropical storms that struck the Philippines and South China Sea in October, this system will take a more northerly path. As it nears Taiwan over the course of the week, Peng predicts it will begin to affect rainfall in the eastern, northeastern, and southern parts of the country.
Map of Atsani's predicted path (JMA image)
Peng predicts Taiwan will feel the most intense impact of the storm starting on late Thursday or early Friday and through the weekend, possibly as late as Monday. He said that the various weather models currently diverge, with some predicting Atsani will move south to the waters off the coast of southern Taiwan, while others have it moving further north and impacting Taiwan directly.
Meteorologist Wu Der-rong (吳德榮) said that Atsani will reach a point of divergence on Tuesday. He said some models predict the storm will shift north to the seas off the coast of eastern Taiwan, while other models have the cyclone moving over Luzon and into the South China Sea.
Satellite map (CWB image)
Wu further explained that due to the divergence of simulated paths and a high degree of uncertainty, the distance between the storm and Taiwan will determine the extent to which the moisture from the Atsani's periphery affects the northern and eastern parts of the country by Friday.
The CWB's potential route forecast map predicts that Atsani will turn westward toward the Bashi Channel after making a loop in place. However, the outline of the storm's predicted path has expanded, with Luzon, the Bashi Channel, and southern Taiwan all within the realm of possibility.