TAIPEI (Taiwan News) — The consensus among weather bureaus is that Tropical Storm Nalgae (奈格) will first pass over the northern Philippine island of Luzon before heading north toward Taiwan.
Regardless of whether it takes a direct hit on Taiwan or not, it is considered likely to bring rain to northern and northeastern Taiwan starting early next week.
As of 2 a.m., Tropical Storm Nalgae was 1,530 kilometers southeast of Taiwan's southernmost point of Eluanbi moving west-northwest at a speed of 28 kilometers per hour (kph). It was packing maximum sustained winds of 82.8 kph and gusts of up to 108 kph, the Central Weather Bureau (CWB) reported.
Map of Tropical Storm Nalgae's projected path. (CWB image)
According to meteorologist Daniel Wu (吳德榮), Nalgae's westward movement will continue to intensify Friday (Oct. 28) and Saturday (Oct. 29). Wu said "when it turns and how big the angle is" will determine the impact on Taiwan.
In any case, there will be a lot of rain in northern and northeastern Taiwan next week and may be heavier than expected. He advised the public to beware of weather-inflicted hazards next week.
Starting on Saturday, Wu said there will be a lot more moisture in the air in areas windward from the storm, with rainfall more pronounced in Taoyuan and areas north and the eastern half of the country. Meanwhile, Hsinchu and parts of the south will see sunny to partly cloudy skies.
We predicted that due to the confluence of a northeast monsoon and the periphery of Nalgae, there is a chance of localized severe rainfall in northern Taiwan and the eastern half of the country from Sunday (Oct. 30) to Wednesday (Nov. 2).
Map of Tropical Storm Nalgae's projected path. (CWB image)
Wu said that as Nalgae develops over time, its projected path is constantly being adjusted and updated. He said that most computer simulations show that Nalgae will turn north and approach Taiwan after passing over Luzon Island. The probability that it continues to head westward after barreling over Luzon is relatively low.
The weather forecaster said that a more accurate projected path for Nalgae would not be available until after the weekend. However, Wu said that recent weather conditions prove that "typhoons do not need to be very close to Taiwan to bring a lot of rain."
Map of Tropical Storm Nalgae's projected path. (JMA screenshot)
He pointed out that Typhoon Nesat and last week's tropical depression saw more than 1,000 millimeters of rain to areas of Taiwan that were windward from the systems. Therefore, Wu said, regardless of whether Taiwan turns north or not, starting on Sunday, the dual influence of Tropical Storm Nalgae and a northeast monsoon may bring heavier-than-expected rain to mountainous areas of Taipei, Yilan, and other areas on the storm's periphery.
According to the forecaster, Nalgae will continue to move westward along the edge of a subtropical high pressure system over the coming two days. During the period when the tropical storm nears Luzon Island, Wu forecast that its intensity would continue to increase and it would become an intermediate-level typhoon.
Satellite image of Tropical Storm Nalgae. (NOAA GIF)
After passing over Luzon, Wu said that the terrain would weaken Nalgae. However, once it enters the South China Sea, Wu predicted that Nalgae will reintegrate and turn north toward Taiwan.
He forecast that low sea temperatures in the South China Sea could cause Nalgae to gradually weaken and even be downgraded back to a tropical depression. Wu predicted Nalgae will have its greatest intensity Friday and Saturday (Oct. 29).
Satellite image with water vapor view of Tropical Storm Nalgae. (NOAA image)
