Typhoon Mikala Weakens, Shows Structural Separation Due to Vertical Wind Shear

Typhoon Mikala, this year's seventh tropical storm, has weakened from a strong typhoon to a moderate one, largely due to significant vertical wind shear. Former Meteorological Bureau Director Zheng Ming-dian highlighted this phenomenon, sharing satellite imagery on Facebook that showed a "high-low layer separation" within the typhoon. He explained that this occurs when the wind speeds at different atmospheric levels vary too greatly, causing convection to concentrate on the southwest side and leaving the low-level circulation center clearly visible.

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This is the impact of vertical wind shear!

According to Zheng, this "high-low layer separation" is a direct result of strong vertical wind shear. He further noted that while high clouds are moving over Taiwan, the central and northern parts of the island remain dry and hot. A southwesterly wind is present in the south, creating conditions favorable for afternoon convective development.

The Central Weather Administration issued a reminder that moisture levels are slightly higher than the previous day. Scattered brief showers are expected in eastern Taiwan (Hualien and Taitung), with localized brief thunderstorms possible in mountainous areas and southern regions in the afternoon. As of 2 a.m. today, Mikala's center was located 430 kilometers east-southeast of Eluanbi, moving north-north-east at 14 kilometers per hour.

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The difference in wind speed between the upper and lower atmosphere is too great, with strong convection concentrated on the southwest side, and the low-level circulation center is clearly visible. Sometimes this is called a 'high-low layer separation' phenomenon, which is the result of strong vertical wind shear.

The typhoon's path is primarily guided by the strength of the Pacific High pressure system, and its trajectory remains uncertain, with current projections indicating it is heading towards the seas near the Ryukyu Islands. Residents are advised to stay informed about weather updates.

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Today, high clouds are moving over Taiwan's sky, but the central and northern parts are still dry and hot. There is a southwesterly wind in the south, with conditions for afternoon convective development.