A rather large Tropical Storm Kompasu (Philippine name Maring) is passing just off the northern tip of Luzon, sweeping through the Babuyan islands this evening as a potent tropical storm with a large windfield that potentially extends across to southern Taiwan.
The storm is expected to strengthen when it enters the South China Sea, and is likely to become a Category 1 typhoon as it makes an approach on Hainan Island. Currently, the CDPS Rating is set to Stage 3 (Significant) for the Babuyan Group of islands this evening. Rainfall of over 100mm is likely in the area, with higher totals in northwestern Luzon in the mountain areas.
Hainan is expected to receive over 200mm of rainfall, and Vietnam may expect wide areas to receive 100mm late this week.
Kompasu will likely shrink and weaken after it strikes Hainan, but winds could still be a concern for the central and northern coasts of Vietnam.