Weather tracker: Japanese islands brace for Dujuan to become a typhoon again

Tropical Storm Dujuan is skirting the coast of Japan and despite avoiding a direct landfall, is still expected to leave its mark. Dujuan briefly reached typhoon status on Friday before weakening to a tropical storm again on Sunday morning. But it is expected to restrengthen back to a typhoon by Tuesday morning. Sustained winds could reach 80mph (129km/h), with gusts approaching 100mph.

Although mainland Japan has avoided a direct hit, Dujuan’s track takes it across the Izu Islands, where evacuation warnings are in place. Heavy rain, flooding and landslide alerts are widespread, with high waves adding another threat to exposed coastal areas and islands.

Some exceptional rainfall totals are expected, with about 200mm (7.9in) possible along the southern coasts of the Chubu and Kanto regions in just 24 hours – roughly equivalent to the average rainfall for the entire month of September. The Tokyo metropolitan area is among the areas facing the heaviest rain, with some models suggesting nearly 90mm could fall within six hours on Monday evening. Further south, the Izu peninsula could receive more than 80mm in just three hours – 38% of the month’s usual rainfall in a single evening. Dujuan is expected to continue north-eastwards before dissipating in the north-west Pacific later this week.

The Atlantic hurricane season remains unusually quiet, despite Tropical Storm Fay developing south-west of the Azores over the weekend. Fay is not expected to strengthen further, extending the record for the latest first hurricane to form in a hurricane season during the satellite era. The previous date record was 11 September, set in 2002 with Hurricane Gustav and equalled in 2013 with Hurricane Humberto.