Satellite image of strong Typhoon Roke, taken around midday Tuesday Japan time (early Wednesday morning EDT). (NOAA)

By Bill Deger, Meteorologist

Sep 20, 2011; 3:44 AM ET

Powerful Typhoon Roke is on a collision course with Japan, with damagings winds and flooding rains on target to impact Tokyo and the Fukushima prefecture still reeling from last March’s tsunami.

A large portion of southern Japan, including more than 1.2 million people in Nagoya city, have been urged to evacuate ahead of the storm, which will impact areas that were devastated by mudslides and flooding from deadly Typhoon Talas earlier this month.

Spinning 535 miles southwest of Tokyo, Japan, Roke was packing maximum sustained winds of 110 mph as of late Tuesday afternoon Japan time (early Tuesday morning EDT), while producing waves of up to 26 feet high.

The strong typhoon is forecast to continue its trek to the northeast, maintaining its strength before making landfall along the south-central portion of Japan’s main island, Honshu, around Wednesday morning local time (Tuesday night EDT).

Such a track would bring the eye of the typhoon inland just west of Tokyo, eventually weakening but still packing a punch as it cuts across the middle of Japan and nearing the northeastern part of Honshu devastated by March’s Tohoku earthquake and tsunami.

Workers trying to control leakage into the basements of nuclear reactors at the Fukushima-Dai-Ichi power plant may need to be evacuated ahead of the storm, with more than 6 inches (150 mm) of rain expected to fall over the reeling prefecture.

Already more than 16 inches (400 mm) of rain has been dumped on the southern province of Miyazaki, west of the storm’s center. The outlook for similar rainfall totals have prompted concerns of flooding and mudslides near Nagoya, where a main river could flood.

“Highest rainfall owing to Roke will be at least 10 inches, enough to trigger flooding and landslides in the mostly hilly to mountainous landscape,” says International Weather Expert Jim Andrews.

Wind gusts at landfall could exceed 100 mph as the storm approaches the coasts of the Kansai and Chubu regions, with typhoon-force gusts possible in Tokyo by Wednesday afternoon.

“Winds will cause at least moderate damage along and near the direct path of Roke,” adds Andrews.

If Roke maintains its current track, Tokyo will fall in the northeastern quadrant of the storm, which typically contains the storm’s strongest winds and heaviest rains.

The rugged Japanese Alps will weaken the storm tremendously after landfall, though some re-intensification is possible when Roke reemerges over the sea northeast of Japan.