According to the Japan Meteorological Agency (JMA), rain clouds developed over the two northeastern prefectures overnight into Friday owing to a low-pressure system approaching.
Weather officials said the accumulated amounts of rainfall since Monday through Friday in some of the northeastern regions have been as much as two times higher than the average amount for the month of August, reports Xinhua news agency.
Landslide alerts have been issued for the two prefectures, as well as Iwate prefecture, as a result of the deluge and the further downpours expected, the JMA said.
Up to 120 mm of rain is expected in Tohoku region, in the 24 hours through Saturday noon, while a further 50 to 100 mm of rain could fall in the 24-hour period through Sunday noon, the weather agency said.
In addition, the JMA also warned of possible landslides and flooding in low-lying areas as Meari moves northwards in the seas south of Japan.
Meari is on course to hit the Pacific side of eastern Japan on Saturday, the weather agency said.
The JMA said between 200 to 300 mm of rain could hit the Tokai region, while 100 to 150 mm is expected to drench the Kanto-Koshin region, over the next 24 hours.
Meari was upgraded to typhoon from a tropical storm on Friday morning, the weather agency said.