On September 17, Lorna was seized by a frontal system, forcing it to move north-northeastwards and make landfall over the Boso Peninsula on the next day.

As the typhoon impacted Japan, it caused flooding that left minor damages in Tokyo Bay.

Lorna was first tracked by the Japan Meteorological Agency (JMA) as a 1,006 millibars (29.7 inHg) system at 06:00 UTC of September 10, northeast of Guam.

Only brief strengthening happened as now-Lorna inclined west-southwestwards and north-northwestwards by September 12 before intensifying into a modern-day Category 1 typhoon by 18:00 UTC of the next day as it dived southwestwards.

Lorna then peaked with winds of 100 knots (190 km/h; 120 mph) and a central estimated pressure of 950 millibars (28 inHg).

[1][2] Maintaining its intensity as it continued to move just west of the Philippines, it started to weaken at 06:00 UTC of September 16, being downgraded into a Category 2 typhoon; however its central pressure remained at its initial peak estimate.

Shortly after Lorna hit land, the weathermen of the United States noted that the typhoon is already becoming an extratropical low as it moved again over the Pacific Ocean.

[4] Starting on September 17, Japanese weathermen forecasted Lorna to slam the island of Honshu, after it briefly threatened Kyushu and Okinawa.

[4] Reports from Kyodo News indicated that all ships and vessels were already warned about the approaching storm by that day, being instructed by port managing individuals there to leave the harbors at Yokohama, while some were informed via radio about Lorna.

[5] Heavy rains first lashed the southern portions of Japan as Lorna turned northwestwards upon hitting land.

[5] Winds of 58 miles per hour (93 km/h) were registered over Yokohama as the eye of the typhoon passed there over the midnight of September 18.

[9] This number was finally materialized by the Japan Meteorological Agency in its disaster report about the storm, adding that 422 homes were damages and 43,762 of them were flooded.