New Tropical Depression South of Japan Expected to Become Typhoon No. 17

On Tuesday, August 11, 2026, the Japan Meteorological Agency (JMA) said a new tropical depression had formed south of Japan and was expected to intensify into a typhoon within 24 hours — which would make it Typhoon No. 17 for the 2026 season. Forecasters warned the system could turn northward later in the week and approach Honshu around August 15–16, just as Typhoon No. 15 (Chan-hom) was crossing eastern Japan.

Editor’s note: This article draws on JMA bulletins and reporting by Weathernews, Yahoo News Japan, and Nikkei Asia, August 11, 2026. Typhoon tracks and intensity forecasts can change; consult official JMA updates before making travel or safety decisions.

What JMA reported on August 11

JMA classified the system as tropical depression “a” (TDa) — a provisional label used before a storm earns an official typhoon number. As of 3:00 p.m. JST on August 11, the depression was centered south of Japan at roughly 21.0°N, 135.1°E, moving east at about 20 km/h.

Parameter	Value (Aug. 11, ~3 p.m. JST)
Central pressure	998 hPa
Max sustained winds	15 m/s (30 kt)
Max gusts	23 m/s (45 kt)
Development outlook	Typhoon within 24 hours

If it reaches tropical-storm strength, it will be named Typhoon No. 17 — the fourth named typhoon in August 2026, a month when Japan typically sees about 5.7 typhoon formations.

Forecast track: east first, then a sharp northward turn

Early guidance shows a two-phase path:

Phase 1 — Development and eastward drift (Aug. 11–13)

The depression is expected to continue eastward across warm Pacific waters, likely becoming a typhoon by Wednesday afternoon, August 12. JMA’s 24-hour outlook placed the future typhoon near the Ogasawara (Bonin) Islands waters, with sustained winds rising to about 18 m/s (35 kt) and central pressure near 994 hPa.

Phase 2 — Recurve toward Japan (Aug. 14–16)

After moving east, models show the system riding a large counterclockwise wind flow south of Japan — a pattern sometimes described in Japanese media as a sharp “left turn” or retrograde curve. By August 15–16, the storm could shift northwest and draw closer to Honshu, passing east of the main islands before potentially edging nearer to the Pacific coast.

Date (forecast)	Expected position / motion
Aug. 12	Near Ogasawara waters; typhoon status likely
Aug. 13	Northeast of Ogasawara; continuing north-northeast
Aug. 14	East of Japan; slowing
Aug. 15–16	Northwest drift; possible approach to Honshu

JMA stressed that intensity is not forecast to increase sharply — maximum winds may stay near 18 m/s through midweek. Uncertainty remains high on whether the storm will make landfall or stay offshore.

Context: back-to-back storms in a busy August

The announcement landed on the same day Typhoon Chan-hom (No. 15) was forecast to make landfall in the Kanto and Tohoku regions, bringing heavy rain and gale-force winds during the Bon holiday period. Chan-hom was expected to weaken to a tropical depression over the Sea of Japan by Wednesday, August 12.

Typhoon No. 17 would follow Typhoon No. 16 (Peyroh), keeping the western North Pacific in an active phase typical of late summer. Japanese forecasters note that approaches toward Japan increase from late August into autumn, making early track monitoring essential even for systems that initially move away from the archipelago.

Potential impacts if the track holds

Officials have not yet issued landfall warnings for Typhoon No. 17, but the projected path warrants attention for:

• Coastal waves and swell along Pacific-facing prefectures from Shikoku through Kanto and Tohoku
• Periods of rain and wind if the storm’s outer bands reach Honshu around August 15–16
• Travel disruption during the tail end of the Obon season, when many residents return from hometown visits
• Compound effects in areas still recovering from Chan-hom’s rainfall and wind

Residents in eastern and central Japan are advised to monitor JMA tropical cyclone bulletins, municipal disaster-alert apps, and local evacuation guidance. Preparedness steps include securing outdoor items, checking drainage, and knowing nearest evacuation sites — standard practice during Japan’s peak typhoon months.

How typhoon numbering works in Japan

JMA assigns sequential numbers to tropical storms and typhoons that reach naming thresholds in the western North Pacific. Tropical depressions below that threshold receive temporary letter labels (such as “a”) until they strengthen.

When Typhoon No. 17 is officially designated, it will receive an international name from the region’s naming list — separate from the Japanese number. Until then, media and forecast services refer to it as the “typhoon egg” (taifū no tamago) — a newly formed circulation expected to hatch into a full typhoon.

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Discussion

Japan is watching two storms in the same week — one crossing Honshu, another forming far to the south.

1. How do you prepare when a typhoon track is still uncertain days out?

Do you wait for a landfall warning, or start securing windows and stocking supplies as soon as a Honshu approach appears possible?

2. Does a second typhoon so soon after Chan-hom change how you think about late-summer travel in Japan?

Would you postpone a return from Obon, or trust that offshore tracks are common and disruption stays limited?

Share how you weigh forecast uncertainty against holiday plans and daily routines.

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This article is news and general safety information, not official emergency guidance. Follow instructions from local authorities and the Japan Meteorological Agency.