Severe Tropical Storm Dujuan — large, and starting to arrive

CRESTING · September 18, 2026 · NO. 0918

THE STORM

Yesterday this storm had a name and a target. This morning it has a size. The Philippine service's 4:00 AM bulletin carries Dujuan as a Severe Tropical Storm at 110 km/h, about 2,460 km east of the Philippines and outside its area of responsibility — no Philippine threat, at that distance. Tokyo desks relay Japan's agency taking it from 996 hPa with gusts of 30 m/s early Thursday to a projected 980 hPa with gusts near 40 m/s by Friday night near Ogasawara, and — the part that changed — describing it as a large system, with gale-force winds reaching about 950 km on its northern side. By intensity it is an ordinary storm and this page will keep saying so. By reach it is not, and reach is what decides who gets wet.

What it is aimed at has not changed and did not need to. Tokyo desks report Kantō-Kōshin at about 365 percent of its normal rainfall since September 1 — a newspaper figure rather than an agency product, and marked reported here for that reason. Two and a half weeks of rain leaves a hillside that has stopped absorbing and a drainage system with no headroom. Onto that, the wind and rain strengthen from today, worst Sep 18–19: Ogasawara on Saturday, the Izu Islands on Sunday, and by Monday the centre about 100 km off the Boso Peninsula and 180 km from central Tokyo — across Silver Week, the stretch when the country is travelling. A wide gale field means the effects arrive long before the centre, and far beyond it. That is the danger and it is also, exactly, the warning.

It is worth saying plainly what this morning can and cannot tell anyone. A 950 km gale field is a hard number about a soft weekend: it means an Izu harbourmaster, a Shinkansen dispatcher and a family with holiday tickets can all see the days compromised before a single cloud crosses the coast, and it means the honest forecast pairs that reach with the memory already in the soil. What a cross-agency board cannot carry is the second half — that board rates Dujuan green on about 9,875 people exposed to Category-1 winds at scan time, which is true, and is counting the wrong thing for this storm. Nobody can say this morning what the weekend costs any particular household in Izu or Kantō, and this page will not pretend to: nothing has happened yet, so there is no toll to print, and none is invented. What is on the record is a track, a size, a holiday, and two and a half weeks of accumulated rain — and three of those four were knowable before the rain began. (Handled with care.)

THE RECORD

3 turning points on record since Sep 15.

Sep 17↑ firmed

Sep 16emerging → building · intensified sharply

Sep 15appeared, emerging

THE FACTS

THE BULLETIN, AT 4 AMSevere Tropical Storm Dujuan, maximum sustained winds 110 km/h, about 2,460 km east of the Philippines and outside the Philippine Area of Responsibility — no Philippine threat. The unit is the issuing service's own and is not converted onto anyone else's scale here.

WHAT GREW WAS THE REACHJapan's agency, relayed by Tokyo desks: 996 hPa with gusts of 30 m/s early Thursday, projected to 980 hPa with gusts near 40 m/s by Friday night near Ogasawara — and the system now described as large, with gale-force winds about 950 km on its northern side. The agency's own pages were JavaScript-rendered this run, so these figures are desk relays.

THE GROUND, NOT THE WINDAbout 365 percent of normal rainfall since Sep 1 across Kantō-Kōshin. Wind and rain strengthen from today, worst Sep 18–19, reaching Ogasawara Saturday and the Izu Islands Sunday with the centre near Boso on Monday, across Silver Week. A cross-agency board rates the storm green on about 9,875 exposed to Category-1 wind — a wind footprint, not rain on loaded soil.

AND ELSEWHERE — THE ATLANTIC'S ONE CANDIDATE FOLDED, AND THE AMERICAN RAIN RELOADED NORTHInvest AL98 went from about 40 and 40 to 10 and 10 east of Bermuda, development becoming increasingly unlikely, leaving a record-late season with no 2026 hurricane and no obvious successor — while the East Pacific lit three areas, two of them probable depressions. In the United States the Southwest Moderate risk eased to two New Mexico warnings and the rain reloaded north — Rockies and Plains into the Upper Mississippi Valley and Midwest, plus a separate Florida threat — with record-challenging heat building South-Central as advisories fell 15 to 10.

AND ELSEWHERE — TWO LEDGERS MOVED APART, AND THE SOUTHERN BOARD RAN STRONGNepal's ledger rose to a reported 1,399 recovered and about 6,150 missing while Pakistan's held frozen at 183 dead and 515 injured on a Sep-11/12 vintage — both printed at the vintage they have. South Africa runs Orange level 6 on the KwaZulu-Natal coast and level 5 in the Eastern Cape on the cut-off low's last day; southern Vietnam's five-day spell began today; Nigeria's regulated release reached its scheduled second day; and Italy stepped orange down to yellow across 12 regions. (Handled with care.)

WHO IT TOUCHES

Public safetynine national warning systems live at once, one with danger-to-life wording, one with a published clock, and the biggest one still entirely ahead

Aviationa holiday-weekend flight bank into Tokyo that can still be re-cut, and a Midwest and Florida rain day that cannot

Supply chainsa holiday rail and port weekend in Japan, a dated release on an African waterway, a flooding logistics region in Vietnam, and a river that is still too low to load

Maritimean island chain inside a large storm's gale field, three genesis areas offshore, and a coast under Orange 6 seas

Events and venuesa national holiday weekend inside a large storm's rain shield, and outdoor crowds under record-challenging heat at the other end of the board

Agricultureharvest and livestock decisions on five continents, a monsoon that means opposite things at each end of one country, and one release a grower can read off a timetable

Energycooling load rising in one hemisphere while heating load holds in the other, and a hydropower release running to a published plan

CONNECTED

The forecast took one headline back and made another one bigger on the same morning — an Atlantic invest went 30 to 40 to 10 with development becoming increasingly unlikely, while a West Pacific storm that was called a marginal typhoon turned out to be a large one with gale winds about 950 km out.

In both of these the storm is the smaller half of the problem — Dujuan's ordinary rain is dangerous because Kanto-Koshin is reported at about 365 percent of normal since Sep 1, and southern Vietnam's five-day spell opens on a country whose northern half is still draining submerged homes.