Sourced numbers convert at build, to the same rounding the
issuing agency publishes. Translation is machine-assisted; every measurement is
carried across unchanged.
The Atmosphere Today
No. 0919 · Saturday, September 19, 2026 · Morning run
A typhoon's rain reaches eastern Japan, onto ground already soaked for a fortnight.
Two of the loudest flood claims on this board were withdrawn overnight by the services that issued them.
AT THIS HOURTyphoon strength, and the Ogasawara rain is falling now975 hPa, maximum sustained winds about 108 km/h on a 10-minute average with gusts near 162 km/h, about 170 km south-south-east of Chichijima, moving west-north-west at roughly 35 km/h. A second national service classifies it a typhoon at 120 km/h and places it 2,000 km east-north-east of northern Luzon, outside its area of responsibility — so there is no Philippine threat from this storm. Reported through desk relay, because the issuing service's own bulletin pages were JavaScript-rendered this run.
WHAT THE GROUND IS ALREADY HOLDINGAbout two weeks of record rain across eastern Japan, before a drop of this storm landsThe reason this is the lead rather than a strip line. Eastern Japan's soil has taken about two weeks of record rain, and saturated ground converts new rainfall into runoff and slope failure instead of storage. No soil-moisture figure is printed here because none was directly read this run — the saturation is carried as reported, and it is the mechanism, not a number, that is being asserted. A cross-agency board rates the storm green on about 10,193 people exposed to Category-1-equivalent winds, which measures the wind field and not the water.
WHEN IT REACHES THE MAINLANDIzu Islands Sunday, Kanto and Tokyo Monday — across the Silver Week holidayOgasawara takes up to 250 mm in 24 hours through midday today; the Izu Islands on Sunday; Kanto, including Tokyo, on Monday, with the system going extratropical early next week. That is one day of notice for the islands and three for the mainland, falling across a holiday weekend when rail, air and ferry loads are at their heaviest. A small change in the turn point shifts how close the core passes the Izu chain and the Kanto coast, so the timing carries medium confidence and the mechanism carries high.
Dujuan crossed the typhoon line overnight, and the more useful fact is that nobody in eastern Japan should be reading the label. The storm sits at 975 hPa with maximum sustained winds near 108 km/h on the issuing service's ten-minute average — gusting to about 162 km/h — roughly 170 km south-south-east of Chichijima and moving west-north-west at about 35 km/h. A second national service, tracking it from the south, classifies it a typhoon at 120 km/h and notes it is 2,000 km east-north-east of northern Luzon and outside its own area of responsibility. Those two numbers are not in conflict; they are measured over different averaging periods, and neither is converted onto the other here. What both describe is an ordinary-strength storm on a track that is about to intersect an extraordinary antecedent.
That antecedent is the story. Eastern Japan has absorbed roughly two weeks of record rain, which means the ground under the Kanto plain and the hills behind it is doing the hydrological equivalent of standing in a full bath. Rain onto saturated soil does not infiltrate; it runs, and it runs faster and arrives higher than the same rain on dry ground, and on a slope it takes the slope with it. The track hands out the timing in stages: the Ogasawara Islands take up to 250 mm in 24 hours through midday today, the Izu Islands get it Sunday, and the Kanto region including Tokyo gets it Monday, before the system goes extratropical early next week. The wind will break some things. The water is what moves hillsides.
The timing is the part worth acting on rather than watching. This lands across Silver Week, when the rail network is carrying holiday volume rather than commuter volume, the ferries to the Izu Islands are full, and the people on the coast are disproportionately visitors who do not know which road floods. A forecast that gives an island chain a day of notice, a mainland region three, and names the mechanism as water on loaded ground rather than a category is a forecast somebody can still act on — pre-cancel a flight bank, hold a ferry, stage pumps at the slope that failed last time, move a holiday plan by a day. The storm will do what it does. The lead time is the only variable still in human hands, and this morning there is still some of it left.
HELD STEADYTyphoon Dujuan — the line crossed · The American rain rides east — Great Lakes today · Vietnam floods at both ends — the north still under water · The Philippines run on the south-west monsoon · Nepal — the reported ledger moved up overnight as the search went on · The American fire ledger — level 3 held · New Zealand — a trough crosses the centre · Bangladesh — carried · The Chinese south-west and north-west — carried · The Caribbean Sea and the Gulf of Mexico · The central North Pacific · The North Indian Ocean · Australia · South-west Indian
claim withdrawn — Two loud claims lost their basis on the same morning, at opposite ends of one continent — and the retraction is the finding. In Nigeria the story that a dam release was flooding the Benue is debunked by the agency that would know: the reservoir is impounding at 209.82 m of a 216 m maximum, and the flooding is rain-driven. In South Africa the cut-off low framed as a coastal danger-to-life event stepped the KwaZulu-Natal coast down from Orange level 6 to Yellow level 2. Neither correction is a relief and neither is an error being hidden.
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Primary pages were gated this run, and the aggregator relay returned year-mixing content naming older storms that could not be verified against a primary service — so it…
QUIET — THE CARIBBEAN SEA AND THE GULF OF MEXICO · THE CENTRAL NORTH PACIFIC · THE NORTH INDIAN OCEAN · AUSTRALIA · SOUTH-WEST INDIAN, AUSTRALIAN REGION AND SOUTH PACIFIC
three warning systems arriving on three different clocks, and two more that just told the public to un-believe something
The job today is lead time, and it is a different amount in every place on this list. In Japan there are three days before the rain reaches Kanto and hours before it reaches Ogasawara — which is time to stage pumps on the slopes that failed under the last two weeks of rain, not time to watch a track map. In the American Great Lakes and Ohio Valley the lead time is today, and it collapses to the oldest decision in the business: close the low-water crossing before a driver finds it. In northern Vietnam the lead time is gone — more than 2,000 homes are already submerged and more than 1,000 households isolated, so the work is access and resupply, not warning. And in Nigeria the change is what people should stop watching: with the dam impounding at 209.82 m of 216, the trigger is rainfall on a loaded basin, and a community told to watch a release date is a community watching the wrong thing. South Africa shows the mirror image — the coastal orange came down while an Orange level 5 went up inland, and the duty roster has to move with it. The person at the end of every one of these chains is deciding whether to move tonight or wait an hour.
a typhoon reaching the Tokyo area on a holiday Monday, a hail day over the central Plains, and a rain axis crossing the north-eastern hubs
Three separate reasons to buffer a bank, and only one of them is the storm everybody is watching. The Kanto arrival on Monday lands on a Silver Week return day, so the decision is whether to thin the Haneda and Narita banks Sunday evening rather than cancel into a full airport Monday morning — the storm is ordinary, the passenger load is not. Over the central Plains the upgraded Slight risk with large hail as the primary mode is a ramp and airframe problem before it is a delay problem: hail is the hazard that damages aircraft on the ground. Across the Midwest into the North-east the weekend rain axis moves onto the busiest hub geography in the country Sunday, which is a flow-management call made the night before. And the 108 °F heat index across the South-Central is a ground-crew limit and a density-altitude note on short runways. Who owns the call: a network operations centre choosing which banks to protect, a day ahead.
the Kanto corridor under a Monday arrival, the Great-Lakes freight lanes under the weekend rain, and two Vietnamese logistics regions flooded at once
The exposure is concentrated where a single day of disruption is expensive.Kanto on Monday is the densest rail-and-road freight geography in Japan taking a typhoon's rain, on a holiday when the network is already running a different timetable — the cheap move is to reschedule Monday's inland legs now and let the holiday absorb it. In the American Midwest and Great Lakes, heavy rain rides east into the Mid-Atlantic and North-east on Sunday across the corridors that feed the eastern distribution centres; it is a delay-and-detour day rather than a damage day, provided the crossings are managed. Vietnam is the harder one: the north is still flooded with more than 1,000 households isolated and roads out, while the south takes 10 to 20 cm on Ho Chi Minh City through about Sep 24 — two ends of one logistics network degraded simultaneously, which is not how contingency plans are usually written. And on the Rio Grande do Sul coast, winds to 100 km/h with hail is a port-and-yard call for Sep 19 into Sep 20. Who owns it: a planner choosing between a detour cost today and a stranded load tomorrow.
a typhoon crossing island ferry routes, an extratropical cyclone on a South American coast, and a marine alert count that is carrying most of an American board
The water is where today's alert volume actually sits. The American national board reads 362 active alerts of which 294 are marine against just 68 on land — an aggregate that looks like a busy country and is mostly a busy coastline, and the kind of total that misleads anyone reading the headline number instead of the split. Around Japan, the Ogasawara and Izu ferry routes are the first things the storm touches and the last to be restored; holding a sailing on Saturday is cheaper than recovering a stranded holiday manifest on Monday. On the Rio Grande do Sul coast an extratropical cyclone forms Sep 19 into Sep 20 with winds to 100 km/h — a berth, anchorage and small-craft decision on a short fuse. In the Saudi south-west highlands, red flash-flood alerts sit above the coastal plain, where torrents reach the shore road faster than they reach the forecast. Who owns the call: a harbourmaster with a sailing list and a falling barometer.
a national holiday weekend under a typhoon's rain, and an American Saturday with hail in the Plains and a record-challenging heat index in the South
Two crowd problems, one made of water and one made of heat.Silver Week puts Japanese crowds on coasts, islands and mountain roads exactly as the rain arrives — Izu on Sunday, Kanto on Monday — and the call that has to be made today is whether an outdoor event goes ahead on ground that has been saturated for a fortnight, because the failure mode is a slope or a car park, not a cancelled stage. Across the American South-Central, a heat index near 108 °F is a medical-planning number for any Saturday gathering: shade, water, and a triage plan sized for the index rather than the air temperature. Over the central Plains, the upgraded Slight risk with large hail is the one that empties a field fast — hail arrives with minutes of notice and no safe outdoor posture. Who owns the call: an event safety officer who has to decide before the gates open, not after.
a 108 °F heat index across nine states, flood-water exposure on three continents, and two humanitarian ledgers still being counted
Heat is the acute call and water is the slow one.Thirteen heat advisories from Arkansas to Alabama, plus Kansas, Puerto Rico and the US Virgin Islands, at an index near 108 °F, is a cooling-centre and outdoor-worker decision for today — the advisory tier, not the warning tier, is the one that covers most of the people actually exposed. Behind it, standing flood water in northern Vietnam and along the Benue is a waterborne-disease and safe-water problem that peaks days after the rain stops and gets less attention for exactly that reason; the Nigerian correction changes the planning window, because rain-driven flooding has no published schedule the way a release would. And in Nepal, a recovery still running against a reported at least 1,410 dead and about 6,145 missing is a mental-health and identification burden as much as a medical one, including for the 607 foreign nationals from 34 countries among the counted. (Handled with care.) Who owns it: a public-health officer sequencing today's heat against next week's water.
a monsoon retreating over one Indian state while it soaks six others, hail over the central Plains, and a 108 °F field-work ceiling
The same bulletin is a harvest signal in one district and a brace signal in the next. In India, withdrawal conditions are becoming favourable over parts of West Rajasthan against a 15 percent seasonal deficit — the end-of-season read a farm manager plans the next crop against — while heavy 64.5 to 115.5 mm and very heavy 115.6 to 204.4 mm rain crosses west Madhya Pradesh, west Uttar Pradesh, Haryana, Delhi, east Rajasthan, Uttarakhand and Himachal over three days, with 11 to 20 cm already down in Gujarat and Saurashtra. Cut early and accept the loss, or hold and risk the field. Across the central Plains, large hail on an upgraded Slight risk is the fastest total-loss mechanism standing crops face, and it is a today decision about equipment and cover, not a seasonal one. In the American South, a 108 °F index is a labour ceiling: field work moves to dawn or it does not happen safely. And on the Patagonian plateau, 15 to 60 cm of snow with minima near minus 10 °C is a livestock-movement call before Spring Day. Who owns it: a farm manager with a three-day forecast and a fixed crew.
an evening load peak under a 108 °F index, wind and hail on two continents, and a river that is still a level rather than an event
Load on one side of the ledger, physical asset risk on the other. A heat index near 108 °F across thirteen advisory areas is an evening-peak problem for the South-Central grid on a Saturday, when the demand curve and the crew roster are both thinner than a weekday. Large hail over the central Plains is the hazard that damages solar arrays and substation equipment rather than merely tripping a line, and it is worth a pre-position rather than a post-event callout. On the Rio Grande do Sul coast, winds to 100 km/h with hail on Sep 19 into Sep 20 is a distribution-network and restoration-staging call for southern Brazil. And on the Rhine at Kaub, 25.0 cm — up 1 cm, status still low — keeps barge loading a planning constraint rather than a disruption: the number to watch is the direction, and this run it finally moved up. Who owns it: a control-room operator deciding tonight's reserve and tomorrow's crew.
