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Storm · Forecast to formSea of Japan low · L-2026-0069

A new low could form southwest of Vladivostok on Sunday night

Could pass near Seoul Sun afternoon; 2 in 10 forecasts bring it within 160 km.

Updated Sun., Sept. 27, 6:58 a.m. GMT+9 · 103 from NOAA, ECMWF and Environment CanadaMedium confidence

Could pass near Seoul Sun afternoon; 2 in 10 forecasts bring it within 160 km.

Quick answers

As of the Sat 26 Sep 12Z model run · updated Sun., Sept. 27, 6:58 a.m. GMT+9

Where will the Sea of Japan low form?
Forecasts that develop it have the centre forming about 350 kilometres southwest of Vladivostok on Sunday night. The most likely path takes it about 450 kilometres southwest of Petropavlovsk-Kamchatsky by Wednesday night.
When will the Sea of Japan low be closest to Seoul?
Most likely Sunday, Sept. 27, around 3 p.m. GMT+9. Across the forecasts the comes between Sun 2 p.m. and Sun 9 p.m. GMT+9. Most forecasts pass the centre 50–1,750 kilometres east of Seoul.
What is the chance it passes within 160 kilometres of Seoul?
17%: 2 in 10 forecasts bring the storm’s centre within 160 kilometres of Seoul. Elsewhere: Vladivostok 18%, Busan 12%. Rain, wind and coastal flooding can reach well beyond 160 kilometres from the centre.
How sure is the forecast?
Medium confidence. 44 of 103 show the storm, and they broadly on its early path (agreement 72 out of 100).
Do the AI and physics models agree?
Broadly, with some differences. Chance within 160 kilometres of Seoul: AI ensembles (AIFS ENS) 6%, physics ensembles (GEFS, GEPS) 27%. By model: GEFS 26%, AIFS ENS 6%, GEPS 29%. By Tuesday night the AI ensembles’ middle track is about 250 kilometres north of the physics ensembles’. At its deepest, the AI ensembles take it to about 989 and the physics ensembles to about 986 hPa.
Will the Sea of Japan low become a bomb cyclone?
Unlikely. None of the 103 deepen it fast enough to count as a (a pressure fall of roughly 24 in 24 hours, adjusted for latitude).

What we know

Where it forms. The forecasts that show it have the centre taking shape about 350 kilometres southwest of Vladivostok on Sunday night, at about 1,006 .

How sure. 44 of 103 show the storm, and they broadly on its early path.1

How strong. It is still strengthening: forecasts deepen it to about 988 by Tuesday night. None of them turn it into a rapidly deepening .

What’s uncertain

Whether it forms. 44 of 103 develop it; the rest do not. Storms that exist only in the forecast can change a lot from run to run.

How close it comes. For Seoul, most forecasts put the between 50 and 1,750 kilometres away, most likely Sunday 3 p.m.

Later on. The forecasts fan out after Monday. By Thursday afternoon, the is about 2,050 kilometres across.2

When it arrives

When the centre passes closest to each place, earliest to latest across the forecasts. Places are ordered by the most likely time.

Window of Most likely timeNight
is the share of forecasts that bring the centre within 160 kilometres. Shaded columns are night; times are in your time zone.
DetailsStrength, sources and the fine print

How strong it gets

Central pressure over time. The line is the middle forecast; the band holds 8 in 10 of them.

(lower is stronger)

Times are shown in

Where the forecasts come from

ModelTracks
NOAA
21 of 3112Z
ECMWF
8 of 5112Z
Environment Canada
15 of 2112Z

Also tracking

  1. Bering Sea lowLikely to pass 20–320 km from Kodiak Sun evening; 7 in 10 forecasts bring it within 160 kmL-2026-0002
  2. September Nor’easterLikely to pass 20–140 km S of New York Sun afternoon; nearly all forecasts bring it within 160 kmNE-2026-01
  3. Ross Sea lowVery deep low bottoming out near 943 hPa Sat afternoon, in the Southern Hemisphere; all 103 forecasts show itL-2026-0057
  4. Bellingshausen Sea lowVery deep low in the Southern Hemisphere, near 958 hPa now and filling; nearly all forecasts show itL-2026-0064
  5. East Pacific tropical system off MexicoTropical system over the North Pacific, near 978 hPa now and filling; nearly all forecasts show itL-2026-0061
  6. See all 55 storms →

Notes

  1. Forecast tracks from the 12Z model run: GEFS (31), AIFS ENS (51), GEPS (21). A single run is one high-resolution forecast; ensemble forecasts are the same model run many times with small changes.
  2. The cone encloses where the centre is expected to be about two times in three at each hour, from the spread of the forecasts, widened by 20 percent; not yet calibrated against past storms. It shows uncertainty in the track, not the size of the storm.
  3. Shading shows the share of forecasts that bring the centre within 160 kilometres of a spot at any time in the next 7 days. Rain, wind and surge can reach much farther.
  4. Times are in your time zone. Arrival windows run from the earliest to the latest closest approach across forecasts that bring the centre within about 300 miles (500 km).
  5. NOAA/NCEP.
  6. Data Source: Environment and Climate Change Canada.
  7. This service is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF). Source: www.ecmwf.int. Licence: CC BY 4.0.
  8. Cyclone tracks computed by WeatherNick from the model fields.
  9. Not an official forecast. For warnings and decisions, follow your national weather service.

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Stormlines Tracks: NOAA, ECMWF, Environment Canada · 12Z run

Full forecast
Through Thu 3 p.m. GMT+9