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Storm · Forecast to formEast Asia

A new low could form southeast of Tokyo on Saturday night

Tokyo — Could pass near Tokyo Sat night; 1 in 10 forecasts bring it within 160 km.

Updated Thurs., Nov. 12, 6:41 a.m. GMT+9 · 101 forecast tracks from NOAA, ECMWF and Environment Canada: high

Tokyo — Could pass near Tokyo Sat night; 1 in 10 forecasts bring it within 160 km.

Quick answers

As of the Wed 11 Nov 12Z model run · updated Thurs., Nov. 12, 6:41 a.m. GMT+9

Where will the North Pacific low east of Japan form?
Forecasts that develop it have the centre forming about 210 kilometres southeast of Tokyo on Saturday night. The most likely path takes it about 290 kilometres west of Adak by Tuesday night, Nov. 17.
When will the North Pacific low east of Japan be closest to Tokyo?
Most likely Saturday, Nov. 14, around 11 p.m. GMT+9. Across the forecasts the comes between Sat 3 p.m. and Sun 5 a.m. GMT+9. Most forecasts pass the centre 140–850 kilometres southeast of Tokyo.
What is the chance it passes within 160 kilometres of Tokyo?
11%: 1 in 10 forecasts bring the storm’s centre within 160 kilometres of Tokyo. Elsewhere: Unalaska 15%. Rain, wind and coastal flooding can reach well beyond 160 kilometres from the centre.
How much rain could Tokyo get while the North Pacific low east of Japan passes?
From Thu 3 a.m. (when the forecast’s rain totals start) to Sun 9 a.m. GMT+9, the end of the window when its centre is closest to Tokyo, the middle of NOAA’s 31 GEFS forecasts brings almost no rain or melted snow to Tokyo; fewer than 1 in 10 bring 13 mm. By Sat 3 p.m., when that window opens, the middle forecast has almost none yet. That is all the rain in that time, not only the North Pacific low east of Japan’s, from one model (GEFS) on a coarse grid; local official forecasts can differ. Tokyo: rain and wind this week →
How sure is the forecast?
Path certainty: high. 101 of 185 show the storm, and they broadly on its early path.
Do the AI and physics models agree?
Largely, yes. Chance within 160 kilometres of Tokyo: AI ensembles (AIFS ENS, AIGEFS) 10%, physics ensembles (GEFS, ECMWF ENS, GEPS) 13%. By model: GEFS 10%, ECMWF ENS 18%, AIFS ENS 12%, AIGEFS 6%, GEPS 5%. By Monday night the AI ensembles’ middle track is about 80 kilometres northeast of the physics ensembles’. At its deepest, the AI ensembles take it to about 962 and the physics ensembles to about 960 mb.
Will the North Pacific low east of Japan become a bomb cyclone?
62% of forecasts (6 in 10) deepen it fast enough to count as a (a pressure fall of roughly 24 in 24 hours, adjusted for latitude).

New to these maps? Read how to read a spaghetti map, or see the week’s rain and wind around the world on the globe.

What we know

Where it forms. The forecasts that show it have the centre taking shape about 210 kilometres southeast of Tokyo on Saturday night, at about 1,016 .

How sure. 101 of 185 show the storm, and they broadly on its early path.1

How strong. It is still strengthening: forecasts deepen it to about 957 by Wednesday afternoon, Nov. 18. Six in 10 forecasts make it a , deepening about 24 millibars or more in a day.

What’s uncertain

Whether it forms. 101 of 185 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 Tokyo, most forecasts put the between 140 and 850 kilometres away, most likely Saturday 11 p.m.

Later on. The forecasts fan out after Sunday. By Thursday night, Nov. 19, the is about 1,700 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.

Rain and wind this week in Tokyo and Unalaska.

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

ModelTracksStatus
NOAA
19 of 3112Z
arrived 4 h 18 min ago
Latest run
ECMWF
36 of 5112Z
arrived 25 min ago
Latest run
ECMWF
27 of 5112Z
arrived 3 h 7 min ago
Latest run
NOAA
16 of 3112Z
arrived 1 h 33 min ago
Latest run
Environment Canada
3 of 2112Z
arrived 4 h 35 min ago
Latest run

Also tracking

  1. North Pacific low west of British ColumbiaLikely to pass 20–210 km S of Anchorage Wed night; 7 in 10 forecasts bring it within 160 km
  2. North Atlantic lowLikely to pass 15–130 km from A Coruña Fri night; 9 in 10 forecasts bring it within 160 km
  3. Southern Ocean lowVery deep low bottoming out near 950 mb Wed night, in the Southern Hemisphere; all 185 forecasts show it
  4. Southern Ocean lowVery deep low bottoming out near 954 mb Wed night, in the Southern Hemisphere; all 185 forecasts show it
  5. South Atlantic lowVery deep low in the Southern Hemisphere, near 958 mb now and filling; all 185 forecasts show it
  6. See all 24 storms →

Notes

  1. Forecast tracks from the 12Z model run: GEFS (31), ECMWF ENS (51), AIFS ENS (51), AIGEFS (31), 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 9 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 Stormlines from the model fields.
  9. Reading these maps: , or the illustrated guide to spaghetti models. The week’s rain, wind and temperature everywhere: the Stormlines globe.
  10. How often these forecasts turn out right: the season’s forecast check, AI vs physics.
  11. Stormlines storm ID: L-2026-2807.

Stormlines draws every storm the world’s ensemble forecasts can see: tracks from NOAA (GEFS and the AI ensemble AIGEFS), ECMWF (ENS and the AI ensemble AIFS) and Environment Canada (GEPS), updated as each model run lands. Coastlines and place names from Natural Earth; sea areas from IHO Sea Areas, version 3 (Flanders Marine Institute, marineregions.org, CC BY 4.0; modified: simplified, some islands removed, names edited).

Not an official forecast. For warnings and decisions, follow your national weather service.

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Stormlines Tracks: NOAA, ECMWF, Environment Canada

Full forecast
Through Fri 3 a.m. GMT+9