A new low could form northwest of Osaka on Sunday morning

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 southeast of Japan form?

Forecasts that develop it have the centre forming about 290 kilometres northwest of Osaka, over the Sea of Japan on Sunday morning. The most likely path takes it about 280 kilometres north of Adak by Wednesday morning, Nov. 18.

When will the North Pacific low southeast of Japan be closest to Tokyo?

Most likely Sunday, Nov. 15, around 6 p.m. GMT+9. Across the forecasts the closest pass comes between Sun 8 a.m. and Sun 10 p.m. GMT+9. Most forecasts pass the centre 80–3,550 kilometres north 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 11%. 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 southeast of Japan passes?

From Thu 3 a.m. (when the forecast’s rain totals start) to Mon 3 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 0.4 mm of rain and melted snow to Tokyo; fewer than 1 in 10 bring 13 mm. By Sun 3 a.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 southeast 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: low. 88 of 185 ensemble forecasts show the storm, and they disagree on where it goes. The forecasts shifted about 130 kilometres northwest since the previous run.

Do the AI and physics models agree?

Largely, yes. Chance within 160 kilometres of Tokyo: AI ensembles (AIFS ENS, AIGEFS) 16%, physics ensembles (GEFS, ECMWF ENS, GEPS) 7%. By model: GEFS 6%, ECMWF ENS 4%, AIFS ENS 24%, AIGEFS 3%, GEPS 14%. By Tuesday morning, Nov. 17 their middle tracks are almost on top of each other. At its deepest, the AI ensembles take it to about 953 mb and the physics ensembles to about 956 mb.

Will the North Pacific low southeast of Japan become a bomb cyclone?

74% of forecasts (7 in 10) deepen it fast enough to count as a “bomb” (a pressure fall of roughly 24 millibars 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.