Tropical Depression 06W – Tropical Cyclone Advisory #2: 1200 UTC 11 July 2025

…Tropical Depression 06W not moving very much… …Expected to begin accelerating northward on Saturday…

Current storm information:

• Position: 25.1°N 140.0°E

• Movement: Nearly stationary

• Intensity: 30 knots (55 km/h)

• Central pressure: 1004 hPa

Trend:

• Some strengthening is forecast during the next 24 hours, and the depression could become a tropical storm on Saturday.

Watches and warnings:

• There are no land-based watches or warnings in effect.

Hazards affecting land:

• Interests along the eastern coast of Honshu should monitor the progress of this system.

Discussion:

Tropical Depression 06W is not a very well organized system. The system is generating quite a bit of convection, but it is displaced far to the south and east of the circulation center by strong (25-30 kts) northwesterly shear associated with an upper-level low situated well to the west. This shear occasionally leaves the center exposed, but at the moment the center is continuing to generate bursts of convection. Although most of the convection is well removed from the center, it is fairly well organized with discrete banding features. There are not any indications the system is producing tropical storm force winds yet, so the intensity remains 30 kts, hedged between Dvorak fixes ranging from T1.5 to T2.0 from KNES, RJTD, and PGTW, and CIMSS ADT and D-PRINT estimates of 31 and 27 kts respectively.

TD 06W is currently embedded in a pocket of weak steering currents due to the presence of an upper-level trough. This trough is expected to lift out on Saturday, which will both cause TD 06W to start moving northward and slightly decrease the shear impacting it, which will allow for strengthening. 06W is forecast to become a tropical storm on Saturday, and it will likely reach peak intensity by late Sunday or early Monday as it passes just east of Honshu. Although the forecast track keeps 06W off the coast, some of the model guidance suggests the center could actually make landfall on Honshu near or east of Tokyo on Monday. Some of the guidance, namely the HAFS-A and HWRF models, also strengthens 06W more than current forecasts indicate, and both of the aforementioned models actually bring 06W to typhoon strength before reaching Japan. This seems unlikely at the moment given the unfavorable environment, but it remains a distinct possibility.

Whether 06W makes landfall or not, by Monday it should become involved with an extratropical low over the Sea of Japan and quickly transition into a post-tropical cyclone east of Hokkaido by Monday night or Tuesday. The post-tropical cyclone should merge with the other low shortly after.

Forecast positions and maximum winds

• 00 hrs: 25.1°N 140.0°E – 30 kts

• 12 hrs: 25.4°N 140.4°E – 35 kts

• 24 hrs: 26.3°N 140.9°E – 45 kts

• 48 hrs: 31.0°N 141.9°E – 55 kts

• 72 hrs: 39.4°N 142.9°E – 45 kts Post-tropical/extratropical

• 96 hrs: 48.9°N 152.6°E – 45 kts Post-tropical/extratropical

• 120 hrs: Absorbed by extratropical low