Tropical Storm Neoguri (#25W) – Tropical Cyclone Advisory #2: 1200 UTC 18 September 2025

…Small tropical depression in the far eastern part of the basin becomes Tropical Storm Neoguri…

Current storm information:

• Position: 23.6°N 163.5°E

• Movement: W at 7 knots (10 km/h)

• Intensity: 35 knots (65 km/h) 

• Central pressure: 1004 hPa

Trend:

• Some strengthening is forecast during the next 24 hours.

Discussion:

The tiny tropical depression in the far eastern part of the basin has continued to get better organized since the first advisory. The convection has rapidly consolidated and is wrapping quite tightly into a well-defined circulation center. The system really is quite small as the circulation is difficult to resolve on scatterometer imagery, though its location can be estimated by following low cloud lines on shortwave infrared satellite imagery. The system has very good radial outflow in all quadrants, and all in all the system is quite impressive for where it is. The intensity is increased to 35 kts based on a 1041 UTC ASCAT pass, and JMA has upgraded the system to Tropical Storm Neoguri.

Neoguri is in a fairly favorable environment of low shear and very warm SSTs, and given its small size, there is a chance it could intensify quite rapidly during the next few days. The models are still having trouble resolving Neoguri, again because of its small size, and the GFS-based guidance continues to show a rather weak system during the next few days. Meanwhile, the ECMWF and Google DeepMind ensembles indicate significant strengthening through the end of the forecast period. Neoguri is likely to become a typhoon by Sunday, and it could be quite intense - the wind values in the forecast track below are higher than the JMA forecast after conversion to 1-minute winds.

Neoguri is forecast to move generally westward through Saturday, when it is expected to encounter a break in the subtropical ridge caused by an upper-level trough. At this point, confidence in the forecast breaks down because the ensembles are split on whether the trough causes Neoguri to recurve to the northeast or leaves it behind entirely - another consequence of its small size. The current forecast indicates recurvature over open waters, but there is a small chance recurvature may not occur right away.

Forecast positions and maximum winds

• 00 hrs: 23.6°N 163.5°E – 35 kts

• 12 hrs: 24.0°N 161.3°E – 45 kts

• 24 hrs: 24.7°N 158.8°E – 55 kts

• 48 hrs: 25.6°N 154.6°E – 70 kts

• 72 hrs: 27.9°N 150.4°E – 80 kts

• 96 hrs: 31.0°N 150.4°E – 90 kts

• 120 hrs: 31.7°N 152.2°E – 100 kts