Tropical Storm Halong (28W) – Tropical Cyclone Advisory #2: 0000 UTC 5 October 2025

…Depression strengthens into Tropical Storm Halong as it creeps toward Iwo Jima…

Current storm information:

• Position: 24.6°N 142.8°E

• Movement: W at 3 knots (5 km/h)

• Intensity: 35 knots (65 km/h)

• Central pressure: 1002 hPa

Trend:

• Additional strengthening is forecast during the next 24 hours.

Discussion:

Tropical Depression 28W has fairly quickly gotten better organized despite battling some strong westerly shear. Convection has increased near the circulation center, which is currently tucked just under the western edge of the convective envelope. Despite the system’s sheared appearance, it has strong equatorward outflow sustaining its central cold cover (CCC) with very cold cloud tops. Microwave satellite imagery indicates that the CCC pattern may be transitioning into a curved band pattern as convection has begun developing into discrete bands wrapping into the center from the south and east. Dvorak fixes range from T2.0 to T2.5 while CIMSS’ automated estimates are all around 35 kts, so the system is now Tropical Storm Halong with an intensity of 35 kts.

The forecast is challenging because basically every model seems to have a different idea of what will happen with the subtropical ridge currently steering Halong. Although the models almost universally indicate rapid intensification during the next few days, and they all amplify a deep-layer trough extending from an extratropical low in the Sea of Okhotsk, which will work to erode the ridge. The issue is that the models do not agree on where the ridge will weaken, and therefore where Halong will recurve. The deterministic GFS, GFS ensemble, and Google DeepMind AI models all show a recurvature occurring well to the east of the Ryukyu Islands and south of Japan, while the deterministic ECMWF and ECMWF ensemble tracks show either no recurvature at all (with a track straight west into Taiwan) or a recurvature well to the west. The HAFS-A is somewhere in between. The forecast track being used in this advisory is the JMA one, as it is about in the middle of the guidance. However, this forecast is of fairly low confidence, and it is still possible that an intense typhoon could be near the Ryukyu Islands toward the end of the forecast period.

Forecast positions and maximum winds

• 000 hrs: 24.6°N 142.8°E – 35 kts

• 012 hrs: 24.7°N 142.0°E – 45 kts

• 024 hrs: 25.0°N 140.7°E – 55 kts

• 048 hrs: 25.4°N 137.0°E – 75 kts

• 072 hrs: 26.9°N 133.4°E – 100 kts

• 096 hrs: 28.2°N 132.4°E – 115 kts

• 120 hrs: 29.3°N 132.4°E – 105 kts