Typhoon Halong (#28W) – Tropical Cyclone Advisory #5: 1200 UTC 6 October 2025

Halong becomes a typhoon. Expected to rapidly intensify beginning later tonight as it remains well to the south and east of Japan.

Author

Will Weaver
October 06, 2025

…Halong becomes a typhoon… …Expected to rapidly intensify beginning later tonight as it remains well to the south and east of Japan…

Replace this image with a current satellite image of the storm (Source)

Current storm information:

  • Position: 26.1°N 140.1°E

  • Movement: NW at 7 knots (10 km/h)

  • Intensity: 70 knots (130 km/h) [Category 1]

  • Central pressure: 978 hPa

Trend:

  • Rapid strengthening is forecast during the next 24 hours. Halong could become a Category 2 typhoon by midday on Tuesday and a Category 3 typhoon on Tuesday evening.

Watches and warnings:

  • Fleet Activities Yokosuka is under TCCOR 4.

Hazards affecting land:

  • Halong is not expected to be a direct threat to land, but it could produce rough seas, heavy surf, and life-threatening rip currents along the southern and southeastern coasts of Honshu on Wednesday and Thursday.

  • U.S. military interests in Japan can get additional information via the Stars & Stripes Pacific Storm Tracker: https://www.stripes.com/theaters/asia_pacific/storm_tracker/

Discussion:

WSFM MWI 37GHz microwave satellite image

Halong appears to be fighting off the shear that has plagued it, and it is now beginning to respond to a much more favorable environment. Convection has begun to increase in coverage, with convective hot towers beginning to flare south of the center and wrap around the eastern periphery of an increasingly well defined eye. Halong’s outflow channels have become much better defined, likely due to the deep-layer trough to the north being in a more favorable position to enhance Halong’s poleward outflow. All in all, Halong appears to be poised to enter a rapid intensification phase, and this is also reflected by the telltale cyan ring present on 37GHz microwave satellite imagery. The intensity is increased to 70 kts, hedged between consensus T4.0 Dvorak fixes and a CIMSS D-PRINT estimate of 78 kts. 

Although the rapid intensification guidance seems to suggest otherwise, much of the available dynamical and ensemble model guidance indicates that Halong will begin to explosively intensify later tonight. The environment should be quite favorable with decreasing shear, very warm SSTs, and a continued favorable trough interaction enhancing Halong’s poleward outflow channel. At about the same time, the same trough is expected to erode the ridge centered to the northeast, which will result in Halong executing a sharp recurvature motion to the north, then the east-northeast. The model guidance is in fairly strong agreement on this motion, and Halong is expected to become a super typhoon well to the south of Japan on Wednesday before being swept up into the mid-latitude westerlies. Halong should accelerate rapidly to the east-northeast through the end of the week. 

Although it will be over warm waters and moving very quickly (so the effects of increasing shear should be somewhat minimized), Halong is expected to become entangled within the trough with a sting jet feature forming within the circulation by the end of the week, and Halong is expected to become an exceptionally powerful hurricane-force post-tropical cyclone at the end of the forecast period.

Forecast positions and maximum winds

  • 000 hrs: 26.1°N 140.1°E – 70 kts

  • 012 hrs: 26.1°N 140.1°E – 95 kts

  • 024 hrs: 28.0°N 136.9°E – 120 kts

  • 048 hrs: 31.1°N 137.5°E – 135 kts

  • 072 hrs: 33.0°N 143.5°E – 130 kts

  • 096 hrs: 33.9°N 155.2°E – 115 kts

  • 120 hrs: 37.4°N 171.4°E – 100 kts Post-tropical/extratropical

JMA forecast map