Tropical Depression Matmo (27W) – Tropical Cyclone Advisory #12 (FINAL): 1200 UTC 6 October 2025

Matmo weakens to a tropical depression as it continues to straddle the China-Vietnam border. This is the last advisory.

Author

Will Weaver
October 06, 2025

…Matmo weakens to a tropical depression as it continues to straddle the China-Vietnam border… …This is the last advisory…

Himawari-9 infrared satellite image (Weathernerds)

Current storm information:

  • Position: 23.0°N 106.3°E

  • Movement: WNW at 11 knots (20 km/h)

  • Intensity: 30 knots (55 km/h)

  • Central pressure: 996 hPa

Trend:

  • Rapid weakening is forecast during the next 24 hours. Matmo will likely become a remnant low later tonight and dissipate on Tuesday.

Watches and warnings:

  • There are no coastal watches or warnings in effect.

Hazards affecting land:

  • Heavy rainfall associated with Matmo and its remnants will continue to pose a widespread severe flooding threat in southern China, northern Vietnam, and northeastern Laos during the next few days. For additional details, refer to products from your local weather office.

Discussion:

Matmo’s circulation continues to be fairly well defined despite being quite far inland over rugged terrain. However, dry continental air has continued to become entrained within it, and most of the convection near the center has dissipated. Matmo does still have bands of convection located around the periphery of the circulation, although cloud tops within these bands are beginning to warm as the main inflow band moves inland over Vietnam. An ASCAT pass from around 0300 UTC indicated that a large swath of 35 to 40 kt winds was still occurring over the Gulf of Tonkin, but given Matmo’s decay and distance traveled since landfall, it does not appear likely tropical storm force winds are still occurring, so Matmo is downgraded to a 30 kt depression.

With Matmo’s inflow now located over land, it should not be long before its remaining convection dissipates, and this will probably happen in less than 12 hours. With Matmo expected to rapidly decay and dissipate within the next 24 hours, this is the last advisory. Matmo should spin down into a remnant low later tonight before the circulation opens up into a trough on Tuesday.

This is the last advisory on Matmo.

Forecast positions and maximum winds

  • 000 hrs: 23.0°N 106.3°E – 30 kts 

  • 012 hrs: 24.0°N 105.0°E – 20 kts Post-tropical/remnant low inland

  • 024 hrs: Dissipated