Post-Tropical Cyclone Sepat (02W) - Tropical Cyclone Advisory #6 (FINAL), 0000 UTC 6/25/25

…Sepat degenerates into a post-tropical remnant low south of the Izu Islands… …This is the last advisory…

Current storm information:

• Position: 32.0°N 139.5°E

• Movement: N at 10 knots (20 km/h)

• Intensity: 30 knots (55 km/h)

• Central pressure: 1004 hPa

Trend:

• The remnant low is forecast to continue weakening during the next 24 hours.

Watches and warnings:

• No land-based watches or warnings are in effect.

Hazards affecting land:

• None.

Discussion:

Convection associated with Sepat completely dissipated shortly after the previous advisory, and Sepat now lies as a fully exposed swirl of low clouds. There are a few puffs of convection well removed far to the south of the center, likely due to convergence associated with the TUTT cell well to the southwest. This convection has proven not to be enough to sustain Sepat as a tropical cyclone, and continued hostile environmental conditions will make it unlikely for convection to return, so Sepat is now a post-tropical remnant low.

The remnant low is forecast to persist for a few days as it moves northward toward Honshu, then turns northeastward. Interaction with a frontal system to the north will likely impart some baroclinic forcing to the system and allow it to regain gale-force winds as it accelerates away from Japan. By this weekend, post-tropical Sepat should quickly be absorbed by a larger extratropical low near the Kuril Islands.

This is the last advisory on Sepat.

Forecast positions and maximum winds

• 00 hrs: 32.0°N 139.5°E – 30 kts Post-tropical/remnant low

• 12 hrs: 33.6°N 139.8°E – 25 kts Post-tropical/remnant low

• 24 hrs: 35.5°N 140.8°E – 25 kts Post-tropical/remnant low

• 48 hrs: 39.5°N 146.0°E – 30 kts Post-tropical/extratropical

• 72 hrs: 44.0°N 153.5°E – 35 kts Post-tropical/extratropical

• 96 hrs: 48.0°N 156.0°E – 35 kts Post-tropical/extratropical

• 120 hrs: Absorbed by larger extratropical low