Tropical Storm Bailu (13W) – Tropical Cyclone Advisory #6: 0300 UTC 4 August 2025

…Bailu likely to become post-tropical on Tuesday…

Current storm information:

• Position: 37.3°N 150.6°E

• Movement: ENE at 20 knots (35 km/h)

• Intensity: 35 knots (65 km/h)

• Central pressure: 995 hPa

Trend:

• Little change in strength is forecast during the next 24 hours.

Discussion:

Bailu is already beginning to move over cooler waters, and convection associated with it has decreased significantly during the past several hours, and is now limited to a small area just to the east of the center. Another area of convection is located well to the northeast of the center and appears to be a result of Bailu becoming entangled within a baroclinic zone extending from the now post-tropical Krosa well to the northeast. The intensity remains 35 kts, based on recent HYSAT scatterometer data.

Although Bailu is still over waters of about 25-26°C, it is already becoming embedded within the frontal boundary extending from Krosa, and as such it is likely to lose the rest of its tropical characteristics during the next 24 hours. Bailu will likely become a post-tropical cyclone itself on Tuesday. Unlike Krosa, Bailu will not have very much baroclinic support, and as such it will likely weaken after completing extratropical transition, with most model guidance dissipating the system just before it leaves the basin on Thursday.

Forecast positions and maximum winds

• 00 hrs: 37.3°N 150.6°E – 35 kts

• 12 hrs: 37.7°N 153.6°E – 35 kts

• 24 hrs: 38.1°N 156.6°E – 35 kts Post-tropical/extratropical

• 48 hrs: 40.5°N 161.5°E – 30 kts Post-tropical/extratropical

• 72 hrs: 43.7°N 168.7°E – 30 kts Post-tropical/extratropical

• 96 hrs: Dissipated