Severe Tropical Storm Krosa (12W) – Tropical Cyclone Advisory #18: 0000 UTC 1 August 2025

Krosa moving northward and getting better organized.

Author

Will Weaver
July 31, 2025

…Krosa moving northward and getting better organized…

Himawari-9 visible satellite image (Weathernerds)

Current storm information:

  • Position: 32.6°N 141.9°E

  • Movement: N at 8 knots (15 km/h)

  • Intensity: 50 knots (95 km/h)

  • Central pressure: 975 hPa

Trend:

  • Fluctuations in intensity are possible during the next 24 hours.

Watches and warnings:

  • There are no land-based watches or warnings in effect.

Hazards affecting land:

  • Although Krosa is forecast to remain offshore, there is still a chance it could pass close enough to Honshu to produce tropical storm conditions along the southeastern coast. U.S. military interests can get additional information from the Stars & Stripes Pacific Storm Tracker: https://www.stripes.com/theaters/asia_pacific/storm_tracker/

Discussion:

F-17 SSMIS 91GHz microwave satellite image (RAMMB/CIRA)

Krosa is starting to get better organized as it moves over warmer SSTs. A rather intense band of convection has developed and is in the process of wrapping its way around the center, although dry air entrainment continues to be an inhibiting factor. Despite the dry air, microwave satellite imagery indicates a nearly complete (and large) eyewall feature has redeveloped around the center. Krosa’s outflow has become somewhat restricted due to the presence of an upper-level trough that is beginning to impinge upon the system. The intensity remains 50 kts, and is mainly held back by a wide range of Dvorak fixes (T3.0 to T3.5) and rather low CIMSS ADT and D-PRINT estimates. This estimate may be conservative given Krosa’s improved structure.

As previously mentioned, Krosa is now being influenced by an upper-level trough located over Honshu, and it has turned almost due north. Because of this, the forecast track has been nudged quite a bit to the east of the previous one, since Krosa will soon reach the northwestern edge of a high pressure ridge over the west central Pacific. This new track keeps Krosa further away from Honshu, and significant effects there are becoming less likely. By Saturday, Krosa should turn sharply east-northeastward and accelerate into the mid-latitude westerlies. Some fluctuations in intensity are expected during the next 72 hours or so, but by Monday Krosa will be moving over cooler waters and interacting with a frontal system. This should result in Krosa becoming a post-tropical cyclone by Tuesday just before it exits the Western Pacific basin.

Forecast positions and maximum winds

  • 00 hrs: 32.6°N 141.9°E – 50 kts

  • 12 hrs: 34.2°N 141.5°E – 55 kts

  • 24 hrs: 36.0°N 142.5°E – 55 kts

  • 48 hrs: 38.7°N 150.3°E – 55 kts

  • 72 hrs: 41.4°N 161.0°E – 50 kts

  • 96 hrs: 42.7°N 168.2°E – 40 kts Post-tropical/extratropical

  • 120 hrs: 44.0°N 176.5°W – 30 kts Post-tropical/extratropical

JMA forecast map