Tropical Storm Danas (05W/Bising) - Tropical Cyclone Advisory #6: 0000 UTC 7/7/25

…Danas dramatically weaker and less organized after crossing Taiwan… …Heavy rainfall and gusty winds continue…

Current storm information:

• Position: 25.5°N 121.4°E

• Movement: NE at 14 knots (25 km/h)

• Intensity: 45 knots (85 km/h)

• Central pressure: 990 hPa

Trend:

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

Watches and warnings:

• Typhoon warning (Taiwan): Keelung, Taipei, New Taipei, Taoyuan, Hsinchu, Hsinchu County, and Yilan County

Hazards affecting land:

• Danas is expected to produce extremely heavy rainfall over portions of Taiwan and southeastern China, mostly along the coast of the Taiwan Strait, beginning late tonight into Monday morning. In addition, strong tropical storm or typhoon conditions are possible along those coasts late tonight through Monday evening. Storm total rainfall of over 500 mm is possible in portions of Taiwan through Tuesday.

• The remnants of Danas are expected to produce extremely heavy rainfall over much of southern and eastern China and Taiwan beginning on Tuesday. This rainfall will likely cause widespread severe flooding.

Discussion:

Danas made landfall near Tainan, Taiwan at around 1600 UTC with winds of 90 kts. Since then, Danas has quickly traversed the western portion of the island and is now over the far southwestern East China Sea. Interaction with land has more or less blown Danas’s structure apart - the central dense overcast has fragmented into multiple clusters of flaring convection, with a large band of convection located well to the east in an area of convergence associated with an upper-level trough. The circulation is very poorly defined and appears to consist of two large swirls of low clouds rotating around one another, with most of the convection located near the easternmost of the two swirls. The intensity has taken a nosedive and is now estimated to be 45 kts, based on available Dvorak estimates of T3.0 from PGTW and RJTD, and a 39 kt estimate from CIMSS D-PRINT.

Danas is currently being steered northeastward by deep-layer southerly flow associated with a ridge centered over South Korea, and it should gradually turn northward during the next few hours. Although SSTs in the East China Sea are fairly warm, moderate westerly shear combined with the poor state of Danas’s circulation will likely preclude any redevelopment. By Tuesday, a monsoon gyre is expected to begin developing in the East China Sea near the Ryukyu Islands, and the cyclonic flow into this gyre will capture Danas fairly quickly, causing it to quickly loop westward and make landfall in southeastern China. Danas will likely continue to meander near the coast on Tuesday and Wednesday before the circulation dissipates within the gyre flow.

Forecast positions and maximum winds

• 00 hrs: 25.5°N 121.4°E – 45 kts

• 12 hrs: 27.3°N 122.0°E – 45 kts

• 24 hrs: 28.4°N 122.0°E – 40 kts

• 48 hrs: 27.7°N 119.0°E – 30 kts inland

• 72 hrs: 26.5°N 116.0°E – 20 kts post-tropical/remnant low/inland

• 96 hrs: Dissipated