Tropical Depression 04W – Tropical Cyclone Advisory #3: 1200 UTC 9 April 2026

…Tropical storm warnings and typhoon watches issued for portions of Chuuk State…

Current storm information:

• Position: 8.5°N 151.4°E

• Movement: WSW at 5 knots (10 km/h)

• Intensity: 30 knots (55 km/h)

• Central pressure: 999 hPa

Trend:

• Some strengthening is forecast during the next 24 hours, and the depression will likely become a tropical storm later tonight.

Discussion:

Tropical Depression 04W has continued to become better organized as it slowly creeps away from Chuuk. Despite CIMSS analyzing some moderate easterly shear affecting the system, TD 04W’s convective banding has become much better defined, with simulated and actual microwave satellite imagery depicting this banding wrapping into the circulation center from the west. The convective structure is a little bit lopsided, with most of the convection situated to the west of the center. While many of the Dvorak-based estimates suggest tropical storm intensity, with most agencies reporting T2.5 Dvorak fixes and automated CIMSS ADT, AiDT, and D-PRINT estimates averaging to about 35 kts, recent scatterometer data and surface observations do not indicate that 04W is producing tropical storm force winds yet, so the intensity remains 30 kts.

The forecast is a bit clearer tonight, as the models are in much better agreement now that there is a trackable vortex associated with 04W. Most of the model guidance indicates a track toward the west-northwest, although the GFS continues to be on the southwestern end of the guidance while Google DeepMind is on the eastern end. The current forecast track is closest to the ECMWF, HAFS-A, and HWRF models and more or less splits the difference. On this track, 04W is expected to pass just to the southwest of Guam on Monday or Tuesday.

Late this weekend, environmental conditions are expected to become much more favorable for development as shear is expected to decrease while 04W moves over SSTs that are quite warm for April. At about the same time, a strong upper-level trough is expected to amplify off the coast of Japan and provide an excellent outflow channel for 04W, which will enable rapid intensification. Despite the differences in their tracks, the models almost unanimously indicate explosive intensification toward the end of the forecast period, and RIPA rapid intensification guidance suggests a high probability (63.7%) of an increase of 65 knots in the next 72 hours. The forecast below is not quite that aggressive, but it is very possible that 04W could be near super typhoon intensity as it makes its close approach to Guam.

Forecast positions and maximum winds (1-min)

• 000 hrs: 08.5°N 151.4°E – 30 kts 55 km/h 

• 012 hrs: 08.5°N 150.9°E – 40 kts 75 km/h 

• 024 hrs: 08.4°N 150.3°E – 50 kts 95 km/h 

• 048 hrs: 09.0°N 149.5°E – 60 kts 110 km/h 

• 072 hrs: 10.4°N 147.5°E – 85 kts 155 km/h 

• 096 hrs: 12.2°N 144.5°E – 110 kts 205 km/h 

• 120 hrs: 13.8°N 141.9°E – 125 kts 230 km/h