Tropical Depression 31W 2026

Live tracking map, satellite, radar, and forecasts of Tropical Depression 31W 2026 near the Northern Mariana Islands. Current wind speed 55km/h. Max 185km/h.

31W is located 543 km north-northeast of Andersen Air Force Base, and has tracked westward at 26 km/h (14 knots) over the past 6 hours. Maximum significant wave height is 4 meters (13 feet).

Over the past 6 hours, 31W has transitioned to a due westward trajectory, steered by the more zonally oriented lower-level flow axis of the subtropical ridge to the northeast due to shallow vortex depth.

Forecast models agree that over the next 6 to 12 hours, the ridge axis will amplify into a more northwest-southeast orientation, allowing 31W to resume a northwestward trajectory; however, a more zonal westward near-term trajectory remains possible if the vortex remains decoupled.

Translational speeds are forecast to remain relatively stable over the next 24 hours before gradually decelerating as the subtropical ridge center propagates eastward and the steering gradient relaxes.

After 36 hours, the passage of a mid-latitude shortwave trough to the north will begin to erode the ridge, with a col expected to develop south of Japan.

In 60 hours, 31W will approach this col and rapidly decelerate as it enters the weak steering environment. Simultaneously, a strong low-level northeasterly cold surge will advect out of the East China Sea and into the Philippine Sea.

In 3 days, the leading edge of the surge flow will impinge upon 31W, while aloft the system remains positioned within the col-induced weak steering pattern, inducing a gradual poleward drift. Concurrently, in the deep-layer flow pattern, an extension of the subtropical ridge will bifurcate into a separate near-equatorial ridge southwest of Guam, imparting a westerly deep-layer steering influence on 31W.

The combination of low-level convergence along the cold frontal boundary and the deep-layer westerly steering flow will accelerate 31W east-northeastward over the next 3 to 5 days.

Regarding intensity, as long as deep easterly shear persists, the system will intensify gradually at a climatological rate of approximately one Dvorak T-number per day. Wind shear is forecast to abate in around 36 hours, which should facilitate rapid vertical vortex alignment and subsequent accelerated intensification, though the official forecast remains just below explicit rapid intensification (RI) thresholds.

Favorable thermodynamic and dynamic conditions persist over the next 3 days, supporting a peak intensity of 185 km/h (100 knots), before rapidly increasing mid-latitude westerly shear, dry air entrainment, and decreasing sea surface temperatures induce a sharp weakening trend after 4 days.

Deterministic track guidance is in fair agreement over the next 3 days, with significant track divergence emerging at 3 days. Cross-track spread is low over the next 60 hours, before rapidly increasing to 389 km in 3 days as the system reaches the synoptic inflection point, where all consensus members agree the system will recurve northeastward.

The GFS is positioned on the southern boundary of the guidance envelope over the next 3 days, while the EC-AIFS and ECMWF reside on the northern boundary.

After 3 days, cross-track spread remains relatively constrained; however, along-track spread increases dramatically. The GFS and NAVGEM show a very slow east-southeastward drift after 3 days, followed closely by GALWEM.

The ECMWF, GEFS, ECEPS, WindBorne experimental model, and the consensus mean advect the system northeastward at a moderate pace, while the data-driven AI models, led by the operational Google DeepMind (GDM) and EC-AIFS, accelerate northeastward at translational speeds exceeding 95 km/h (50 knots). This generates an extreme along-track spread exceeding 1,500 nautical miles between the GFS and EC-AIFS.

Ensemble guidance is similarly dispersed, depicting significant intra-ensemble spread even though the majority of ensemble means agree on the synoptic trajectory.

Individual members of the experimental JTWC super ensemble range in their the next 5 days positions from near Luzon to far east of Japan, spanning well over 1,500 nautical miles.

The official JTWC forecast is placed with low confidence near the GEFS mean, ECEPS mean, and WindBorne cluster, and slightly slower than the deterministic ECMWF.

Intensity guidance is in generally good agreement on the overall timing and evolution of the intensity profile, but exhibits significant spread regarding peak intensity, which ranges from a minimum of 100 km/h (55 knots) (COTC and SHIPS-NAVGEM) to a maximum of 205 km/h (110 knots) (HAFS-A, HWRF, and CTCX).

The GDM solution resides close to the consensus at 150–165 km/h (80–90 knots).

The JTWC intensity forecast is placed just below the consensus mean over the next 2 days, blends toward the HWRF peak at 3 days, and subsequently follows the gradual weakening trend of the mesoscale dynamical models after 3 days.