WPAC: INVEST 91W

[Hayabusa]

91W INVEST 260427 0000 2.8N 163.5E WPAC 15 1009

[Hayabusa]

Traditional NWP models (GFS, Euro) show development near this area, while AI models show little to no development until it reaches near the Marianas
26/12z 1k ensemble from DeepMind

[mrbagyo]

Floater is up

[cycloneye]

The next name and for sure will hear a lot is Hagupit that means to lash or to flog. I see this maybe being a very strong typhoon and may be similar to Sinkalu and also similar track that is the most worrisom part with the Marianas recovering from the past one. And the other part is it will be a high ACE producer for the basin mounting from the 43+ that Sinkalu got.

[cycloneye]

8:30 PM, MON, APRIL 27, 2026 - TROPICAL DISTURBANCE, INVEST 91W, LIKELY TO SLOWLY DEVELOP AS IT DRIFTS WEST-NORTHWESTWARD
Earlier this afternoon (Monday, April 27 2026), a very weak tropical disturbance located near 3.7N 160.9E, southwest of Kosrae, was dubbed Invest 91W by the Joint Typhoon Warning Center (JTWC). The invest is rated sub-low, meaning little development is expected over the next few days. Showers are spread over much of eastern Micronesia, associated with a fragmented Intertropical Convergence Zone (ITCZ) and various trade-wind interactions, as well as the newly-designated Invest 91W. Invest 91W is currently producing scattered to numerous showers and isolated thunderstorms to the south of Pohnpei and Kosrae. This disturbance remains very weak, with fairly typical 15 to 25 mph trade winds to its north and northeast, and 5 to 15 mph west to northwesterlies to its south.
The evolution of Invest 91W remains very uncertain, with ensemble model guidance showing a very broad array of possibilities over the next 7-10 days with little consensus. It is too early to discuss individual deterministic model outcomes, but some ensemble predictions do depict a developing circulation with potential to strengthen into a tropical cyclone, lifting northwest from central or eastern Micronesia over the next week or so, with a track that could pass somewhere near the Marianas. However, confidence on this or any other particular scenario remains very low at this time. As we move forward and 91W becomes better organized, models will come into better alignment in both track and rate of development.
Folks across eastern and central Micronesia should be prepared for periods of heavy showers and strong gusty winds and stay tuned for the potential for a strengthening circulation in the coming week.
Folks across the Marianas should continue monitoring the latest forecast information from weather.gov/gum and for releases from local emergency managers. At the moment, no other actions are needed other than being aware of the current situation.

[Hayabusa]

This may or may not be the disturbance that develops into a TC, models still far apart on which to develop, Euro AI only starts to develop when it's passing the Marianas while GFS develops before reaching the Marianas.

[mrbagyo]

[ljmac75]

Let's hope this one doesn't track over Saipan and Tinian, they're still getting power back. Latest GFS showed it going way east of there but we're still days away from a clear picture.

[Hayabusa]

00z FNV3 and AIFS

[Hayabusa]

Euro AI still weak development assuming this is the disturbance it is developing, while its upcoming V2 upgrade is switching back and forth on development