The Pacific storm season has produced two notable events in just a few days: Super Typhoon In-fa developed an unusually large eye, and the remnants of Typhoon Champi transitioned into an extratropical storm that headed toward Alaska.

A typhoon's eye is the central region of relatively calm, clear air surrounded by the eyewall, where the strongest winds are concentrated. That In-fa reached such a wide eye diameter is striking because eye size does not grow indefinitely with storm intensity: equally powerful systems can have narrow, well-defined eyes. The structure seen in In-fa points to a particular storm configuration that satellite meteorologists are watching closely.

Champi, meanwhile, illustrates another common process in the life of a tropical cyclone. As it moves over colder waters and toward higher latitudes, a typhoon loses its energy source —the ocean's heat and moisture— and begins to transform into an extratropical storm, with frontal structure and winds spread over a much larger area. In that phase, Champi's remnants headed toward Alaska, where such systems can bring strong winds and significant swell.

Both cases were observed by weather satellites, key tools for tracking cyclones over the open Pacific, where direct monitoring is sparse. Following these phenomena helps improve models that predict track and intensity, an active area of work given that the internal structure of typhoons —including eye size— remains difficult to reproduce accurately in simulations.