DISCUSSION: As of earlier today, Super Typhoon Jebi was making global headlines as it continued to impress both meteorological and non-meteorological communities alike as a powerful tropical cyclone spinning across part of the Western Pacific Ocean basin. As shown in the animated satellite imagery above (courtesy of the Himawari-8 satellite imager), there was very robust convection propagating both within and right around the edge of the eye wall and the central dense overcast region associated with Jebi. As a point of clarification, the central dense overcast within a tropical cyclone is the region wherein there is most often found to be the strongest thunderstorm activity wrapped around the immediate center and inner core regions of a given tropical cyclone. It goes without saying that Super Typhoon Jebi will remain to be a very legitimate and serious threat for the island nation of Japan in the coming days as it will most likely remain at least the equivalent of a major hurricane from the Tropical Atlantic basin.
As far as neat features go in association with Super Typhoon Jebi, one of the more interesting features currently being observed in association with Jebi is the consistent generation of gravity waves outward from the eye much earlier in the day on Friday morning (i.e., local time over in the Western Pacific Ocean basin). Gravity wave generation within the inner core region of intense tropical cyclones often occurs as a result of more rapid inner core pressure gradient changes and/or fluctuations. As a result of these more rapid inner core pressure changes occurring, the tropical cyclone dynamical response is sometimes visually observed in the form of gravity waves which are essentially vertical undulations in atmospheric flow. In a physical sense, gravity waves are effectively an atmospheric equilibrium-based response where the atmosphere is seeking an energetically-balanced state but is unable to do so within the inner-core of an intense tropical cyclone. Therefore, within the upper-most cloud deck associated with the inner core of more intense tropical cyclones there is often found to be at least a brief period during which gravity waves emanate from the eye wall and outward radially in all directions for at least 20 to 40 nautical miles or so (depending on the intensity of the given pressure gradient within a given storm near the time of peak intensity).
It goes without saying that when gravity wave generation happens within the core of intense tropical cyclones for longer periods of time, this is especially when one should be concerned and attentive about future changes in intensity as well as forward track of a given tropical cyclone.
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© 2018 Meteorologist Jordan Rabinowitz