2023-07-30 12:00 UTC

Khanun (Philippine name Falcon) is located 656 km southeast of Kadena Air Base, Okinawa, Japan, and has moved northward at 17 km/h (9 knots) over the past 6 hours.?

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Khanun will move more northwestward under the steering influence of the building subtropical ridge to the northeast toward Okinawa, passing 122 km southwest of Kadena Air Base on 01/17:00 UTC prior to drifting slowly into the East China Sea.?

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After 3 days, a secondary subtropical ridge, currently anchored in the gulf of Pohai, will compete for steering and force a quasi-stationary (QS) storm motion in the East China Sea.?

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The highly favorable environment will fuel rapid intensification to a peak of 230 km/h (125 knots) in 36 hours. Afterward, subsidence caused by a mid-latitude trough to the north and behind the current subtropical ridge will prevent further intensification.?

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In the East China Sea, increasing wind shear and cooling sea surface temperatures due to upwelling induced by the system QS motion will more rapidly erode the system down to 120 km/h (65 knots) in 5 days.?

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Forecast models are in overall good agreement but now with a more pronounced spread to 574 km in 3 days with GFS the extreme right-of-track outlier deviating from the model pack as early as the next 36 hours.?

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After 3 days, all members show a slow poleward trajectory, albeit in a very wide spread spanning over 926 km in 5 days. In view of this, there is medium confidence in the JTWC forecast and intensity tracks up to 3 days then low confidence afterward.?

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Maximum significant wave height is 15.2 meters (50 feet).

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Information provided by the Joint Typhoon Warning Center (JTWC).

2023-07-31 09:00 UTC

Khanun (Philippine name Falcon) is located 563 km southeast of Kadena Air Base, and has moved north-northwestward at 17?km/h (9 knots) over the past 6 hours.

Khanun will move west-northwestward over the next 3 days passing to the south of?Okinawa?with a peak intensity of 220-230?km/h (120-125 knots) in 24 hours.

Gradual weakening should occur as the system passes Okinawa with more pronounced weakening as it slows and stalls northwest of Okinawa and upwells cooler water.

Due to the system's large size and close proximity to Okinawa after closest point of approach, there remains a high probability of gale-force winds or higher if the system drifts closer within the weak steering environment.

As discussed below, there is high uncertainty (low confidence) in the JTWC forecast track after 2 days. Deterministic model guidance remains in good agreement only over the next 2 days with a 76 km cross-track spread at 36 hours and a 94 km cross-track spread at 2 days lending high confidence to this portion of the JTWC forecast track.

JTWC forecast tracks have remained within a tight, 93 km envelope just to the south of Okinawa over the past four days. However, along-track speeds have remained inconsistent resulting in a significant change in the closest point of approach timing over the past 12 hours.

After 2 days, both deterministic and probabilistic guidance continue to show a very large spread (433 nautical miles spread at 4 days and a 952 km spread at 5 days) and a high degree of uncertainty due to the rapid weakening of the steering ridge to the north. This rapid weakening of the steering ridge is due to a combination of the westerlies across the Korean Peninsula and the unusually large size of Khanun, which is currently estimated at a 700-780 nautical miles diameter.

After 2 days, Khanun will be positioned within a competing steering environment with a?subtropical ridge?to the east and another weak subtropical ridge to the west thus a slow, possibly erratic track over the next 5 days. This uncertain scenario is evident in the 31/00:00 UTC ECMWF (EPS) and GFS (GEFS) ensemble solutions.

Maximum significant wave height is 14.6?meters (48?feet).

Information provided by the Joint Typhoon Warning Center (JTWC).