Super Typhoon Guchol (Butchoy) Update #13

Note: For our latest video update click HERE. It contains extensive analysis and forecast for Guchol as well as an update on a developing disturbance in the South China Sea. Invest 92W, just east of Hainan, could develop into a Tropical Storm in the next 2 days.

Super Typhoon Guchol (Bagyong Butchoy) continues to move away from the Philippines and is now nearing the Japanese Islands. The eye was last located approximately 580km east southeast of Basco, Batanes or about 820km south of Okinawa. Maximum sustained winds remain at 240kph with gusts of up to 295kph. STY Guchol is currently moving north northwestward at 25kph.

IR Image from NRLMRY

The eyewall replacement cycle seems to have begun 6 hours ago. Despite that, the storm has maintained classic typhoon signature with the well-defined eye and good outflow channels. A series of microwave images (not shown here) depict double eyewall forming around the core with the outer eyewall expected to "kill" the inner eyewall in the next 24 hours. EWR cycles usually weaken a storm, however, improving poleward outflow is partially offsetting that at the moment. With that said, we expect Guchol to maintain its current intensity for the next 24 to 36 hours.

If you are living in Okinawa or the nearby Japanese Islands, you must have your storm preparations ready by this time. We expect stormy conditions to begin late Monday morning as the outer rain bands from Guchol are expected to affect the region. Worst conditions are forecast to begin Monday afternoon and could last throughout the night as Guchol passes somewhere between 150 to 200km east of Okinawa.. By that time, typhoon force winds of 140 to 180kph are possible! Furthermore, rainfall amounts of 200mm or more could fall in a short span of time. Conditions will begin to improve for Okinawa by Tuesday morning. For the areas north such as Amami, tropical storm winds could still continue throughout Tuesday afternoon.

Forecast Track (NOT OFFICIAL!)

After passing east of the Ryukyu Islands, Guchol will quickly weaken as sea surface temperatures decrease and wind shear increase. Nevertheless, we still expect it to maintain typhoon status as it moves 200-300km south of Shikoku and skirt the southern coast of Kansai Region in Honshu. Forecast models are split whether or not Guchol makes landfall in Japan. For now, we are leaning at a possible brush through the Kanto Plains by early Wednesday morning. There is a medium chance of Guchol moving across the Tokyo Area as a weakening typhoon by that time. Please stay tuned for further developments.

We'll have another update tomorrow morning. Continue to keep monitoring the storm, especially if you are within its path. For those living in Mainland Japan, I suggest to start making preparations now even though the storm is still 2 to 3 days away. For Okinawa, always coordinate with the local authorities and JMA for the latest and OFFICIAL warnings and forecasts for your specific area. Stay safe!
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Issued (10 UTC) 6pm PhT 061712