Tuesday, September 20, 2011

Typhoon Roke Update #13

Typhoon Roke has slightly weakened and is now down to a Category 2 typhoon. Maximum sustained winds have decreased to 175kph gusting to 215kph. Roke was last located approximately  260km southeast of Miyazaki or about 920km southwest of Tokyo. Roke is moving northeastward at 15kph.

VIS Image from NRLMRY

The VIS image above shows the well-defined eye with a well-developed central dense overcast. The microwave image below taken by SSMIS shows the intense eyewall and another ring of convection trying to develop. Generally, when typhoons exhibit concentric rings it usually signifies that an Eyewall Replacement Cyclone is imminent. It is possible we could see Roke undergo an EWRC tonight.


This radar image from JMA also shows the location of Roke's center with respect to Japan. The eye has actually moved out of Japan's radar coverage although you can still see the outer rain bands affecting Kyushu and Shikoku. Fortunately, we haven't seen any reports of strong winds just yet and we expect it to remain that way. The wind field doesn't really expand that far from the center.

Radar from JMA, for more images click HERE

Please do note that a frontal boundary is bringing very heavy rain across much of Japan. These rains can be accompanied by thunderstorms as well as isolated tornadoes. There has actually been a reported sighting of a tornado touchdown near Nagoya. Level 1 Tornado Warnings continue to exist across Shikoku, Kinki, and Chubu Regions. Please remain VIGILANT!

Going back to Roke, our forecast has not really changed significantly although we have shifted the track slightly westward. We expect Roke to maintain typhoon intensity even after landfall. It will remain south of Japan tonight but is expected to pass very closely south of the Kii Peninsula very early tomorrow morning (Japan Time). We are then forecasting it to make landfall in either Aichi or Shizuoka Prefecture tomorrow. Roke will then pass across Chubu Region, particularly near the Tokyo Metropolitan Area. It will then rapidly weaken to a tropical storm as it interacts with land and increasing wind shear. Roke will continue traversing Eastern Honshu passing through Kanto and Eastern Tohoku Region. The storm is expected to exit Honshu by early Thursday morning and should accelerate northeastward, passing south of Hokkaido.

Personal Forecast  (NOT OFFICIAL)

This Typhoon Risk Map highlights the possible effects that Roke will bring to Japan for September 20, 2011 (Tuesday). The data is supported by forecasts among agencies and computer models. Please remember this is NOT OFFICIAL and you must still consult JMA for the official warnings and advisories for your area.

We'll have another update tomorrow morning. Please stay safe!!
Issued (0930 UTC) 530pm PhT 092011

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