Super Typhoon Choi-Wan (15W)

September 17th, 2009 |

MTSAT-1R IR images

MTSAT-1R IR images

MTSAT-1R 10.7 µm IR images (above) showed Super Typhoon Choi-Wan (17W) as it reached Category 5 intensity over the western North Pacific Ocean during the 15 September 16 September 2009 period. The eye of the typhoon was quite large (which moved just to the south of Pagan in the Northern Mariana Islands), with a very cold rings of convection seen during the various eyewall replacement cycles (as also seen on this MIMIC animation). A time series of the Advanced Dvorak Technique (ADT) intensity estimate from the CIMSS Tropical Cyclones site is shown below.

Advanced Dvorak Technique intensity estimates for Choi-Wan

Advanced Dvorak Technique intensity estimates for Choi-Wan

MODIS IR image

Terra MODIS IR image (14 September)

A pair of 1-km resolution MODIS images show the dramatic change in satellite appearance of Choi-Wan, from one with a ragged eye surrounded by cloud tops as cold as -87º C (darker purple color enhancement) on 14 September (above) to more of a classic  annular structure with a large and well-defined eye on 15 September (below).

MODIS IR image

Aqua MODIS IR image (15 September)