Twin Typhoons in the western Pacific

August 17th, 2015 |

Himawari-8 10.35 µm IR images [click to play animated GIF]

Himawari-8 10.35 µm IR images [click to play animated GIF]

Himawari-8 captured the trek of Typhoons Goni (on the left) and Atsani (on the right) as they moved across the central Pacific Ocean on Monday 17 August 2015 (animation also available here as an mp4). Goni has passed through the northern Mariana Islands and is forecast to fluctuate in intensity as it moves towards Asia. Atsani’s predicted path is towards the northwest; it is forecast to intensify to a Category 5 Super Typhoon. Both storms are moving across very warm ocean waters (Goni, Atsani), and deep layer wind shear values are low (below). Sea Surface Ttemperature and Wind Shear products are available from the CIMSS Triopical Cyclones site.

Satellite-derived Wind Shear over the Pacific Ocean, 1800 UTC 17 August 2015 [click to enlarge]

Satellite-derived Wind Shear over the Pacific Ocean, 1800 UTC 17 August 2015 [click to enlarge]

Late in the day on 17 August, a comparison of MTSAT-2 infrared (10.8 µm) and DMSP SSMIS microwave (85 GHz) imagery of Category 3 Typhoon Atsani around 2232 UTC (below) showed a rather ragged-looking eye on the infrared image and evidence of a eyewall replacement cycle (ERC) occurring on the microwave image. The ERC process often indicates that a change in tropical cyclone intensity will soon take place.

MTSAT-2 infrared (10.8 µm) and DMSP SSMIS microwave (85 GHz) images of Typhoon Atsani [click to enlarge]

MTSAT-2 infrared (10.8 µm) and DMSP SSMIS microwave (85 GHz) images of Typhoon Atsani [click to enlarge]

What is remarkable in this case of “twin typhoons” in the West Pacific basin is that the MIMIC-TC product indicated that both Atsani and Goni were undergoing ERCs at about the same time (below).

MIMIC-TC product for Typhoon Atsani [click to enlarge]

MIMIC-TC product for Typhoon Atsani [click to enlarge]

MIMIC-TC product for Typhoon Goni [click to enlarge]

MIMIC-TC product for Typhoon Goni [click to enlarge]

A multi-day YouTube animation of Himawari-8 10.35 µm infrared imagery shows the upscale development of Goni and Atsani in the central Pacific. The loop runs from 13 August through 1200 UTC on 18 August.