Severe Cyclone Winston in the South Pacific Ocean

February 20th, 2016

Himawari-8 Visible (0.64 µm) images [click to play animation]

Himawari-8 Visible (0.64 µm) images [click to play animation]

JMA Himawari-8 Visible (0.64 µm) images (above) revealed the presence of mesovortices within the large and well-defined eye of Category 5 Severe Cyclone Winston as the storm approached the largest Fiji islands of Vanua Levu and Viti Levu during the 19-20 February 2016 period.

A longer animation of Himawari-8 Infrared Window (10.4 µm) images (below) showed a degradation of the eye as it moved over the slightly rugged terrain of Viti Levu, suggesting a slight decrease of intensity (ADT plot | SATCON wind | SATCON pressure). However, when Winston initially made landfall on that island with sustained winds of 185 mph it tied as the second strongest landfalling tropical cyclone on record — and Winston could also be the strongest tropical cyclone on record in the Southern Hemisphere (Capital Weather Gang blog). The images include plots of surface observations from Nadi (NNFN) and Nausori (NNFA) on the island of Viti Levu.

Himawari-8 Infrared Window (10.4 µm) images [click to play animation]

Himawari-8 Infrared Window (10.4 µm) images [click to play animation]

Nighttime comparisons of Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images showed Cyclone Winston as the storm was well east of Fiji on 18 February, and just west of Fiji on 20 February (below). With abundant illumination from the Moon in the Waxing Gibbous phase (from 82 to 95% of full), the “visible image at night” capability of the Day/Night Band was effectively demonstrated.

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) images [click to enlarge]

As Winston began to decrease in intensity from a Category 4 to a Category 2 storm after 12 UTC on 21 February, a large eye was still present in DMSP-16 SSMIS Microwave (85 GHz) imagery from the CIMSS Tropical Cyclones site (below).

DMSP-16 SSMIS Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

DMSP-16 SSMIS Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images [click to enlarge]

Leave a Reply