Hurricane Olaf

October 20th, 2015 |
Advanced Dvorak Technique (ADT) intensity estimate plot for Hurricane Olaf

Advanced Dvorak Technique (ADT) intensity estimate plot for Hurricane Olaf

A plot of the Advanced Dvorak Technique (ADT) intensity estimate for Hurricane Olaf (above) showed that the storm went through a period of rapid intensification during the 19-20 October 2015 period, reaching Category 4 strength. The National Hurricane Center noted that Olaf became the 6th major hurricane in the eastern North Pacific during the 2015 season, and that this was is the farthest south (9.9º N latitude) that a major hurricane had formed in that ocean basin since reliable records began in 1971 (discussion archive: NHC | CPHC).

4-km resolution GOES-15 (GOES-West) 10.7 µm Infrared channel images during the period of rapid intensification (below) revealed that cloud-top IR brightness temperatures were quite cold (in the -80º to -90º C range, violet colors) early in the day on 19 October, but then warmed a bit into the -70º to -80º C range (black to white shades) on 20 October as the eye became more well-defined.

GOES-15 Infrared (10.7 µm) images [click to play animation]

GOES-15 Infrared (10.7 µm) images [click to play animation]

A 375-meter resolution Suomi NPP VIIRS Infrared (11.45 µm) image at 10:23 UTC on 20 October (below) hinted at the presence of mesovortices within the eye of Hurricane Olaf.

Suomi NPP VIIRS Infrared (11.45 µm) image [click to enlarge]

Suomi NPP VIIRS Infrared (11.45 µm) image [click to enlarge]