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Hurricane Kristy reaches Category 5 intensity

By Scott Bachmeier •

1-minute GOES-18 Red Visible (0.64 µm, left) and Clean Infrared Window (10.3 µm, right) images with an overlay of GLM Flash Points, from 1331-1600 UTC on 23 October [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Visible and Infrared imagery of Hurricane Kristy in the East Pacific Ocean on 23 October (above) highlighted a well-defined eye, with GLM-indicated lightning activity increasing within the inner eyewall. Cloud-top infrared brightness temperatures in the -80s C (shades of violet to purple) were apparent at times. Kristy reached Category 4 intensity as of the 2100 UTC advisory from NHC.

A closer view of GOES-18 Visible images (below) revealed low-altitude mesovortices within the eye.

1-minute GOES-18 Red Visible (0.64 µm) images with an overlay of GLM Flash Points, from 1601-2100 UTC on 23 October [click to play MP4 animation]

Hurricane Kristy was moving through an environment characterized by low values of deep-layer wind shear, as seen in an analysis from the CIMSS Tropical Cyclones site (below) — a factor which favored its rapid intensification.

GOES-18 Infrared images, with an overlay of 2000 UTC deep-layer wind shear contours and streamlines

===== 24 October Update =====

1-minute GOES-18 Red Visible (0.64 µm, left) and Clean Infrared Window (10.3 µm, right) images with an overlay of GLM Flash Points, from 1802-2300 UTC on 24 October [click to play MP4 animation]

On 24 October, 1-minute GOES-18 Visible and Infrared imagery (above) again displayed a well-defined eye, with GLM-indicated lightning activity increasing within the inner eyewall — and cloud-top infrared brightness temperatures in the -80s C (shades of violet to purple) were apparent at times. Kristy continued to further intensify, becoming a Category 5 hurricane as of the 2100 UTC advisory from NHC.

In a closer view of GOES-18 Visible images (below), distinct low-altitude mesovortices were once again seen within the eye.

1-minute GOES-18 Red Visible (0.64 µm) images with an overlay of GLM Flash Points, from 1802-2300 UTC on 24 October [click to play MP4 animation]

Earlier in the morning, when Kristy was still a Category 4 hurricane, a Synthetic Aperture Radar (SAR) image at 1401 UTC (below) indicated that a derived maximum wind speed of 130 knots was present in the NE quadrant of the eyewall (source).

RCM-3 SAR image at 1401 UTC on 24 October [click to enlarge]

Categories: GLM, GOES-18, Lightning, SAR, Satellite winds, Tropical cyclones