The Active Atlantic Basin in August and September

October 4th, 2017 |

ABI “Clean Window” Infrared (10.3 µm) Image, 1800 UTC on 8 September 2017, showing Katia, Irma and Jose, from left to right (Click to animate as a YouTube Video)

The YouTube link, above, shows the GOES-16 “Clean Window” (10.3 µm) Infrared Imagery over the Atlantic, showing the evolution of Hurricanes Franklin through Maria, from 7 August through 1 October. (The original mp4 video (250 Meg) is available.)

GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing

September 2017: a record-setting month in terms of Atlantic tropical cyclone ACE

October 4th, 2017 |

* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

The Accumulated Cyclone Energy (ACE) for September 2017 set a new record for any month over the North Atlantic basin:

Two significant contributors to this record ACE value were long-lived and very intense Hurricane Irma and Hurricane Maria.

Hurricane Irma – Ace: 66.6 – Duration: 13 Days

Montage of Hurricane Irma GOES-13 infrared images, with and without storm track/intensity [click to view]

Montage of Hurricane Irma GOES-13 infrared images, with and without storm track/intensity [click to view]

One noteworthy statistic of Hurricane Irma: during its 3 days and 3 hours as a Category 5 hurricane (above), the storm had an intensity of 160 knots or 185 mph for 37 consecutive hours — which set a new world record. GOES-16 “Clean” Infrared Window (10.3 µm) images during this period of 185 mph intensity (below) showed a well-defined eye, with cold cloud-top infrared infrared brightness temperatures (occasionally -80ºC or colder, denoted by the violet color enhancement) within the adjacent eyewall region.

GOES-16 Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

GOES-16 Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

Hurricane Maria – Ace: 44.6 – Duration: 14 Days

Montage of Hurricane Maria GOES-13 infrared images, with and without storm track/intensity [click to view]

Montage of Hurricane Maria GOES-13 infrared images, with and without storm track/intensity [click to view]

One noteworthy aspect of Hurricane Maria was its intensification to a Category 5 storm on 18 September (above) — just before making landfall on the island of Dominica — and less than 48 hours before making landfall over southeastern Puerto Rico as a high-end Category 4 storm. GOES-16 Infrared Window (10.3 µm) images at 1-minute (pre-landfall) and 30-second (post-landfall) time intervals (below) showed that while the eye of Maria quickly eroded as the tropical cyclone moved northwestward across the island and interacted with its rugged terrain, deep convection of the eyewall region persisted over much of Puerto Rico during the transect. Note that the last hourly surface observations from Roosevelt Roads (TJNR) and San Juan (TJSJ) were from 04 UTC and 09 UTC, respectively — after which times power and communications to weather equipment (such as the San Juan radar) were lost.

GOES-16 Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

GOES-16 Infrared Window (10.3 µm) images, with hourly surface reports plotted in yellow [click to play MP4 animation]

Hurricane Jose – Ace: 42.2 – Duration: 17 Days

Montage of Hurricane Jose GOES-13 infrared images, with and without storm track/intensity [click to view]

Montage of Hurricane Jose GOES-13 infrared images, with and without storm track/intensity [click to view]

Although not as intense as Irma or Maria, the long duration of Hurricane Jose allowed it to achieve an ACE value nearly as high.

Individual storm montage images are available here on the CIMSS Tropical Cyclones site.