Subtropical Storm Debby

August 7th, 2018 |

“Red” Visible (0.64 µm) images from GOES-17 (left) and GOES-16 (right) [click to play animation | MP4]

* GOES-17 images shown here are preliminary and non-operational *

“Red” Visible (0.64 µm) images from GOES-17 and GOES-16 (above) showed the circulation and convective banding associated with Subtropical Storm Debby in the Atlantic Ocean on 07 August 2018.

Deep-layer wind shear analysis from the CIMSS Tropical Cyclones site (below) indicated that Debby was in an environment of low shear.

GOES-16

GOES-16 “Red” Visible (0.64 µm) image, with deep-layer wind shear analysis [click to enlarge]

Hurricane John

August 7th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector “Red” Visible (0.64 µm) images from the AOS site (above) showed the circulation of Hurricane John as it was intensifying from a Category 1 to a Category 2 storm off the west coast of Mexico on 07 August 2018. Several tropical overshooting tops could be seen in the animation.

GOES-16 Upper-level Water Vapor (6.2 µm), Mid-level Water Vapor (6.9 µm), Low-level Water Vapor (7.3 µm) and “Clean” Infrared Window (10.3 µm) images (below) revealed an interesting gravity wave that was propagating northward away from the center of John. This wave appeared to perturb the cloud tops — perhaps via vertical mixing — leading to a slight warming of the colder cloud-top infrared brightness temperatures as the wave passed. The appearance and behavior of this wave was very similar to another observed in Nebraska, Colorado and Kansas on 22 July.

GOES-16 Upper-level Water Vapor (6.2 µm, top left), Mid-level Water Vapor (6.9 µm, top right), Low-level Water Vapor (7.3 µm, bottom left) and

GOES-16 Upper-level Water Vapor (6.2 µm, top left), Mid-level Water Vapor (6.9 µm, top right), Low-level Water Vapor (7.3 µm, bottom left) and “Clean” Infrared Window (10.3 µm, bottom right) images [click to play MP4 animation]

Another item of interest was the circulation of weakening Tropical Storm Ileana being absorbed by the larger circulation of intensifying Hurricane John — this process was illustrated by 3-hourly 850 hPa relative vorticity analyses derived from GOES-15 (GOES-West) satellite winds (below). Similar results were seen at the 700 hPa, 500 hPa and 200 hPa pressure levels.

3-hourly analyses of 850 hPa relative vorticity [click to enlarge]

3-hourly analyses of 850 hPa relative vorticity [click to enlarge]

===== 08 August Update =====

Visible images from GOES-15, GOES-14, GOES-17 and GOES-16 [click to play animation | MP4]

Visible images from GOES-15, GOES-14, GOES-17 and GOES-16 [click to play animation | MP4]

GOES-15 (GOES-West), GOES-14, GOES-17 and GOES-16 (GOES-East) Visible images (above) showed 4 views of Hurricane John after it had diminished to a Category 1 storm on 08 August.

Note that the GOES-15 and GOES-14 Visible images do not appear as bright as those from GOES-17 and GOES-16 — prior to the GOES-R Series of satellites, the performance of visible detectors degraded over time, leading to imagery that appeared more dim as the Imager instrument aged. Visible detectors on the new ABI instrument benefit from on-orbit calibration to remedy this type of degradation.

* GOES-17 images shown here preliminary and non-operational *