Kompasu skirts to the north of Luzon

October 11th, 2021 |
Himawari-8 clean window infrared (band 13, 10.4 µm) imagery, 0232 – 1502 UTC on 11 October 2021

Severe Tropical Storm Kompasu moved westward just north of the island of Luzon in the Philippines on 11 October. The Himawari-8 Target Sector clean window infrared (Band 13, 10.4 µm) imagery, above, from 0232 – 1502 UTC (Imagery courtesy JMA; imagery available here), shows deep convection becoming more organized as the storm center moved.

Moderate wind shear that had been affecting Kompasu slowly relaxed in the 24 hours before the storm moved north of Luzon, as shown in the wind shear tendency map shown below (imagery obtained from this link at the CIMSS Tropical Website). Shear over/around the storm has been relaxing.

Wind shear tendency, 1500 UTC 10 October 2021 – 1200 UTC 11 October 2021 (click to enlarge)
Wind shear over the western Pacific, 1200 UTC 10 October – 1200 UTC 11 October 2021 (Click to enlarge)

Computed shear (imagery also taken from the CIMSS Tropical Website) is shown in the animation above. Wind shear for both animations above is defined here. A relatively small area of favorable wind shear was near the storm center as Kompasu became better organized in the band 13 imagery above.

Scatterometry imagery, below, from various satellite platforms at this site, tracked the system’s motion from 0100 to 1130 UTC on 11 October, as it moved north of Luzon.

Scatterometer imagery from HY-2B and HY-2C, and from ASCAT A, B and C, between 0100 and 1130 UTC on 11 October (2021)

Kompasu is forecast to move due west across the South China Sea in the next days, affecting the island of Hainan on the 13th before 1200 UTC. (Forecast, from JTWC; Here is a similar plot from JMA). Wind shear is not forecast to relax further in the next days so significant stregthening is not forecast.

Cyclone Shaheen makes landfall in Oman

October 3rd, 2021 |

US Space Force EWS-G1 Infrared Window (10.7 µm) images [click to play animation | MP4]

US Space Force EWS-G1 (formerly GOES-13) Infrared Window (10.7 µm) images (above) showed
Hurricane Shaheen weakening to a Tropical Storm shortly after it made a rare landfall along the coast of Oman on 03 October 2021. The storm exhibited an eye at times as it was a Category 1 Hurricane over the Gulf of Oman. This was likely the first tropical cyclone to make landfall along that coastal portion of Oman since 1890 (Wikipedia).

Meteosat-8 Infrared images, with contours of deep-layer wind shear from the CIMSS Tropical Cyclones site (below) indicated that the storm was moving through an environment of low shear.

Meteosat-8 Infrared images, with contours of deep-layer wind shear [click to enlarge]

Suomi-NPP VIIRS True Color RGB and infrared Window (11.45 µm) images viewed using RealEarth (below) showed the Category 1 Hurricane at 0927 UTC.

Suomi-NPP VIIRS True Color RGB and infrared Window (11.45 µm) images at 0927 UTC [click to enlarge]

1985s Hurricane Gloria

September 27th, 2021 |

Late September of 1985, saw the landfalls of Hurricane Gloria. More information. These NOAA GOES-6 animations are in both the infrared (window) and visible parts of the electromagnetic spectrum.


A color-enhanced GOES-6 infrared loop from September 21-27, 1985.

A still infrared image is from September 25, 1985. Note that cold temperatures are colored yellow, red and black.


A GOES-6 visible loop from September 27, 1985.

A similar loop, as an animated gif. Also see this still image.

A combined visible and infrared GOES-6 Full Disk image from September 27, 1985 at 18 UTC.

A larger Full Disk “sandwich” image from the same time as above.


H/T Brian McNoldy for reminding us of “his storm”:

More on Hurricane Gloria via AMS publications.

NOAA GOES-6 data are via the University of Wisconsin-Madison SSEC Satellite Data Services. McIDAS-X was used the generate the imagery. Of course the current generation of GOES imagers (ABI) provide much improved (spatial, spectral and temporal) imagery. Or see a CIMSS Satellite Blog post on Hurricane Sam.

TROPICS Pathfinder view of super typhoon Mindulle

September 26th, 2021 |
TROPICS Pathfinder 205 GHz imagery, 0545 UTC on 26 September 2021 (Upper Left) and Himawari-8 Band 3 Visible (0.64 µm) Imagery, 0540 UTC on 26 September (Lower Right) (Click to enlarge)

Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) Pathfinder imagery from 0545 UTC on 26 September, when super typhoon Mindulle was near peak intensity, is compared above to Himawari-8 visible(0.64 µm) imagery at about the same time. A separate image links small features in the Pathfinder image to small convective elements that are apparent in the Himawari imagery. Click here to view the TROPICS Pathfinder image with a NOAA-20 true-color image from 0426 UTC.

The pathfinder satellite that provided the microwave data used for the image above is the first in a series of a constellation of low-Earth orbiters; six additional satellites will be launched next year. These are very small satellites, with a size of 10 cm x 10 cm x 36 cm. They weigh in at 5.34 kg / 11.8 pounds! Pathfinder imagery was provided courtesy of the Science Team working with the data. Himawari-8 imagery are courtesy of JMA.

As noted above, NOAA-20 overflew Mindulle at about 0430 UTC. The Advanced Technology Microwave Sounder (ATMS) instrument on NOAA-20 sampled the storm, and imagery (88.2 GHz and 183.3 GHz) with a timestamp of 0435 UTC (from this archive) is shown below. The NOAA-20 orbits over the western Pacific on that day are shown here (from this site). Structures in the Pathfinder imagery at 0545 UTC can be identified in the 0435 UTC ATMS imagery below. A side-by-side comparison of the Pathfinder 205 GHz and NOAA-20 ATMS 183.3 GHz is shown at bottom.

NOAA-20 ATMS imagery from channel 16 (88.2 GHz) and channel 18 (183.3 GHz), 0435 UTC , 26 September 2021 (Click to enlarge)
NOAA-20 ATMS 183.3 GHz imagery, 0435 UTC on 26 September (left) and Pathfinder 205 GHz imagery, 0545 UTC on 26 September (right) (Click to enlarge)