Subtropical storm in the South Pacific

May 27th, 2021 |

GOES-17

GOES-17 “Red” Visible (0.64 um) images [click to play animation | MP4]

GOES-17 (GOES-West) “Red” Visible (0.64 um) images (above) showed the development of a subtropical storm in the South Pacific Ocean (just northeast of New Zealand) on 27 May 2021. Surface analyses from the New Zealand Met Service are available here.

GOES-17 “Clean” Infrared Window (10.3 um) images (below) highlighted the curved band of cold-topped convection wrapping into the deepening storm.

GOES-17 "Clean" Infrared Window (10.3 um) images [click to play animation | MP4]

GOES-17 “Clean” Infrared Window (10.3 um) images [click to play animation | MP4]

A NOAA-20 Infrared Window (11.45 um) image viewed using RealEarth (below) showed a higher resolution view of the band of cold clouds wrapping into the system at 1206 UTC.

NOAA-20 Infrared Window (11.45 um) image [click to enlarge]

NOAA-20 Infrared Window (11.45 um) image [click to enlarge]

With ample illumination from the Moon — in the Waning Gibbous phase, at 98% of Full — a Suomi NPP VIIRS Day/Night Band (0.7 um) image (below) provided a high-quality “visible image at night” at 1256 UTC (12:56 am NZST).

Suomi NPP VIIRS Day/Night Band (0.7 um) image [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 um) image [click to enlarge]

Suomi NPP ATMS Microwave (183.3 GHz) image

Suomi NPP ATMS Microwave (183.3 GHz) image (credit: Derrick Herndon, CIMSS) [click to enlarge]

A Suomi NPP ATMS Microwave (183.3 GHz) image (above) portrayed the spiral band wrapping into the core of the system at 1256 UTC, while a cross section of Suomi NPP ATMS Brightness Temperature anomaly (below) depicted the deep warm core (shades of green) characteristic of the subtropical cyclone.

Cross section of Suomi NPP ATMS Brightness Temperature anomaly [click to enlarge]

Cross section of Suomi NPP ATMS Brightness Temperature anomaly (credit: Derrick Herndon, CIMSS) [click to enlarge]

Blowing dust across Mongolia and China

May 6th, 2021 |

Himawari-8 Dust RGB images [click to play animation | MP4]

Himawari-8 Dust RGB images [click to play animation | MP4]

JMA Himawari-8 Dust RGB images (created using Geo2Grid) covering the 48-hour period from 21 UTC on 04 May to 21 UTC on 06 May 2021 (above) revealed multiple plumes of blowing dust (brighter shades magenta/pink) which originated over parts of Mongolia — and were then transported southeastward and eastward across northeastern China.

Surface analyses from the Korean Meteorological Agency (below) showed an impressive pressure gradient between a midlatidude cyclone (moving southeastward from Mongolia into China) and high pressure moving southward behind it. Some of the airborne dust was entrained into the circulation of this low pressure system.

Surface analyses during the period from 21 UTC on 0 May to 21 UTC on 06 May [click to enlarge | MP4]

Surface analyses during the period from 21 UTC on 04 May to 21 UTC on 06 May [click to enlarge | MP4]

VIIRS True Color RGB mages from Suomi NPP and NOAA-20 viewed using RealEarth (below) showed the hazy arc of blowing dust along the trailing cold front (south of the cyclone in northeastern China) on 6 May.

VIIRS True Color RGB mages from Suomi NPP and NOAA-20 [click to enlarge]

VIIRS True Color RGB mages from Suomi NPP and NOAA-20 [click to enlarge]

Tropical Cyclone Joba makes landfall in Tanzania

April 24th, 2021 |

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

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

US Space Force EWS-G1 Infrared (10.7 µm) images (above) showed Tropical Cyclone Jobo as it moved west-northwestward across the Indian Ocean during the 23-24 April 2021 period, eventually making landfall in Tanzania as a weakening Tropical Depression. Jobo was traversing warm sea surface temperatures during its westward trek.

A sequence of VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP as viewed using RealEarth (below) provided higher-resolution views of the various stages of convection associated with Jobo during the 22-24 April period.

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

Cold cloud tops associated with Tropical Storm Surigae in the West Pacific

April 15th, 2021 |

JMA Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

JMA Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

2.5-minute interval rapid scan JMA Himawari-8 Infrared Window (10.4 µm) images (above) revealed intermittent cloud-top infrared brightness temperatures of -100ºC and colder (red pixels embedded within yellow-to-black inner cores) — with the coldest being -101.7ºC at 1342 UTC — within the Central Cold Cover (CCC) pattern of Tropical Storm Surigae on 15 April 2021.

A zoom-in of NOAA-20 VIIRS Infrared Window (11.45 µm) imagery at 1644 UTC as viewed using RealEarth (below) also showed 2 clusters of red -100ºC and colder pixels, with a minimum of -103.6ºC (incidentally, the coldest pixels on the 1644 UTC Himawari-8 Infrared image were -96ºC). About an hour and 15 minutes after this NOAA-20 image, Surigae was upgraded to a Category 1 typhoon (the first typhoon of the 2021 season in the West Pacific basin).

NOAA-20 VIIRSI Infrared Window (11.45 µm) image at 1644 UTC [click to enlarge]

NOAA-20 VIIRS Infrared Window (11.45 µm) image at 1644 UTC [click to enlarge]

A plot of 12 UTC rawinsonde data from Yap Island showed that the coldest air temperature was -84.7ºC at 100 hPa (16.7 km) — so an overshooting top of -100ºC or colder indicated a significant vertical ascent above the tropopause.

Plot of 12 UTC rawinsonde data from Yap Island [click to enlarge]

Plot of 12 UTC rawinsonde data from Yap Island [click to enlarge]