Severe thunderstorms in northern Minnesota

July 26th, 2021 |
GOES-16 “Red” Visible (0.64 µm) images (top) and “Clean” Infrared Window (10.35 µm) images (bottom), with plots of SPC Storm Reports [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images (top) and “Clean” Infrared Window (10.35 µm) images (bottom), with plots of SPC Storm Reports [click to play animation | MP4]

1–minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images and “Clean” Infrared Window (10.35 µm) images (above) include time-matched plots of SPC Storm Reports produced by supercell thunderstorms that moved east-southeastward across northern Minnesota during the afternoon and early evening hours on 26 July 2021. Severe reports included a tornado at 2213 UTC and hail as large as to 3.0 inches in diameter at 2334 UTC. These storms developed near and north of a warm/stationary frontal boundary (surface analyses).

Tropical Storm Nepartak approaches Japan

July 26th, 2021 |
MIMIC microwave estimates of Total Precipitable Water, 1800 UTC on 26 July 2021 (Click to enlarge)

As the games of the 2021 Olympics progress, a weakening Tropical Storm Nepartak is moving over coastal waters to the east of Honshu, the main island of Japan. The Total Precipitable Water imagery, above, from MIMIC TPW, shows a plume of moisture wrapped around the circulation center. Himawari-8 Clean Window infrared (10.41 µm) imagery, below , from the Himawari-8 Target scene (courtesy of JMA; here’s a link to more JMA satellite imagery), shows the progression of the storm.

Himawari-8 Band 13 Clean Window Infrared (10.41 µm) imagery, 1712 – 2327 UTC, 26 July 2021 (Click to animate)

The forecast from the Joint Typhoon Warning Center (JTWC) as of 1800 UTC has the weakening storm backing into northern Honshu (forecast track; it’s also available from JMA). As of 2300 UTC, the center of Nepartak had moved north to Tokyo’s latitude, and convective bands on the west side of the storm are affecting areas around Tokyo, Yokohama, Sagami Bay and Chiba prefecture. Interests in Japan should monitor closely the progress of this storm.


Visible imagery from shortly after sunrise on Tuesday 27 July in Japan shows the storm to the east of Japan; very little convection is within the storm center.

Himawari-8 Visible Image (0.64 µm), 0024 UTC 27 July 2021

Metop-A overflew Japan at around 1040 UTC on 27 July. Scatterometry (source) showed the wind structure of the storm very nicely.

MetopA Scatterometer winds, 1041 UTC on 27 July 2021 (Click to enlarge)