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Smog with light winds over Kyushu

True Color imagery over western Japan, above, from three JPSS Satellites (from the NASA Worldview site) show a region with a hazy signature that appears to originate over Kyushu’s main cities of Kumamoto and Fukuoka. Winds at this time are relatively light, as evidenced by the NOAA-21 image, shown below, that includes a dark... Read More

True Color imagery from NOAA-21 (ca. 0422 UTC), Suomi-NPP (ca. 0448 UTC) and NOAA-20 (ca. 0510 UTC) , 30 June 2025 (Click to enlarge)

True Color imagery over western Japan, above, from three JPSS Satellites (from the NASA Worldview site) show a region with a hazy signature that appears to originate over Kyushu’s main cities of Kumamoto and Fukuoka. Winds at this time are relatively light, as evidenced by the NOAA-21 image, shown below, that includes a dark region within the sun glint (see this blog post for another discussion of diagnosing light winds within areas of sun glint).

NOAA-21 True Color imagery ca. 0422 UTC on 30 June 2025 (Click to enlarge). A region of likely light winds is circled.

Advanced Scattermeter (ASCAT) data from a fortuitous overpass from Metop-B (source), shown below, confirms the region of very light winds around Kyushu.

ASCAT winds from MetopB, 1229 UTC on 30 June 2025 (Click to enlarge)

Aerosol Optical Depth (scaled from 0-5) computed from Suomi NPP and NOAA-20 is shown below. The haze does not appear to be from active fires based on this animation of shortwave infrared imagery from Himawari-9.

Aerosol Optical Depth imagery (blended from Suomi-NPP and NOAA-20), 30 June 2025 (Click to enlarge)

Air Quality Indices, below, (from this site), show the worst near-surface Air Quality over southern Kyushu. This is a good reminder that satellite detection of AOD views the entire atmosphere — to get the best description of Air Quality, use both surface and satellite detection.

Near-surface Air Quality over southwestern Japan, 30 June 2025 (Click to enlarge)

Editor’s Note: This is my last contribution to the CIMSS Satellite Blog, as I am retiring today after 30 years (plus 1 month, a week and a day) with the University of Wisconsin-Madison. It has been a great honor to talk about beautiful and informative satellite imagery in this space, starting in 2006 with this blog post on Parallax. I hope my writings (1) have been helpful and (2) have been accurate. It’s honestly the best job I could imagine having!

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Tropical Depression 2 becomes Tropical Storm Barry in the far southwestern Gulf of Mexico

1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Infrared and Visible images (above) showed persistent deep convection (with sporadic lightning activity) near the center of circulation of Tropical Depression 2 (TD2), which developed in the Bay of Campeche (just off the coast of Mexico) around 2100 UTC on 28 June 2025. Periodic convective bursts contained... Read More

1-minute GOES-19 Infrared (left) and Visible (right) images with an overlay of GLM Flash Points, from 1601 UTC on 28 June to 0045 UTC on 29 June [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Infrared and Visible images (above) showed persistent deep convection (with sporadic lightning activity) near the center of circulation of Tropical Depression 2 (TD2), which developed in the Bay of Campeche (just off the coast of Mexico) around 2100 UTC on 28 June 2025. Periodic convective bursts contained overshooting tops that exhibited infrared brightness temperatures as cold as -80C (brighter white pixels embedded within darker black regions), but overall the system remained somewhat disorganized throughout the day.

A GOES-19 Visible image at 1619 UTC with an overlay of Metop-C ASCAT winds (below) depicted a surface circulation, with wind speeds in the 20-25 knot range within the southeast quadrant.

GOES-19 Infrared and Visible images at 1619 UTC on 28 June, with an an overlay of Metop-C ASCAT scatterometer winds on the Visible image [click to enlarge]

GOES-19 Infrared images with an overlay of deep-layer wind shear (below) indicated that TD2 was embedded within an environment of high wind shear, which was an unfavorable factor in terms of further intensification.

GOES-19 Infrared images with an overlay of contours and streamlines of deep-layer wind shear at 0100 UTC on 29  June

===== 29 June Update =====

1-minute GOES-19 Infrared and Visible images with an overlay of GLM Flash Points, from 1341-1900 UTC on 29 June [click to play MP4 animation]

By 1500 UTC on 29 June, TD2 had become better organized, and was named Tropical Storm Barry. For a short time, the partially exposed low-level circulation center was evident in 1-minute GOES-19 Visible images (above).

A DMSP-17 SSMIS Microwave image at 1301 UTC (below) showed no evidence of a closed eye structure, with only signatures of convection immediately south and east of the storm center.

DMSP-17 SSMIS Microwave (85 GHz) image at 1301 UTC on 29 June

As was the case during the previous day, TS Barry was still in an unfavorable environment characterized by high values of deep-layer wind shear (below).

GOES-19 Infrared images with an overlay of contours and streamlines of deep-layer wind shear at 1500 UTC on 29 June

On the other hand, the MIMIC Total Precipitable Water product (below) showed abundant moisture in the vicinity of TS Barry, which helped to sustain the development of deep convection near the storm center.

MIMIC Total Precipitable Water product at 1500 UTC on 29 June, with an overly of the position of TS Barry at 1200 UTC

It is interesting to note that TD2 passed over a small patch of slightly warmer Sea Surface Temperature not long before intensifying to become TS Barry (below) — although it’s not clear what role (if any) this played in system intensification.

Sea Surface Temperature at 2233 UTC on 28 June, with an overlay of the position of TS Barry at 1200 UTC on 29 June

Wind Shear, Sea Surface Temperature, MIMIC TPW and DMSP Microwave images were sourced from the CIMSS Tropical Cyclones site.

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Wildfire in the Northwest Territories produces a large pyrocumulonimbus cloud

A cluster of wildfires was burning on both sides of the Northwest Territories / British Columbia border on 28 June 2025 — and 10-minute Full Disk scan GOES-18 (GOES-West) imagery (above) showed that the largest Northwest Territories wildfire produced a sizeable pyrocumulonimbus (pyroCb) cloud, beginning at 2230 UTC. As it drifted... Read More

10-minute GOES-18 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, bottom) images, from 2100 UTC on 28 June to 0520 UTC on 29 June [click to play animated GIF | MP4]

A cluster of wildfires was burning on both sides of the Northwest Territories / British Columbia border on 28 June 2025 — and 10-minute Full Disk scan GOES-18 (GOES-West) imagery (above) showed that the largest Northwest Territories wildfire produced a sizeable pyrocumulonimbus (pyroCb) cloud, beginning at 2230 UTC. As it drifted northward, the cold canopy of the pyroCb expanded along its west-to-east axis — exhibiting cloud-top infrared brightness temperatures in the -50s C (shades of red).

About 1.5 hours prior to pyroCb development, a NOAA-20 VIIRS True Color RGB image visualized using RealEarth (below) revealed the smoke plumes emanating from these wildfires. Significant values of Fire Radiative Power (larger, darker-red circles) were associated with the largest pyroCb-producing wildfire in the Northwest Territories.

NOAA-20 VIIRS True Color RGB image at 2056 UTC on 28 June, with an overlay of Fire Radiative Power for active fires [click to to enlarge]

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Welcome to Summer! (Summer Solstice 2025)

The summer solstice occurred on June 20th this year (2025). The summer solstice is the day with the longest period of daylight and the shortest night of the year in a given hemisphere, and marks the beginning of astronomical summer. In the Northern Hemisphere, it typically falls on June 20... Read More

The summer solstice occurred on June 20th this year (2025). The summer solstice is the day with the longest period of daylight and the shortest night of the year in a given hemisphere, and marks the beginning of astronomical summer. In the Northern Hemisphere, it typically falls on June 20 or 21.

GOES satellite imagery provides a unique view of the earth as we pass through the various seasons. The angle of the shadow at sunrise or sunset (satellite time, or at the satellite nadir point) shows how earth progresses through the seasons from summer solstice to fall equinox. Watch the reflection of the sun migrate through the imagery, in this case from the southern hemisphere to the northern hemisphere in this animation of GOES-East from the winter solstice (Dec 21, 2024) to the summer solstice (Jun 20, 2025).

GOES-East (GOES-16 through Apr 7 and GOES-19 after) Full Disk “CIMSS Natural Color” animation from Dec 21, 2024 to June 20, 2025 at local sunset (23:00 UTC). Click to animate! https://cimss.ssec.wisc.edu/satellite-blog/wp-content/uploads/sites/5/2025/06/GOES19_CIMSSNatColor_Winter2SummerSolstice2025_Sunset.mp4
GOES-West (GOES-18) Full Disk “CIMSS Natural Color” animation from Dec 21, 2024 to June 20, 2025 at local sunrise (15:00 UTC). Click to animate! https://cimss.ssec.wisc.edu/satellite-blog/wp-content/uploads/sites/5/2025/06/GOES18_CIMSSNatColor_Winter2SummerSolstice2025_Sunrise.mp4

Webapps about the Seasons

Screen shot of the webapp where one can explore the effect of the angle of incidence on sun’s energy. (Click on the image to go to the webapp.)
Explore the changing seasons on Earth by relating the orbit, rotation and solar insolation with this webapp by T. Whittaker. (Click on the image to go to the webapp.)
Summer Solstice GOES-19 Full Disk “CIMSS Natural Color” on June 20, 2025 at local sunset (23:00 UTC).

These images were made using NOAA data with geo2grid software, from UW-Madison, SSEC. T. Whittaker is thanked for the web apps.

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