GOES-17 “Red” Visible (0.64 µm) images, with and without plots of Derived Motion Winds [click to play animated GIF | MP4]

GOES-17 (GOES-West) “Red” Visible (0.64 µm) images, with and without plots of Visible Derived Motion Winds (above) showed a lower-tropospheric vortex propagating west-northwestward to the north of Hawai’i on 02 December 2021. There were no ship or buoy reports in the vicinity of the vortex, but Derived Motion Wind speeds were 20-25 knots or less during this time period.

Convergence near the center of the vortex was aiding in the development of some shallow convection — and GOES-17 Day Cloud Phase Distinction RGB images (below) indicated that the tops of many cloud features comprising the vortex were glaciating (exhibiting shades of green to yellow),

GOES-17 Day Cloud Phase Distinction RGB images [click to play animated GIF | MP4]

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MODIS-derived (from Terra and Aqua satellites) Bidirectional Reflectance Distribution Function (BRDF), above, (as noted in this blog post), shows the (meager) snow distribution as of early December. How many counties (or parishes) in the United States (out of more than 3000!) are clearly delineated in Satellite Imagery such as what is shown above? Counties that are primarily islands (or peninsulas) — Dare County in North Carolina, for example — show up well (False Color image shown here, in an image taken from VIIRS Today), but the inland borders do not.

For a county to be recognizable from Space, its landcover must differ significantly from adjacent counties. In the zooming-in animation below (from RealEarth, click the image to zoom in), users will note that Menominee County in northeast Wisconsin becomes apparent. Menominee County is almost entirely forest (unlike its neighbors) and as such has a much different signal in the (for example) 0.87 µm channel on VIIRS (or 0.86 µm on GOES-16). When it is zoomed in, the outlines of the County are obvious.

The county also shows up well in the VIIRS True Color/False Color toggle below, from 30 November. The southern edge of the snow at that time was just southeast of Menominee County, and the land-use change across the county border is apparent. Snow in the county (cyan in the False Color enhancement) is difficult to view from the imagery — because of the pine forests!

Menominee County has been on this blog before! In 2007, a tornado tracked through Menominee County and left a visible scar in satellite imagery (link). Eight years later (link), the scar was still apparent! November 6 2021 was a clear day over the upper Midwest. Suomi-NPP True Color imagery, below (link to original large image), still shows vestiges of the scar!

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NOAA-20 True Color RGB and Infrared Window (11.45 µm) images [click to enlarge]

NOAA-20 True Color RGB and Infrared Window (11.45 µm) images viewed using RealEarth (above) showed a large convective burst south of the center of Tropical Storm Nahtoh — located in the Philippine Sea — at 0356 UTC on 01 December 2021. A robust overshooting top near the center of the convective burst exhibited a cluster of cloud-top infrared brightness temperatures of -100ºC and colder (red pixels embedded within purple-to-yellow-to-black enhancement).

2.5-minute rapid scan JMA Himawari-8 Infrared Window (10.4 µm) images (below) displayed the evolution of Nyatoh as it transitioned from a Tropical Storm to a Category 1 Typhoon at 1200 UTC. The coldest cloud-top infrared brightness temperatures of convective overshooting tops were in the -90 to -98ºC range, but did not quite reach the -100ºC threshold that was seen in the VIIRS imagery.

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

Himawari-8 Infrared images with contours of 18 UTC deep-layer wind shear from the CIMSS Tropical Cyclones site (below) showed that Nyatoh was moving through an environment of low to moderate shear.

Himawari-8 Infrared images, with contours of 18 UTC deep-layer wind shear [click to enlarge]

Himawari-8 Infrared – Water Vapor Difference images (below) indicated that much of the deep convection associated with Typhoon Nyatoh was likely penetrating the local tropopause. This product is discussed here.

Himawari-8 Infrared – Water Vapor Difference images [click to enlarge]

DMSP SSMIS Microwave (85 GHz) images at 1905 UTC and 2148 UTC are shown below. A completely closed eyewall had not yet formed at those times.

DMSP-18 SSMIS Microwave (85 GHz) image at 1905 UTC [click to enlarge]

DMSP-17 SSMIS Microwave (85 GHz) image at 2148 UTC [click to enlarge]

===== 02 December Update =====

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

Typhoon Nyatoh rapidly intensified to a Category 3 storm by 1200 UTC, and then Category 4 by 1800 on 02 December (ADT | SATCON) — 2.5-minute rapid scan Himawari-8 Infrared images (above) showed the storm during this intensification period. During the 1200-1800 UTC time frame, subtle waves could be seen propagating south-southwestward across the cold central dense overcast, away from the center of Nyatoh. Energy from those waves was apparently propagating vertically, such that mesospheric airglow waves (reference) were evident in a Suomi-NPP VIIRS Day/Night Band (0.7 µm) image around 1650 UTC (below). Other examples of mesospheric airglow waves — caused by tropical cyclones, deep convection or jet streams — are available here .

Suomi-NPP VIIRS Day/Night Band (0.7 µm) image at 1650 UTC [click to enlarge]

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RealEarth has added GOES-17 IFR Probability Fields to its product suite (GOES-16 IFR Probability fields have been available in RealEarth for some time). They can be accessed most simply by entering ‘IFR Probabilty’ in the RealEarth search box. At present only the ‘PACUS’ domain (the GOES-17 equivalent of the GOES-16 ‘CONUS’ domain) is available, at 5-minute time-steps. An example over western Washington and offshore waters is shown above.

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