The Kanlaon Volcano in the Philippines erupted at 0703 UTC on 9th December 2024. JMA Himawari-9 Air Mass RGB images from 0650-1500 UTC (above) — created using Geo2Grid — showed the volcanic cloud as it drifted westward across the Sulu Sea. This volcanic cloud was primarily composed of SO2 (along with some ash), and exhibited shades of orange in the RGB images. The “Red” component of the Air Mass RGB uses the 7.3 µm spectral band, which is sensitive to SO2 absorption — for example, see this blog post.

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GOES-16 (GOES-East) Red Visible (0.64 µm) images (above) revealed the development of Horizontal Convective Roll (HCR) clouds — a signature often associated with blowing snow — across parts of North Dakota, South Dakota, Minnesota and Wisconsin on 4th December 2024. Strong northwesterly winds in the wake of an arctic cold front were gusting in excess of 40 knots at several locations (including a peak gust of 57 knots or 66 mph in northeastern North Dakota), with blowing snow restricting the surface visibility to near zero at times. Periods of localized blizzard conditions prompted the issuance of several Snow Squall Warnings, with some of those warnings covering portions of Interstates 29 and 94 in North Dakota and Minnesota. Note that the HCRs were highly concentrated within the lower elevations of the Red River Valley along the North Dakota / Minnesota border.

Blowing Snow RGB images from GOES-19 (Preliminary/Non-operational) — created using Geo2Grid — provided a more detailed view of the widespread HCR clouds (below). Existing snow cover appeared as darker shades of red in the RGB imagery, while bare ground appeared as brighter shades of green; supercooled water droplet clouds appeared as brighter shades of white.

VERY poor visibility inside horizontal convective roll snow bands near Grand Forks, North Dakota, this afternoon. Visibility at times ~100yds.

Just W GF @NWSGrandForks #NDwx pic.twitter.com/uLaYAdMIF4

— Kyle J Gillett (@wxkylegillett) December 4, 2024

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Cuba’s largest power plant went offline around 0700 UTC on 4th December 2024 (media report), which led to a collapse of the power grid across much of the island. A toggle between VIIRS Day/Night Band images from Suomi-NPP and NOAA-20 (above) provided a before/after view of nighttime city light emissions across Cuba — there was a notable decrease in city lights evident in the later NOAA-20 (mislabeled as NPP) Day/Night Band image.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) Clean Infrared Window (10.3 µm) images (above) showed a lake effect snow (LES) band that intensified over far eastern Lake Erie, shortly before moving inland across western New York after sunset on 30th November 2024. Intermittent lightning activity was seen immediately inland as the LES band moved across Interstate 90 between Buffalo (KBUF) and Dunkirk (KDKK), with several GLM Flash Points appearing.

A similar animation of GOES-16 Infrared images included overlays of both GLM Flash Extent Density and Flash Points (below). Note the slight northward displacement of the Flash Extent Density pixels compared to the Flash Points — this is because commonly-used Gridded GLM products (such as Flash Extent Density, Minimum Flash Area and Total Optical Energy) are not corrected for parallax, as the GLM Flash Points are.

A stepped sequence of 6 times with GLM observations (2329 UTC/2339 UTC/2345 UTC/0005 UTC/0008 UTC/0051 UTC) is shown below, to provide an easier examination of the displacement between GLM Flash Extent Density and GLM Flash Points. Much of this satellite-detected lightning activity was occurring near Lackawanna (south of Buffalo), where thundersnow was observed.

Constant thundersnow in Lackawanna!! pic.twitter.com/t9K7uzQ2ru

— BuffaloWeather (@weather_buffalo) December 1, 2024

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