Signature of ice accrual across the Upper Midwest

April 4th, 2020 |

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly precipitation type plotted in red [click to play animation | MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) images, with hourly precipitation type plotted in red [click to play animation | MP4]

GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) showed a variety of precipitation types as a strong cold front moved slowly eastward across the Upper Midwest during the 02 April03 April 2020 period — including thundersnow snow at Aberdeen, South Dakota and Oakes, North Dakota (at 18 UTC on 02 April) and freezing rain at a few sites in northern Iowa, the eastern Dakotas and western Minnesota.

On the following day, in a comparison of GOES-16 “Red” Visible (0.64 µm) and Day Snow Fog Red-Green-Blue (RGB) images (below), the RGB images revealed darker red swaths across southeastern South Dakota, northwestern Iowa and western Minnesota (at the 1.61 µm wavelength, ice absorbs radiation more strongly than snow — which contributed to the darker appearance of those swaths). Note that these ice accrual swaths exhibited no signature in the Visible imagery.

GOES-16 "Red" Visible (0.64 µm) and Day Snow Fog RGB images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) and Day Snow Fog RGB images [click to play animation | MP4]

Props to Carl Jones (NWS Grand Forks) for pointing this feature out.

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