CIMSS Satellite Blog, CIMSS

Ice formation in southern Lake Michigan

By Scott Bachmeier • 7 February 2021

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) revealed an increasing amount of ice coverage within the nearshore waters of southern Lake Michigan on 07 February 2021 — this was due to a recent influx of arctic air across the Upper Midwest and western Great Lakes.A sequence of VIIRS True Color RGB and... Read More

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

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) revealed an increasing amount of ice coverage within the nearshore waters of southern Lake Michigan on 07 February 2021 — this was due to a recent influx of arctic air across the Upper Midwest and western Great Lakes.

A sequence of VIIRS True Color RGB and False Color RGB images from Suomi-NPP and NOAA-20 (below) provided 375-meter resolution views of the lake ice.

VIIRS True Color RGB and False Color RGB images [click to enlarge]

The MIRS Sea Ice Concentration product derived from Suomi-NPP ATMS data (below) depicted maximum values of 60-63% (lighter green), which was fairly consistent with the Ice Concentration analysis from GLERL.

MIRS Sea Ice Concentration product derived from Suomi-NPP ATMS data [click to enlarge]

The Suomi-NPP VIIRS Sea Surface Temperature product (below) revealed values of 34-39ºF along the leading edge of widespread lake effect cloud bands that were producing snowfall in Lower Michigan.

Suomi-NPP VIIRS Sa Surface Temperature product [click to enlarge]

Suomi-NPP VIIRS Sea Surface Temperature product [click to enlarge]

A 250-meter resolution Aqua MODIS True Color RGB image of the ice at 1917 UTC (from the MODIS Today site) is shown below.

Aqua MODIS True Color RGB image [click to enlarge]

Finally, an overpass of Landsat-8 offered a 30-meter resolution view of a portion of the lake ice near Chicago, as visualized using RealEarth (below).

Landsat-8 False Color RGB image [click to enlarge]

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Blowing snow across the Upper Midwest

By Scott Bachmeier • 6 February 2021

GOES-16 (GOES-East) Day Snow-Fog RGB images (above) showed widespread horizontal convective rolls (HCRs) which highlighted areas where blowing snow was more concentrated across parts of southern Manitoba and the Upper Midwest on 06 February 2021. Snow cover (and glaciated clouds) appeared as shades of red, with bare ground exhibiting lighter shades of green and... Read More

GOES-16 Day Snow-Fog RGB images [click to play animation | MP4]

GOES-16 (GOES-East) Day Snow-Fog RGB images (above) showed widespread horizontal convective rolls (HCRs) which highlighted areas where blowing snow was more concentrated across parts of southern Manitoba and the Upper Midwest on 06 February 2021. Snow cover (and glaciated clouds) appeared as shades of red, with bare ground exhibiting lighter shades of green and low-level water droplet clouds appearing as brighter shades of white.

Closer views of the northern, central and southern portions of the region where blowing snow was most prevalent are shown below. The HCRs were evident during the early to late morning hours across southern Manitoba, far eastern North Dakota and northwestern Minnesota — and then became more apparent across western/southern Minnesota extending into far northern Iowa as the day progressed. Surface reports showed that the visibility fluctuated dramatically at some sites as HCRs moved through.

GOES-16 Day Snow-Fog RGB images [click to play animation | MP4]

Terra MODIS True Color and False Color RGB images [click to enlarge]

In comparisons of MODIS True Color and False Color RGB images from Terra (above) and Aqua (below), the areal coverage of HCRs could be seen in the False Color imagery.

Aqua MODIS True Color and False Color RGB images [click to enlarge]

Farthest to the north, one cluster of HCRs appeared to originate over Lake Manitoba — as seen in 30-meter resolution Landsat-8 False Color imagery from RealEarth (below).

Lansdsat-8 False Color RGB image [click to enlarge]

Two notable pilot reports across southern Minnesota (below) showed that flight visibility was restricted to 4 miles at an elevation of 3000 feet, and the tops of HCRs extended to 5000 feet.

GOES-16 Day Snow-Fog RGB images, with plots of Pilot Reports [click to enlarge]

Additional material on satellite identification of blowing snow is available here and here.

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South Atlantic cyclone off the coast of Uruguay

By Scott Bachmeier • 5 February 2021

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed a cyclone (surface analyses) moving off the coast of Uruguay on 05 February 2021. What appeared to be an eye-like feature developed at the storm center toward the end of the day.A toggle between VIIRS True Color RGB images from Suomi NPP and... Read More

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

GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed a cyclone (surface analyses) moving off the coast of Uruguay on 05 February 2021. What appeared to be an eye-like feature developed at the storm center toward the end of the day.

A toggle between VIIRS True Color RGB images from Suomi NPP and NOAA-20 as viewed using RealEarth (below) provided a larger scale perspective of the cyclone.

VIIRS True Color RGB images from Suomi NPP and NOAA-20 [click to enlarge]

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Cold temperatures across the North Slope of Alaska

By Scott Bachmeier • 4 February 2021

Suomi NPP VIIRS Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) images (above) revealed a large area of cold surface infrared brightness temperatures across much of the North Slope of Alaska on 04 February 2021 — with the coldest IR temperature being -56ºC (darker shades of violet) about 30 miles south-southeast of Umiat (PAUM) on the 1221 UTC image. The surface air temperature at the nearby Umiat RAWS site around that time was -55ºF (-48.3ºC). Narrow fingers of cold air drainage into some of the river valleys along the northern slopes of the Brooks Range (topography) were also apparent.

The corresponding GOES-17 “Clean” Infrared Window (10.35 µm) images (below) also showed the large area of cold surface IR brightness temperatures, but the temperatures were not as cold (in the -40 to -50ºC range), and the small-scale signatures of various topographical features were not depicted.