Great Lakes ice motion and lake-effect snow bands

February 27th, 2014
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

A southward to southeastward surge of arctic air across the Great Lakes in the wake of a strong cold frontal passage (18 UTC surface analysis) on 27 February 2014 produced widespread lake-effect snow bands and also contributed to a renewed growth of ice. McIDAS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) showed (1) a variety of lake-effect cloud bands streaming across Lake Superior, Lake Michigan, Lake Huron, and western Lake Erie, (2) the motion of lake ice, due to strong northerly, northwesterly, and westerly winds across the region, and (3) the rapid formation of new lake ice in the previously ice-free nearshore waters in the far northwestern portion of Lake Superior.

A comparison of AWIPS images of Suomi NPP VIIRS 0.64 µm visible channel data and a false-color “snow/ice vs cloud discrimination” Red/Green/Blue (RGB) product at 19:02 UTC (below) demonstrated how the RGB product could be used to highlight the various cloud features — snow and ice appeared as darker shades of red, while supercooled water droplet clouds were depicted as varying shades of white (glaciated cloud features exhibited a pink to lighter red appearance).

Suomi NPP VIIRS 0.64 µm visible channel and false-color RGB images

Suomi NPP VIIRS 0.64 µm visible channel and false-color RGB images

Lake Michigan: ice motion, cloud streets, and a mesovortex

February 16th, 2014
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

AWIPS images of GOES-13 0.63 µm visible channel data (above; click image to play animation) displayed a number of interesting Lake Michigan features on 16 February 2014: (1) the motion of lake ice in the northern and far eastern portions of the lake, (2) the formation of parallel cloud streets over the ice-free waters of the central part of lake, and (3) the development of a mesoscale vortex (or “mesovortex”) over the southern end of the lake.

Northerly winds were blowing down the long axis of Lake Michigan in the wake of a departing area of low pressure; Metop ASCAT surface scatterometer wind speeds were as high as 35 knots at 15:26 UTC (below).

GOES-13 0.63 µm visible channel image with ASCAT surface scatterometer winds

GOES-13 0.63 µm visible channel image with ASCAT surface scatterometer winds

False-color Red/Green/Blue (RGB) images created from Suomi NPP VIIRS 0.64 µm visible and 1.61 µm “snow/ice channel” data (below) helped to disctiminate between snow cover and ice fearures (which appeared as varying shades of red) and supercooled water droplet cloud features (which appeared as brighter shades of white). Even in the relatively short 1.5 hour period separating the two VIIRS RGB images, a significant amount of ice motion could be seen.

Suomi NPP VIIRS false-color "snow/ice vs cloud discrimination" RGB images

Suomi NPP VIIRS false-color “snow/ice vs cloud discrimination” RGB images

As an aside, another feature of interest seen in the GOES-13 visible images included arc-shaped aircraft dissipation trails (or “distrails”), created by air traffic that was likely circling upon approach or departure from the Chicago O’Hare or Midway airports (below; click image to play animation). Partcles in the aircraft exhaust acted as ice condensation nuclei, glaciating a trail as they penetrated the supercooled water droplet cloud deck.

GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

“Industrial-enhanced” snow in Texas

February 10th, 2014

GOES-15 (left) and GOES-13 (right) 0.63 µm visible channel images [click to play animation]

GOES-15 (left) and GOES-13 (right) 0.63 µm visible channel images [click to play animation]

Examples of “industrial-enhanced snow” were seen in the Texas Panhandle region on 10 February 2014. In the overnight hours, areas downwind of agricultural plants near Borger (KBGD) received anywhere from 3.0 to 4.3 inches of snowfall. During the following morning and early afternoon hours, the particles contained within the hot, moist plume emanating from a factory located just northeast of Amarillo (KAMA) acted to glaciate the supercooled water droplets within the surrounding stratus deck — as the ice particles fell out of the cloud as snow, the cloud deck began to partially dissipate as seen in McIDAS images of 1-km resolution GOES-15 (GOES-West) and GOES-13 (GOES-East) 0.63 µm visible channel data (above; click image to play animation).

A similar comparison of 4-km resolution GOES-15 and GOES-13 3.9 µm shortwave IR images (below; click image to play animation) confirmed that the plume streaming southward from the Amarillo area was indeed glaciated — the plume appeared significantly colder (brighter white) compared to the surrounding supercooled water droplet stratus cloud deck, which appeared warmer (darker gray) due to the shortwave IR channel’s sensitivity to the reflection of solar radiation off the liquid droplet cloud tops.

GOES-15 (left) and GOES-13 (right) 3.9 µm shortwave IR channel images [click to play animation]

GOES-15 (left) and GOES-13 (right) 3.9 µm shortwave IR channel images [click to play animation]

A comparison of AWIPS images of 1-km resolution Terra MODIS 0.65 µm visible channel, 3.7 µm shortwave IR channel, and 11.0 µm IR window channel images (below) provided a slightly sharper view than the GOES images. Again, the glaciated plume south of Amarillo appeared colder (brighter white) than the surrounding supercooled water droplet clouds; on the IR window channel image, the slightly warmer (darker gray) signature was due to the satellite sensing radiation from the warmer ground surface through the thinner glaciated areas of the cloud plume.

Terra MODIS 0.65 µm visible, 3.7 µm shortwave IR, and 11.0 µm IR window channel images

Terra MODIS 0.65 µm visible, 3.7 µm shortwave IR, and 11.0 µm IR window channel images

A 250-meter resolution Terrra MODIS true-color Red/Green/Blue (RGB) image from the SSEC MODIS Today site (below; visualized using Google Earth) showed that the plume was drifting southward over parts of Interstate 27; one inch of snowfall was reported as far south as Happy, in the far northern part of Swisher county.

Terra MODIS true-color Red/Green/Blue (RGB) image

Terra MODIS true-color Red/Green/Blue (RGB) image

===== 11 February Update =====

On the folllowing day, a Terra MODIS true-color image at 17:44 UTC (below; visualized using Google Earth) provided a fantastic view of the mesoscale patch of snow cover southwest of Borger, Texas.

Terra MODIS true-color image (visualized using Google Earth)

Terra MODIS true-color image (visualized using Google Earth)

Lake ice, and “nuclear power plant effect” snow

February 6th, 2014
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

McIDAS images of GOES-13 0.6 µm visible channel data (above; click image to play animation) showed the motion of ice in the nearshore waters of Lake Michigan on 06 February 2014. Along the coast of Wisconsin, westerly winds — gusting as high as 27 knots at Manitowoc (KMTW), and 23 knots at Sheboygan (KSBM) — were causing the thin ice to continue drifting eastward during the day.

Another feature of interest seen on the GOES-13 visible imagery was a long, narrow cloud plume streaming southeastward in far northern Illinois — this cloud plume was a result of waste heat and moisture from the cooling towers at the Byron Nuclear Generating Station (located just east of the red “>” symbol on the images). Although there appeared to be no meteorological clouds over northern Illinois during the late morning and afternoon hours, light snow was reported at De Kalb from 16 – 19 UTC (animation of visible images, with surface reports). An AWIPS comparison of 1-km resolution MODIS 0.65 µm visible channel and 3.7 µm shortwave IR channel images at 17:15 UTC (below) indicated that the cloud plume from the Byron nuclear plant appeared to be drifting very near De Kalb (KDKB), which was likely causing the light snow (the surface visibility at De Kalb was reduced to 2.5 miles at 17 UTC). On the MODIS 3.7 µm shortwave IR image, the widespread supercooled water droplet clouds — as well as the nuclear power plant plume — appeared warmer (darker gray) than the surrounding snow-covered ground, due to this channel’s sensitivity to solar radiation reflected off the cloud top water droplets.

At least one other case of “nuclear power plant effect” snowfall has been documented, downwind of the Beaver Valley power plant in Pennsylvania.

MODIS 0.65 µm visible channel and 3.7 µm shortwave IR channel images

MODIS 0.65 µm visible channel and 3.7 µm shortwave IR channel images

Farther to the north, a significant amount of ice motion could also be seen in the western portion of Lake Superior (below; click image to play animation).

GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)