The Great Lakes, viewed using GOES-16 and NOAA-20 imagery

January 21st, 2022 |

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

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) displayed mesovortices over southern Lake Michigan on 21 January 2022. The formation of these mesovortex features was aided by a mid-lake convergence of surface winds, which was suggested by RAP40 surface wind fields and shown n more detail by Metop-C ASCAT winds from this site (below).

Metop-C ASCAT surface scatterometer winds [click to enlarge]

Farther to the north, in spite of a cold night across northeast Wisconsin and Upper Michigan — with morning low temperatures of -30ºF at Laona, Wisconsin and -39ºF at Amasa, Michigan — GOES-16 Visible images (below) showed that southerly winds helped to open an ice lead near the center of Green Bay, with a slow northward drift of pack ice in the northern half of the bay. A lone ice floe was also seen moving northward near the western edge of the clouds in Lake Michigan.

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

A toggle between NOAA-20 VIIRS True Color and False Color RGB images (below) revealed a more detailed view of the ice structure — and also showed the narrow southwest-to-northeast oriented damage path that remained from a June 2007 EF-3 tornado that went through a portion of Menominee, Langlade and Oconto counties. The higher spatial resolution of the VIIRS imagery helped to highlight the aforementioned isolated ice floe in Lake Michigan (which appeared as cyan in the False Color RGB image).

NOAA-20 VIIRS True Color and False Color RGB images [click to enlarge]

To the east, mesovortices were also observed in Lake Huron – long with ice floes drifting away from the coast of Lower Michigan (below).

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

A was the case in Lake Michigan, these Lake Huron mesovortices were forming along an axis of surface wind convergence, seen in Metop-B ASCAT data (below).

Metop-B ASCAT surface scatterometer winds [click to enlarge]

A larger-scale toggle between NOAA-20 VIIRS True Color and False Color RGB images — created using data received from the SSEC/CIMSS Direct Broadcast ground station — provided a view of the entire Great Lakes region (below). 

NOAA-20 VIIRS True Color RGB and False Color RGB images (credit: Margaret Mooney, CIMSS) [click to play animation]

Standing wave clouds over northeastern Minnesota

January 19th, 2022 |

GOES-16 Mid-level Water Vapor (6.9 µm) images [click to play animated GIF | MP4]

GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) revealed the formation of a standing wave cloud along the Minnesota shoreline of Lake Superior on 19 January 2022. This cloud feature was formed by a vertically-propagating internal gravity wave that resulted from the interaction of strong post-cold-frontal northwesterly winds with the topography of the shoreline — the terrain quickly drops from an elevation of about 2000 feet above sea level (over northeastern Minnesota) to about 600 feet above sea level (over Lake Superior) in a very short distance.

In a toggle between GOES-16 Water Vapor and Suomi-NPP VIIRS Infrared Window images at 1811 UTC (below), the coldest cloud-top infrared brightness temperatures were around -40ºC (lime green enhancement).

GOES-16 Mid-level Water Vapor (6.9 µm) and Suomi-NPP VIIRS Infrared Window (11.45 µm) images at 1811 UTC [click to enlarge]

A northwest-to-southeast oriented cross section of RAP40 model fields along line segment F-F’ (below) showed a deep pocket of positive Omega (upward vertical motion, yellow to red colors) that corresponded to the cloud band along Minnesota’s Lake Superior shoreline. Note that this Omega feature was vertically tilted in an “upshear” direction (toward the northwest), and extended upward to the 500 hPa pressure level. The depth and magnitude of this positive Omega decreased with time, leading to the dissipation of the standing wave cloud.

RAP40 model cross sections along Line F-F’ [click to play animated GIF | MP4]

Blowing snow in North Dakota and Minnesota

January 18th, 2022 |

GOES-16 Day Snow-Fog RGB images, with surface reports plotted in yellow [click to play animated GIF | MP4]

GOES-16 (GOES-East) Day Snow-Fog RGB images (above) displayed widespread streamers of blowing snow (pale shades of white) across much of North Dakota and far northwestern Minnesota on 18 January 2022. Blowing snow was lofted from the surface by elongated horizontal convective rolls that developed in the wake of a strong cold frontal passage — surface winds gusted to 58 knots (67 mph) at Garrison in western North Dakota, and the surface visibility was reduced to zero at several locations. An arctic air mass behind the cold front helped the surface temperature drop to -22º F at Willow City, ND the following morning.

A more uncluttered view — without plots of surface reports — is shown below (Interstates and major highways are plotted in gray). Some secondary highways were closed due to the ground blizzard conditions.

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

Explosive eruption of the Hunga Tonga volcano

January 15th, 2022 |

JMA Himawari-8 True Color RGB images [click to play animated GIF | MP4]

JMA Himawari-8 True Color RGB images created using Geo2Grid (above) showed the rapid expansion of a volcanic cloud following an explosive eruption of Hunga Tonga on 15 January 2022. An abrupt shock wave was also evident, which propagated radially outward in all directions.

The volcanic cloud also exhibited a striking appearance in GOES-17 (GOES-West) “Clean” Infrared Window (10.35 µm) images (below), with a pronounced arc of cloud-top gravity waves along its eastern edge as the bulk of the cloud material drifted westward. Pulsing concentric shock waves were also seen in the infrared imagery.

GOES-17 “Clean” Infrared Window (10.35 µm) images (credit: Tim Schmit, NOAA/NESDIS/ASPB) [click to play animated GIF | MP4]

The explosive nature of the eruption could be seen by examining 10-minute GOES-17 Visible and Infrared images  during the first 30 minutes (below) — only 20 minutes after the 0400 UTC eruption onset, the infrared cloud-top brightness temperature had already cooled to -100ºC (placing it in the lower stratosphere).     

GOES-17 “Red” Visible (0.64 µm, left) and “Clean” Infrared Window (10.35 µm, right) images [click to play animated GIF | MP4]

Beginning at 0705 UTC, a GOES-17 Mesoscale Domain Sector was positioned over the region, providing imagery at 1-minute intervals — Infrared images during the period 0705-1200 UTC are shown below. The crescent-shaped area of “bow shock wave” ripples persisted, due to the robust and dense volcanic cloud acting as an obstacle to the easterly winds within the stratosphere.  The 1-minute imaging was also able to capture the brief pulse of an overshooting top which exhibited an infrared brightness temperature of -105.18ºC at 0841 UTC (zoomed-in animation: GIF | MP4) — which could be a record cold cloud-top temperature, as sensed from a geostationary satellite (see this blog post).  

GOES-17 “Clean” Infrared Window (10.35 µm) images [click to play animated GIF | MP4]

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi-NPP, viewed using RealEarth (below), also showed the region of cloud-top gravity waves (with minimal parallax compared to GOES-17) .  

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi-NPP [click to enlarge]


Plot of 00 UTC rawinsonde data from Nandi, Fuji [click to enlarge]

Satellite-based lidar and limb sounder data indicated that the volcanic cloud reached maximum altitudes around 30-32 km — well into the lower stratosphere, where easterly winds existed according to 00 UTC rawinsonde data from Nandi, Fiji (above). The westward drift of most of the volcanic cloud as seen in a Suomi-NPP VIIRS Day/Night Band (0.7 µm) image (below) lined up well with wind barbs at 30 hPa (an altitude of 23.78 km on the Nandi NFFN sounding). 

Suomi-NPP VIIRS Day/Night Band (0.7 µm) image, with 30 hPa wind barbs plotted in violet and rawinsonde sites plotted in yellow [click to enlarge]


GOES-17 Mid-level Water Vapor (6.9 µm) Time Difference images (credit: Tim Schmit, NOAA/NESDIS/ASPB) [click to play animated GIF | MP4]

Propagation of the volcanic shock wave across the Pacific Ocean could be followed in GOES-17 (GOES-West) Mid-level Water Vapor (6.9 µm) Time Difference images (above). As the shock wave continued to propagate farther eastward across North/South America and then the Atlantic Ocean, the wave front could be seen in GOES-16 (GOES-East) Water Vapor Time Difference images (below). As the shock wave moved across southern Wisconsin, a brief rise/fall couplet in surface air pressure just prior to 1500 UTC (9:00 am CDT) was evident in plots from the University of Wisconsin – Madison’s Atmospheric, Oceanic and Space Sciences building rooftop tower (as well as the personal weather station of the author of this blog post).

GOES-16 Mid-level Water Vapor (6.9 µm) Time Difference images (credit: Tim Schmit, NOAA/NESDIS/ASPB) [click to play animated GIF | MP4]


GOES-17 and Himawari-8 visible imagery can be combined to create stereoscopic imagery of the eruption, as shown below.

GOES-17 Visible (Band 2, 0.64 µm) imagery, left, and Himawari-8 Visible (Band 3, 0.64 µm) imagery, right, 0400-0500 on 15 January 2022 (Click to enlarge)