This website works best with a newer web browser such as Chrome, Firefox, Safari or Microsoft Edge. Internet Explorer is not supported by this website.

CIMSS Satellite Blog

MENU

Standing wave cloud over the north shoreline of Saginaw Bay

By Scott Bachmeier •

5-minute CONUS Sector GOES-19 (GOES-East) imagery (above) revealed the brief development of what appeared to be a standing wave cloud — caused by a vertically-propagating gravity wave — that was anchored near the north coast of Saginaw Bay, Michigan on 20 April 2026. At first glance, this author was reminded of similar-appearing standing... Read More

5-minute GOES-19 Visible images (top left), Infrared images (top right), Mid-level Water Vapor images (bottom left) and Upper-level Water Vapor images (bottom right), from 1951 UTC on 20 April to 0001 UTC on 21 April; hourly surface wind barbs are plotted in white [click to play MP4 animation]

5-minute CONUS Sector GOES-19 (GOES-East) imagery (above) revealed the brief development of what appeared to be a standing wave cloud — caused by a vertically-propagating gravity wave — that was anchored near the north coast of Saginaw Bay, Michigan on 20 April 2026. At first glance, this author was reminded of similar-appearing standing wave clouds that form along the Minnesota coast of Lake Superior.

A toggle between GOES-19 images and Topography (below) seemed to show that the northwestern edge of the cloud feature lined up with the final (subtle) drop in topography near the coast — however, since there was not the strong NW offshore surface wind flow common to the aforementioned Minnesota example, perhaps the onshore (and slightly upslope) lake breeze played a role in vertical gravity wave initiation? Until a sound explanation rooted in science is stumbled upon, this event will fall into the coveted “What the heck is this?” blog post category.

GOES-19 Visible/Infrared/Water Vapor images at 2136 UTC on 20 April, compared with Topography; Surface Wind barbs are plotted in white [click to enlarge]

View only this post Read Less

Lake effect cloud plume produces light snow downwind of the Great Salt Lake

By Scott Bachmeier •

5-minute CONUS Sector GOES-18 (GOES-West) and GOES-19 (GOES-East) Nighttime Microphysics RGB + daytime True Color RGB images from the CSPP GeoSphere site (above) showed a lake effect cloud plume that developed over the southern half of Great Salt Lake on 17 April 2026 — which produced a swath of light snowfall downwind (southeast) of the lake... Read More

5-minute GOES-18 (left) and GOES-19 (right) Nighttime Microphysics RGB + daytime True Color RGB images, from 0401-1556 UTC on 17 April [click to play MP4 animation]

5-minute CONUS Sector GOES-18 (GOES-West) and GOES-19 (GOES-East) Nighttime Microphysics RGB + daytime True Color RGB images from the CSPP GeoSphere site (above) showed a lake effect cloud plume that developed over the southern half of Great Salt Lake on 17 April 2026 — which produced a swath of light snowfall downwind (southeast) of the lake that was apparent in True Color RGB images after sunrise.

Day Snow-Fog RGB images from GOES-18 and GOES-19 created using Geo2Grid (below) were helpful in discriminating between the lake effect clouds (shades of white) and the fresh snow cover (shades of red) immediately downwind of the Great Salt Lake after sunrise. Bare ground appeared as shades of green.

5-minute Day Snow-Fog RGB images from GOES-18 (left) and GOES-19 (right), from 1331-1801 UTC on 17 April [click to play MP4 animation]

A plot of the 24-hour total observed snowfall (below) indicated that amounts were generally 1 inch or less at lower-elevation sites downwind of the Great Salt Lake (with 2 sites near topographical features reporting 3.0 inches).

Plot of 24-hour total observed snowfall ending at 1200 UTC on 17 April [click to enlarge]

Plot of 24-hour total observed snowfall ending at 1200 UTC on 17 April [click to enlarge]

GOES-18 Infrared images (below) depicted cloud-top infrared brightness temperatures within the lake effect cloud plume that were as cold as -35ºC. Note that Salt Lake City International Airport (KSLC) was reporting light snow which reduced the surface visibility to 8 miles at 0454 UTC, as the lake effect cloud was moving over that location.

5-minute GOES-18 Infrared images, from 0401-1201 UTC on 17 April [click to play MP4 animation]

5-minute GOES-18 Infrared images, from 0401-1201 UTC on 17 April [click to play MP4 animation]

According to a plot of 0000 UTC rawinsonde data from Salt Lake City (below), an air temperature of -35ºC occurred at an elevation of 5900 m (19358 ft). Since the water temperature of the lake was around 50ºF or 10ºC that day, the surface temperature of the sounding was modified to match that value.

Plot of rawinsonde data from Salt Lake City at 0000 UTC on 17 April [click to enlarge]

Surface-temperature-modified plot of rawinsonde data from Salt Lake City at 0000 UTC on 17 April [click to enlarge]

View only this post Read Less

Lightning-related fatality in Wisconsin

By Scott Bachmeier •

1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Infrared images (above) included plots of 1-minute GLM Flash Points (which are parallax-corrected to correspond to their surface locations) — and showed an increase in thunderstorm coverage and lightning activity across southeastern Wisconsin late in the day on 15 April 2026.Unfortunately, one lightning-related fatality occurred south of... Read More

1-minute GOES-19 Infrared images, with plots of GLM Flash Points (white dots), from 2301 UTC on 15 April to 0100 UTC on 16 April [click to play MP4 animation]

1-minute GOES-19 Infrared (10.3 µm) images with plots of GLM Flash Points (white dots) and METAR surface reports (cyan), from 2301 UTC on 15 April to 0100 UTC on 16 April [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Infrared images (above) included plots of 1-minute GLM Flash Points (which are parallax-corrected to correspond to their surface locations) — and showed an increase in thunderstorm coverage and lightning activity across southeastern Wisconsin late in the day on 15 April 2026.

Unfortunately, one lightning-related fatality occurred south of Pewaukee, Wisconsin around 0043 UTC or 7:43 PM Central Time (Local Storm Report). A cursor sample of a GLM Flash Point just southeast of Pewaukee (below) revealed a rather large flash area of 1114 km2 at 0041 UTC (7:41 PM Central Time).

GOES-19 Infrared image at 0041 UTC on 16 April, with a cursor sample of a GLM Flash Point near Pewaukee, Wisconsin [click to enlarge]

GOES-19 Infrared (10.3 µm) image at 0041 UTC on 16 April, with a cursor sample of a GLM Flash Point (white dot) near Pewaukee, Wisconsin [click to enlarge]

1-minute GOES-19 Infrared images with contours of ProbSevere LightningCast probability (below) indicated that the LightningCast probability over Pewaukee was consistently at or above 90% beginning at 0015 UTC.

1-minute GOES-19 Infrared images, with an overlay of LightningCast probability contours, from 2340 UTC on 15 April to 0100 UTC on 16 April [click to play MP4 animation]

1-minute GOES-19 Infrared (10.3 µm) images, with an overlay of LightningCast probability contours, from 2340 UTC on 15 April to 0100 UTC on 16 April [click to play MP4 animation]

A plot of LightningCast Probability and GOES-19 GLM Flash Count (below) revealed that the LightningCast Probability was 73% or higher during the 30-minute period preceding a marked increase in GLM Flash Count in the vicinity of Waukesha County Airport (KUES, which is located about 3 miles south of Pewaukee).

Plot of LightningCast Probability and GOES-19 GLM Flash Count in the vicinity of Waukesha Airport (KUES) [click to enlarge]

Plot of LightningCast Probability and GOES-19 GLM Flash Count in the vicinity of Waukesha Airport (KUES) [click to enlarge]

This is the first lightning fatality of 2026. Details are scarce right now.The safest place to be during a thunderstorm is in a substantial building with electrical and plumbing in the walls. Fully enclosed metal vehicles also provide protection.When thunder roars, go indoors!

— National Lightning Safety Council (@lightningsafety.bsky.social) 2026-04-16T13:25:15.423Z

View only this post Read Less

Severe thunderstorms produce tornadoes, large hail and damaging winds across southern Wisconsin

By Scott Bachmeier •

1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Visible images (above) included time-matched (+/- 3 minutes) plots of SPC Storm Reports — which showed the tornadoes, large hail (up to 4.00″ in diameter) and damaging winds (as high as 88 mph) that occurred across much of southern Wisconsin (along with adjacent parts of far northeast Iowa and far... Read More

1-minute GOES-19 Visible (0.64 µm) images with time-matched (+/- 3 minutes) plots of SPC Storm Reports, from 2030 UTC on 14 April to 0015 UTC on 15 April [click to play animated GIF | MP4]

1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Visible images (above) included time-matched (+/- 3 minutes) plots of SPC Storm Reports — which showed the tornadoes, large hail (up to 4.00″ in diameter) and damaging winds (as high as 88 mph) that occurred across much of southern Wisconsin (along with adjacent parts of far northeast Iowa and far southeast Minnesota) on 14 April 2026. Numerous overshooting tops were seen in the Visible images.

The corresponding 1-minute GOES-19 Infrared images (below) revealed pronounced enhanced-V cloud-top signatures with several of the severe thunderstorms.

1-minute GOES-19 Infrared (10.3 µm) images with time-matched (+/- 3 minutes) plots of SPC Storm Reports, from 2030 UTC on 14 April to 0031 UTC on 15 April [click to play animated GIF | MP4]

The coldest cloud-top infrared brightness temperatures exhibited by pulses of overshooting tops were -78ºC (brighter white pixels embedded within dark black areas) — which corresponded to a significant (~2 km) overshoot of the Most Unstable (MU) air parcel’s Equilibrium Level (EL), according to plots of rawinsonde data from Davenport, Iowa (below). CAPE values of 4000-4300 J/kg indicated that significant instability was present south of a frontal boundary which was draped across Iowa, Wisconsin and lower Michigan.

Plots of rawinsonde data from Davenport, Iowa at 1800 UTC and 2100 UTC on 14 April [click to enlarge]

Plots of rawinsonde data from Davenport, Iowa at 1800 UTC and 2100 UTC on 14 April [click to enlarge]

View only this post Read Less

  • last_page First
  • Last last_page

Search blog