1-minute Mesoscale Domain Sector GOES-19 (GOES-East) True Color RGB images from the CSPP GeoSphere site (above) highlighted notable smoke plumes from two large wildfires in southeast Georgia (the Pineland Road Fire near the Florida border, and the Brantley Highway 82 Fire farther to the northeast), in addition to another wildfire in northern Florida on 21 April 2026. Those particular wildfires were burning in parts of Georgia and Florida that were experiencing Exceptional Drought conditions.

1-minute GOES-19 GeoColor RGB images with an overlay of Next Generation Fire System (NGFS) Fire Detection polygons (below) provided a close-up view of the smoke plume and thermal signature associated with the Brantley Highway 82 wildfire in southeast Georgia — which was nearly under control at 700 acres in size during the early morning hours on 21 April, but then quickly grew out of control as surface winds abruptly shifted to the northeast then to the east (occasionally gusting to 22-23 mph), with the fast-moving wildfire burning an area of 5000 acres by the end of the day. Numerous evacuation orders were issued, about 87 homes were destroyed and schools throughout Brantley County were closed due to air quality concerns.

At 1758 UTC, the wildfire first exhibited a 3.9 µm shortwave infrared brightness temperature of 138ºC (below) — which is the saturation temperature of GOES-19 ABI Band 7 detectors. Also of note, at that time the Fire Radiative Power of the thermal signature was a rather high 6594 MW.

Periodic bursts of brighter-white pyrocumulus clouds rose above the hazy gray smoke plume, such as was seen just west of the fire’s thermal anomaly at 2019 UTC (below).

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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.

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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.

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).

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.

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.

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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).

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.

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).

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

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