1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Visible images (above) and Infrared Window images (below) showed the slow organization of cloud features associated with Tropical Storm Lala southeast of Hawai’i on 13 August 2026. Overlays of GOES-18 GLM Flash Points indicated that lightning activity was sparse during that time period. Lala was moving through an environment of very low deep-layer wind shear and traversing fairly warm Sea Surface Temperatures — factors which favored further intensification as Lala approached Hawai’i.

During the preceding nighttime hours, before Potential Tropical Cyclone One-C had intensified to become Tropical Storm Lala, VIIRS Day/Night Band images from NOAA-20 and NOAA-21 (below) displayed the faint signature of cloud features — faint because the Moon had not yet risen at that location, so the only source of illumination was atmospheric airglow.

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Eyes around the world were turned toward Greenland, Iceland, and Spain as a total solar eclipse tracked across parts of the Northern Hemisphere yesterday, 12 August 2026. If you haven’t already seen the CIMSS Blog post on yesterday’s total solar eclipse from the GOES perspective, be sure to check it out. However, this was a high-latitude eclipse and it was difficult to see the lunar shadow from the standard geostationary view. By contrast, the polar-orbiting satellites of the Joint Polar Satellite System (JPSS) are able to view the eclipse from a much more direct angle. Here’s a static true color view from NOAA21’s VIIRS at 1720 UTC. Note the expected coloration over the eastern contiguous United States, but as you look further to the north you see the darkening of the ground due to increasingly obscured sunlight.

Even better, the JPSS satellites also feature the VIIRS imager. What better way to view the simultaneous day and night of a solar eclipse than the Day/Night Band? Let’s take a look! These images have been plotted via the excellent polar SLIDER resource from our colleagues and friends at the Cooperative Institute for Research in the Atmosphere. These images are North Pole views, with Alaska at the bottom center and Greenland off to the upper right. You can see much of the contiguous United States in the lower right.

The first hint of a partial eclipse began at 1534 UTC (7:34 AM Alaska time, for context). Therefore, this first image, at 1518 shows the pre-eclipse environment. SLIDER overlays previous swaths on the image, hence the nighttime lights in the United States. However, in general nothing too unusual appears to be going on.

The next swath is at 1603 UTC. The eclipse is only a few minutes old at this point, and there’s not really much that is easily identifiable as being an effect of the dimming sun. Still, we see lots of clouds over the North Pole and some clear seas between Greenland and Canada.

By the time we reach 1659 UTC, however, we see a substantial change in the darkness over eastern Siberia. The Day/Night band relies on moonlight when the sun is not available, and when the moon is not present the views are going to be dark. Geometrically, a solar eclipse can only take place during a new moon. Therefore the nighttime parts of the globe are going to be black, and the part of the Earth beneath the moon’s shadow will also be dark. This swath was right at the time the total eclipse first began.

With the next swath at 1744 UTC, we see that the shadow has moved to far northern Greenland. The eclipse reached it maximum at 1746 UTC, so this view represents the eclipse at effectively its greatest extent. We can see this as a dark hole in upper center-right of the next image, where previously Greenland clearly had snow, clouds, and ice.

The JPSS satellites are sun-synchronous, moving from east to west so that they feature largely similar solar characteristics from one swath to the next. Because of this, there are no further satellite views of the eclipse as it moved onward to Spain. Regardless, JPSS gave us a unique perspective of one of nature’s most thrilling (and predictable!) natural phenomena. Stay tuned to the CIMSS Satellite Blog on 2 August 2027, when we’ll be discussing the next solar eclipse which will be taking place over Spain, Africa, and the Mediterranean.

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10-minute Full Disk scan Near-Infrared “Vegetation” images from GOES-18/GOES-West (above) and GOES-19/GOES-East (below) revealed the shadow of a total solar eclipse on 12 August 2026 — which began by moving eastward across far northern Alaska and Arctic Canada, then curved southeast across Greenland, Iceland and far western Europe before fading from view with sunset over western Africa.

A closer view of GOES-19 images (below) showed the solar eclipse shadow as it passed across eastern Greenland and then Iceland.

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1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Visible images (above) and Infrared Window images (below) included time-matched plots of SPC Storm Reports — which showed thunderstorms that produced several tornadoes and wind gusts as high as 97 mph in Illinois, and hail as large as 3.00″ in diameter in Indiana. The high concentration of damaging winds in the northeast Illinois and northwest Indiana area was only a portion of a derecho event that spanned from eastern Iowa to eastern Kentucky (NWS Chicago | NWS Northern Indiana).

Thunderstorm overshooting tops exhibited infrared brightness temperatures as cold as -80 to -83 C, denoted by violet pixels (above). According to a plot of rawinsonde data from Quad Cities, Illinois (below), those infrared brightness temperatures represented a ~2 km overshoot of the Most Unstable (MU) air parcel’s Equilibrium Level (EL). For an early morning sounding, it showed a very moist and unstable air mass — and the Downdraft CAPE (DCAPE) value of 1194 J/kg highlighted the potential for strong downward transport of momentum to the surface, helping to produce the widespread wind damage that was observed.

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