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 wind gusts as high as 98 mph, hail as large as 3.75 inches in diameter and isolated tornadoes across parts of Montana, Wyoming, North Dakota and South Dakota from the late afternoon until a few hours after after sunset on 07 June 2026. Widespread overshooting tops were very apparent in the Visible imagery — and initial discrete storms exhibited enhanced-V signatures in the Infrared imagery, before upscale growth resulted in a large Mesoscale Convective System centered over western North Dakota.

Plots of rawinsonde data in the pre-convective environment at Bismarck ND (KBIS) and Rapid City SD (KUNR) are shown below. Of particular significance were the large Downdraft CAPE (DCAPE) values of 1730 J/kg at 0000 UTC and 1569 J/kg at 1800 UTC at Rapid City and Bismarck, respectively — which highlighted the potential for a strong downward transport of air to surface, producing the widespread damaging winds that were seen across the region.

The coldest cloud-top infrared brightness temperatures in the 1-minute GOES-19 Infrared Window images were around -70C — which represented a significant overshoot of the Most Unstable (MU) air parcel’s Equilibrium Level (EL) as depicted in the plots of rawinsonde data.

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1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Visible images (above) and Infrared Window images (below) showed the development of supercell thunderstorms in parts of southern Saskatchewan and southern Manitoba on 06 June 2026. GOES-19 GLM Flash Points highlighted the abundant lightning activity that was associated with these thunderstorms. The supercell thunderstorms developed in the vicinity of a cold frontal boundary — and produced hail as large as 2″ in diameter, and also prompted the issuance of tornado warnings in both Manitoba and Saskatchewan.

A toggle between GOES-19 Visible and Infrared Window images at 2145 UTC (below) included a cursor sample of the coldest cloud-top infrared brightness temperature of the Manitoba thunderstorm, wich was -68.18C.

A toggle between GOES-19 Visible and Infrared Window images at 2335 UTC (below) included a cursor sample of the coldest cloud-top infrared brightness temperature for the Saskatchewan thunderstorm, which was -68.67C.

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A moderate intensity solar flare was detected by the SUVI on GOES-18 (GOES-West), which peaked at 0136 UTC on 03 June 2026 (above). These SUVI images were sourced from the SSEC Geostationary Satellite Imagery site.

The Space Weather Prediction Center classified this solar flare as M9.3 intensity (below).

Later on 03 June, a second solar flare was evident in GOES-19 (GOES-East) SUVI (below).

Finally, a few hours later on 03 June a third solar flare directed a Coronal Mass Ejection (CME) off the northeastern limb of the Sun, as viewed by the GOES-19 SUVI (below).

As a result of these three CMEs, a G3 Geomagnetic Storm Watch was issued (below).

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5-minute CONUS Sector GOES-18 (GOES-West) Nighttime Microphysics RGB + daytime True Color RGB images from the CSPP GeoSphere site (above) revealed a curious cloud arc located southeast of the Big Island of Hawai`i (near 150 W longitude) on 30 May 2026. The fact that the typical westward transport of marine boundary layer stratocumulus clouds seemed to abruptly halt to the west of that cloud arc caused this blog post author to immediately wonder “What the heck is this?” — and assign it to the aptly-named “What the heck is this?” blog category of seemingly unexplainable meteorological phenomena.

GOES-18 Infrared Window images (above) and Visible images (below) included plots of surface analyses every 6 hours — which depicted a broad inverted trough over the area, although the position and orientation/shape of the analyzed trough axis did not match that of the actual cloud arc feature (those tropical surface analyses were produced by multiple collaborating agencies; surface analyses from NWS Honolulu also showed a trough axis near 150 W longitude).

In a toggle between GOES-18 Visible, Infrared Window and Cloud Top Height images at 1801 UTC (above), the infrared brightness temperatures of the leading edge of the cloud arc were around +8 to +10C, with Cloud Top Height values generally in the 9500-10000 ft range. According to a plot of 1200 UTC rawinsonde data from Hilo (below), those cloud temperature and height values were near the base of the trade wind inversion.

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