2.5-minute Target Sector Himawari-9 Visible images (above) and Infrared Window images (below) showed Super Typhoon Dolphin as it reached 150-knot Category 5 intensity (ADT | D-MINT | SATCON) over the West Pacific Ocean (north of the Marshall Islands) at 2100 UTC on 29 July 2026. Mesovortices were evident within the eye — and periodic swirls of mid- to upper-level cloud material appeared to be shedding from the inner edge of the eyewall, suggesting that the mesovortex circulations (which are normally rather shallow) were fairly deep in this case.

Synthetic Aperture Radar (SAR) imagery (below) from around the beginning and ending times of the Himawari-9 animations displayed an apparent break in the eyewall, with hints of narrow wind features that were similar in appearance to the cloud filaments seen in Himawari images. Dolphin was also undergoing an eyewall replacement cycle during this time period.

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1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Visible and Infrared Window images (above) included time-matched plots of SPC Storm Reports — most notably the EF3-rated tornado that moved through the Appleton/Menasha area in northeastern Wisconsin, beginning around 1656 UTC — produced by clusters of thunderstorms on 27 July 2026. Very large hail also occurred in Wisconsin with these storms, including a few reports of 3.00 inches in diameter (and one report of 4.50 inches in diameter, which did not get plotted). Separate thunderstorms also produced large hail, damaging winds and a few tornadoes in the Chicago area.

1-minute GOES-19 Visible and Infrared Window images with an overlay of surface fronts (below) depicted the presence of a surface trough / developing warm front across eastern Wisconsin — the severe thunderstorms were moving southward near or just east of that surface boundary.

A closer look centered near Appleton — airport METAR identifier KATW (below) showed very high dew points across that area, with KATW reporting a dew point of 81 F at 1545 UTC (surface report plot), about an hour before the tornado. As the parent thunderstorm was approaching from the north, pulses of overshooting tops exhibited infrared brightness temperatures as cold as -75 to -78 C (brighter white pixels embedded within dark black regions).

According to a plot of rawinsonde data from Green Bay (below), infrared brightness temperatures of -75 to -78 C represented a significant overshoot of the Most Unstable (MU) air parcel’s Equilibrium Level (EL). The sounding also portrayed a very unstable atmosphere having a MUCAPE value of 4770 J/kg and a Lifted Index of -12 C.

Also of note was the Total Precipitable Water (PW) value of 2.12 inches — according to the SPC Sounding Climatology site, this was a record high PW value for all 27 July 1200 UTC soundings at Green Bay (below).

It is uncommon to see strong tornadoes in the morning in Wisconsin. Looking back from 1950 through April 30 of this year, the prime time for strong tornadoes in Wisconsin is between 2 and 7 pm (CST). Yesterday's tornado began at 10:56 am CST, making it just the 10th to start during that hour.

— Wisconet (@wisconet.bsky.social) 2026-07-28T14:44:03.051Z

===== 29 July Update =====

In toggle between before/after (13 July vs 29 July) Landsat-8 Natural Color RGB images as visualized using RealEarth (above), a faint signature of the tornado damage path (a transition from green shades to tan shades, due to tree/vegetation damage and an increase of structural debris on the ground) could be seen in the vicinity of Appleton, Fox Crossing and Menasha on 29 July.

Similarly, an image slider comparison between Sentinel-2 Optimized Natural Color RGB images on 13 July vs 28 July is shown below — which provided a better view of the vegetation damage swath (most notably near the bottom-center portion of the 28 July image, which is the Menasha area).

BEFORE AND AFTER: A great job by @nearmap showing the damage caused by the EF-3 Appleton-Menasha tornado on Monday. #wiwx pic.twitter.com/J7sw9TvURk

— Scott M (@EODWX5) July 29, 2026

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1-minute Mesoscale Domain Sector GOES-19 (GOES-Eas)t Visible images (above) showed Hurricane Genevieve as it was rapidly intensifying to become a Category 4 storm on 26 July 2026. Low-altitude mesovorticies were very apparent within the eye — and GLM Flash Points depicted intermittent lightning activity within the eyewall of the hurricane.

The corresponding 1-minute GOES-19 Infrared Window images (below) displayed cloud-top infrared brightness temperatures as cold as -75 to -80 C surrounding the eye.

Products from the CIMSS Tropical Cyclones site indicated that Genevieve was moving through an environment of low deep-layer wind shear, and traversing warm water. These favorable factors allowed the hurricane to reach a 135-knot intensity by 0300 UTC on 27 July (ADT | D-MINT | SATCON).

===== 27 July Update =====

Hurricane Genevieve continued to intensify after sunset, reaching 140-knot Category 5 intensity by 0600 UTC on 27 July (0900 UTC NHC discussion).

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1-minute Mesoscale Domain Sector GOES-19 (GOES-East) Visible images (above) and Infrared Window images (below) showed clusters of thunderstorms that produced hail as large as 2.50″ in diameter and wind gusts as high as 92 mph (SPC Storm Reports) across parts of South Dakota on 25 July 2026.

Pulses of overshooting tops exhibited infrared brightness temperatures as cold as -83 C (above) — which represented a significant overshoot of the Most Unstable (MU) air parcel’s Equilibrium Level (EL), according to a plot of rawinsonde data from Aberdeen, South Dakota (below).

1-minute GOES-19 Infrared Window images with plots of GLM Flash Points (below) displayed the abundant lightning activity associated with these severe thunderstorms.

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