Tornadoes and large hail in Minnesota and Wisconsin

May 16th, 2017 |

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with SPC storm reports plotted in cyan [click to play animation]

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with SPC storm reports plotted in cyan [click to play animation]

** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

A significant outbreak of severe thunderstorms developed on 16 May 2017, producing damaging winds, large hail and tornadoes from Texas to Wisconsin (SPC storm reports). On the northern end of this outbreak, hail as large as 3.0 inches in diameter fell in northwestern Wisconsin, and a tornado resulted in 1 fatality and at least 25 injuries near Chetek (NWS Twin Cities MN summary). GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) images (above) showed the development of the convective systems; surface-to-cloud-top parallax-corrected SPC storm reports are plotted on the images. Overshooting tops and above-anvil cloud plumes were evident on the visible images, with well-defined “enhanced-V” and “cold/warm thermal couplet” storm top signatures seen on the infrared imagery.

A closer view of the GOES-16 Visible and Infrared Window images (below) provided more detail of the supercell storm-top structure. Note that the pronounced enhanced-V Infrared signature began to develop near the Minnesota/Wisconsin border just before 2100 UTC, which was about 40 minutes before the first Wisconsin hail report of 2.5 inches, and about 90 minutes prior to the fatal Chetek tornado. Since the early 1980s (reference), the enhanced-V satellite signature has been recognized as a reliable predictor of supercell thunderstorms having a high potential to produce either damaging winds, large hail or tornadoes; an automated Enhanced-V / Overshooting Top product (reference) will be available using the ABI instrument on the GOES-R series of satellites..

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with plots of SPC storm reports and hourly surface reports [click to play animation]

GOES-16 Visible (0.64 µm, top) and Infrared Window (10.3 µm, bottom) images, with plots of SPC storm reports and hourly surface reports [click to play animation]

A comparison of GOES-13 (GOES-East) and GOES-16 Infrared Window images (below) demonstrated the advantage of improved spatial resolution (2-km at satellite sub-point with GOES-16, vs 4-km with GOES-13) for identifying features such as cold overshooting tops.

Infrared Window images from GOES-13 (10.7 µm, top) and GOES-16 (10.3 µm, bottom) , with SPC storm reports plotted in cyan [click to play animation]

Infrared Window images from GOES-13 (10.7 µm, top) and GOES-16 (10.3 µm, bottom) , with SPC storm reports plotted in cyan [click to play animation]

True-color Red/Green/Blue (RGB) imagery (below; courtesy of Kaba Bah, CIMSS) offered another view of the storms on a regional scale.

GOES-16 true-color RGB images [click to play animation]

GOES-16 true-color RGB images [click to play animation]


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