Long-lived MCS tracks across South Dakota, Minnesota and Wisconsin
A large Mesoscale Convective System (MCS) developed and intensified over western South Dakota during the nighttime hours of 10 June – 11 June 2017, evolving into a bow echo that spread a swath of hail and strong winds from central/eastern South Dakota across Minnesota and into Wisconsin and Michigan (SPC storm reports: 10 June | 11 June). Image toggles between Suomi NPP VIIRS Day/Night Band (0.7 µm) and Infrared Window (11.45 µm) at 0734 UTC or 2:34 am Central Time (above) and 0916 UTC or 4:16 am Central Time (below) showed numerous well-defined overshooting tops and cloud-top gravity waves over South Dakota. The coldest cloud-top infrared brightness temperature on the 0916 UTC image was -88º C (dark violet color enhancement). Since the Moon was in the Waning Gibbous phase (at 97% of Full), its ample illumination provided vivid examples of the “visible image at night” capability of the Day/Night Band; several bright white “lightning streaks” were also evident, a signature of cloud top illumination by intense lightning activity. During the subsequent daytime hours of 11 June, GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) images (below) showed the eastward progression of the MCS across Minnesota into western Wisconsin. ** GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing **