Severe thunderstorms in North Dakota
GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) revealed the circulation of a shortwave aloft (500 hPa analyses) that was moving from the northern Rockies to the southern Canadian Prairie Provinces on 14 June 2018. The approach of this shortwave was helping to enhance large-scale forcing for ascent, as an occluded surface low developed over western North Dakota (surface analyses) — at 1630 UTC, SPC issued a Moderate Risk for severe thunderstorms across far northern North Dakota.A Mesoscale Domain Sector was positioned over that region, providing images at 1-minute intervals; a comparison of “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (below) showed the development of this severe convection, which produced hail as large as 3.0 inches in diameter and 4 tornadoes (NWS Bismarck | NWS Grand Forks). The images include plots of SPC storm reports — just across the US/Canada border, storm reports in southern Saskatchewan/Manitoba can be seen here. Some of these storms exhibited very high radar reflectivity values, as shown here and here.
A larger-scale view of 1-minute GOES-16 Visible images (below) showed well-defined parallel inflow feeder bands moving into the southern flank of the storm approaching Minot (KMOT) and Minot Air Force Base (KMIB) during the 1600-1900 UTC time period. Distinct above-anvil plumes were seen with a number of the stronger storms. The corresponding larger-scale view of 1-minute GOES-16 Infrared images (below) extended past sunset, and showed the final tornado that began around 0324 UTC.