This animation of GOES-8 10.7 micrometer InfraRed (IR) imagery shows the development of convection that produced large hail and damaging winds across parts of North Dakota and Minnesota on 08 August 2001. Thunderstorm downburst winds gusted to 114 mph at Grand Forks Air Force Base ND at 01:16 UTC (8:16 PM Central time), 101 mph at Grand Forks ND (KGFK) at 01:26 UTC (8:26 PM Central time), and 79 mph at 01:56 UTC (8:56 PM Central time) at Crookston MN (KCKN). Hourly surface reports are plotted on the imagery, along with reports of hail, wind gusts and wind damage from the listing of preliminary SPC Storm Reports.
An "enhanced-v" cloud top signature became apparent on the GOES-8 IR imagery around 22:40 UTC, as the storm began to produce large hail and damaging winds across northcentral North Dakota. The IR imagery indicated cloud top temperatures as cold at -68 C (dark red enhancement) to the northwest of Grand Forks just prior to the damaging winds at the surface.