Mesolow over Lake Superior
GOES-13 0.63 µm visible channel images (click image to play animation)
A Mesolow developed over Lake Superior today and moved rapidly northeast towards Ontario. As the system moved near Pukaskwa, ON (48.6 N, 86.3 W), winds there shifted from northwest at 3 knots at 1800 UTC to northeast at 5 knots at 1900 UTC to west at 7 knots, gusting to 16 knots at 2000 UTC. (An animation of surface plots overlain on the satellite imagery is here). The mesolow seems to have developed as an interaction with the topography on Isle Royale. Lake Surface temperatures are in the mid-30s, as is typical this time of year, and 850-mb temperatures (as measured at International Falls at 1200 UTC) were around -18 C.
GOES-15 0.62 µm visible channel images (click image to play animation)
GOES-West provided an oblique view of the system development, shown above.
Hat tip to the National Weather Service in Marquette Michigan for first alerting us to this system’s presence!