Scattered Severe Thunderstorms Across the Northern Plains; Fire Weather Concerns in the Western U.S.

Scattered severe thunderstorms are forecast across central and eastern North Dakota, as well as far northwest Minnesota Saturday (Slight Risk level 2 of 5). Damaging wind gusts are the primary threat. Elevated to critical fire weather conditions will persist through the weekend across the Western U.S. Isolated dry thunderstorms could lead to new fire starts over portions of the northern Rockies. Read More >

Overview

A mesoscale convective system (MCS) tracked south-southeastward across Lake Michigan during the early morning hours of July 29th. Its associated MCV moved to a position to just north of Fort Wayne, Indiana by ~7 AM on the 29th (as the MCS was weakening). WNW flow aloft allowed that MCV to move rather quickly to the east-southeast during the day on the 29th, entering far northwest VA by the middle of the afternoon. During the day, the convection immediately adjacent to the MCV remained sub-severe. By 4:30 PM, a lone thunderstorm near the center of the MCV began rapidly strengthening just to the north of Fredericksburg, Virginia. The storm quickly became a right moving supercell as it tracked from just north of Fredericksburg to near Williamsburg from 4:30 to just after 8 PM before weakening. The environment was characterized by moderate instability but anomalously strong deep layer shear (due to 40-45 knot west-northwesterlies at 500 mb). Extensive straight line wind damage (estimated wind speeds were 70-80 mph) was observed along its track. In addition, hail up to the size of half dollars was observed in the Wakefield forecast area along the track.

Photos
Radar
Storm Reports
Environment

Photos

Storm Damage Photos


Drone footage of damage in Caroline County (source: Caroline County Sheriff's Office)	Slightly difference view of drone footage of damage in Caroline County (source: Caroline County Sheriff's Office)	Caption (source)	Caption (source)

Radar

Selected Loops/Images


Radar Loop from ~4:30 to 8:10 PM in approximately 10 minute increments. On the left is 0.5° Reflectivity and on the right is 0.5° Base Velocity	6:26 PM Radar image of the supercell when it was over Caroline County. On the left is 0.5° Reflectivity and on the right is 0.5° Base Velocity	6:26 PM Vertical Slice of Reflectivity. A bounded weak echo region (BWER) is clearly evident. In addition, there is a 65-70 dbz core to nearly 30,000 feet AGL.	MRMS Low Level Rotation tracks from 3 PM to 9 PM.