Residents of midtown Memphis were rudely awakened by howling wind and falling trees early Thursday. A severe thunderstorm packing winds that ranged from around 45 mph to about 85 mph swept across that part of the city between 2:40 a.m. and 2:55 a.m. Hardest hit was the Rhodes College - Hein Park area. Many large trees were uprooted and blown onto houses, power lines (Fig. 1) and blocked streets along and just north of the North Parkway from near University Street eastward to near Hollywood Street. NWS forecasters estimated wind gusts to have been in the 60 mph to 85 mph range in that area.
Scattered trees were toppled while fences and signs were blown over in a larger area where 45 mph to 60 mph wind surrounded the area of concentrated damage. That area of "lighter" damage covered the area from near Watkins eastward almost to Perkins, and from Broad northward to near Macon.
The violent wind gusts were part of something meteorologists call a 'downburst'. Downbursts are the most common kind of damaging weather associated with thunderstorms. An MIT study in the summer of 1984 identified more than 100 small (microburst) downbursts in the greater Memphis area. Fortunately, most downbursts are usually small, very short-lived (5 to 10 minutes), and generate wind gusts weaker than 50 mph. But, wind speeds sometimes top 100 mph. Damage caused by stronger downburst winds is often confused as tornado damage.
Doppler weather radar can provide some indication of downburst wind, but the indications are very subtle, and depend on both distance from the radar and orientation of the wind gusts to the radar. Thursday morning's violent wind was best indicated by patterns in the basic radar (reflectivity)image, but those patterns were slight or subtle, at best. Damage found in midtown after the downburst, and the subtle signature seen in the radar image suggest we experienced a 'twisting' downburst.