UPDATE — NASHVILLE: A Tornado Watch has been issued for much of Tennessee until 2 a.m. for the following counties:
BEDFORD, BENTON, CANNON, CARROLL, CHEATHAM, CHESTER, CLAY, COFFEE, CROCKETT, CUMBERLAND, DAVIDSON, DECATUR, DE KALB, DICKSON, DYER, FAYETTE, FENTRESS, FRANKLIN, GIBSON, GILES, GRUNDY,
HARDEMAN, HARDIN, HAYWOOD, HENDERSON, HENRY, HICKMAN, HOUSTON, HUMPHREYS, JACKSON, LAKE, LAUDERDALE, LAWRENCE, LEWIS, LINCOLN, MACON, MADISON, MARSHALL, MAURY, MCNAIRY, MONTGOMERY, MOORE, OBION, OVERTON, PERRY, PICKETT, PUTNAM, ROBERTSON, RUTHERFORD, SHELBY, SMITH, STEWART, SUMNER, TIPTON, TROUSDALE, VAN BUREN, WARREN, WAYNE, WEAKLEY, WHITE, WILLIAMSON, and WILSON
Severe storms and a threat for tornadoes are expected during the afternoon and evening hours across Middle Tennessee later today and into the evening.
This is the same storm system that spawned devastating tornadoes in Iowa yesterday.
A line of thunderstorms with destructive straight-line winds will charge through the Ohio Valley by late morning into the afternoon and trigger the development of clusters of thunderstorms with damaging winds, large hail and a few tornadoes during the afternoon and evening hours across the mid-South including the Tennessee Valley.
There is a moderate risk for severe thunderstorms across northwest Middle Tennessee, and an enhanced risk of severe storms over the remainder of Middle Tennessee, from late this afternoon into tonight. Scattered to numerous showers and thunderstorms are expected to develop late this afternoon and evening across southern Kentucky, then spread southeast across Middle Tennessee into tonight. Damaging winds, large hail, and a few tornadoes are all possible with these storms.
The National Weather Service discussion of possible storms includes this statement:
Environmental parameters strongly favor supercells across this region and very large hail could accompany this activity. In addition, tornado threat will be greatest with these discrete storms that will propagate strongly southeast around 25kt. If this region is not convectively contaminated prior to mid-afternoon there is some concern that a higher tornado threat may be embedded in this region. (The NWS) will monitor mesoscale details and address this concern in later outlooks. Otherwise, multiple severe thunderstorm clusters should evolve across the Mid-South during the evening which should propagate across northern MS/AL with an attendant threat for large hail/damaging winds.
The threat continues Saturday with a slight risk of severe thunderstorms across the southeast half of Middle Tennessee on Saturday afternoon into Saturday evening. A few strong to severe thunderstorms containing damaging winds or large hail will be possible.
Spotter activation is requested this afternoon into tonight across Middle Tennessee.