A low amplitude short wave trough and associated surface frontal boundary moved southeast out of the Lower Ohio Valley across the Southern Appalachian producing widespread reports of large hail along with some wind damage; mainly south of Interstate 40.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MRX wrote it up.
A low amplitude short wave trough and associated surface frontal boundary moved southeast out of the Lower Ohio Valley across the Southern Appalachian producing widespread reports of large hail along with some wind damage; mainly south of Interstate 40.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Morristown, TN wrote its last area forecast discussion before the first event at Mar 21, 1:21 PM CST, 2 hours 9 minutes earlier.
Area Forecast Discussion National Weather Service Morristown TN 321 PM EDT Tue Mar 21 2017 .SHORT TERM (This Evening through Wednesday)...HRRR model continues to show confidence in an area of convection moving east southeast across the area late this afternoon/early evening, mainly along and south of interstate 40. Strong 300 mb jet over the Ohio Valley will place east Tenessee under the favored Right entrance region of the jet. This forcing with increasing instability will produce severe thunderstorms. The dry air in the mid-levels (DCAPE up to 1200 J/kg and DCP values near 3) combined with good hail CAPE (values near 1000 J/kg and SHIP up to 2.5) will set the stage for damaging winds and large hail. Main threat remains over southeast Tennessee and southwest North Carolina. Timeframe for severe weather is between 20-23Z. Give the hail/wind parameters, hail sizes up to Golfball size and wind speeds to 70 mph are possible. Forcing will move east of the area this evening with only showers anticipated by 03z, then dissipated around 06Z. Afterwards, plenty of the dry air to clear sky out for Wednesday morning. Severe thunderstorm Watch will be out soon. .LONG TERM (Wednesday Night through Tuesday)... Long term starts out dry as slow moving cold front finally pushes through the area. Models are in fair agreement that the boundary, just south of the area will continue to slightly elevate pcpn chances over far SE TN and all of our SW NC counties through Thursday. Middle level ridge amplifies across the area Friday into Saturday with daytime highs climbing about 10 degrees above normal by Saturday. Models are in fair agreement on the strength and location of the next low pressure system Saturday and Sunday, although ECMWF is a bit more progressive with the frontal boundary pushing it through the area by Sunday evening while the GFS is much slower. Current POP fcst is a blend of both solutions which brings in higher POP by Saturday afternoon and holds onto those POPs until overnight Sunday. Based on current models and ensemble fcsts, suspect greatest pcpn chances will likely be on Sunday. A secondary system begins to move into the area pretty quickly behind the weekend system on Monday. Once again models remain in fair agreement on the track of low center and associated cold front with our area falling under a broad area of low pressure out ahead of the front and continued chance for showers and maybe a thunderstorm Monday and Tuesday as the front seems to stall across the area late in the period. With steady low level warm advection, area will likely see daytime high temperatures remain at about 10 degrees above normal for the early part of the new work week. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 52 64 43 58 / 80 10 10 20 Knoxville McGhee Tyson Airport, TN 46 59 39 57 / 70 0 10 10 Oak Ridge, TN 45 59 40 60 / 70 0 10 10 Tri Cities Airport, TN 41 56 30 58 / 30 0 10 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. &&
Hazardous Weather Outlook National Weather Service Morristown TN 325 PM EDT Tue Mar 21 2017 NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002- 005-006-008-221930- Cherokee-Clay-Scott TN-Campbell-Claiborne-Hancock-Hawkins- Sullivan-Johnson-Morgan-Anderson-Union-Grainger-Hamblen- Northwest Cocke-Cocke Smoky Mountains-Northwest Greene- Southeast Greene-Washington TN-Unicoi-Northwest Carter- Southeast Carter-Roane-Loudon-Knox-Jefferson-NW Blount- Blount Smoky Mountains-North Sevier-Sevier Smoky Mountains- Sequatchie-Bledsoe-Rhea-Meigs-McMinn-Northwest Monroe- Southeast Monroe-Marion-Hamilton-Bradley-West Polk-East Polk-Lee- Wise-Scott-Russell-Washington- 325 PM EDT Tue Mar 21 2017 /225 PM CDT Tue Mar 21 2017/ This Hazardous Weather Outlook is for portions of Southwest North Carolina...East Tennessee and Southwest Virginia. .DAY ONE...This Afternoon and Tonight ...Enhanced Risk of Severe Thunderstorms across southeast Tennessee and southwest North Carolina for late this Afternoon and early Evening... Thunderstorms will develop across the area this afternoon into this evening. Some of these storms will be severe...mainly in areas south of I40. Large hail and damaging straight-line winds will be the primary threats. Hail up to Golfball size and winds to 70 mph are possible with the stronger thunderstorms. The main time-frame for severe weather will be between 4 and 8 pm ET. .DAYS TWO THROUGH SEVEN...Wednesday through Monday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon and evening.
Special Weather Statement National Weather Service Morristown TN 1143 AM EDT Tue Mar 21 2017 NCZ060-061-TNZ035-036-067>069-071>074-081>087-098>102-220000- Cherokee-Clay-Morgan-Anderson-Roane-Loudon-Knox-NW Blount- Blount Smoky Mountains-North Sevier-Sevier Smoky Mountains- Sequatchie-Bledsoe-Rhea-Meigs-McMinn-Northwest Monroe- Southeast Monroe-Marion-Hamilton-Bradley-West Polk-East Polk- Including the cities of Murphy, Hayesville, Wartburg, Clinton, Oak Ridge, Kingston, Lenoir City, Knoxville, Maryville, Cades Cove, Sevierville, Gatlinburg, Dunlap, Pikeville, Dayton, Decatur, Athens, Madisonville, Coker Creek, Jasper, Chattanooga, Cleveland, Benton, and Ducktown 1143 AM EDT Tue Mar 21 2017 /1043 AM CDT Tue Mar 21 2017/ ...Enhanced Risk of Severe Thunderstorms across southeast Tennessee and southwest North Carolina for late this Afternoon and early Evening... An area of thunderstorms will develop across middle Tennessee this afternoon then move east southeast into the southern Plateau and southeast Tennessee between 4 and 6 pm ET. This area of storms will continue to move east into southwest North Carolina by 7 pm. Areas south of interstate 40 have the great threat of severe storms today. The main concern from these storms will be large hail up to Golfball size and damaging winds up to 70 mph. Please listen to NOAA Weather Radio or your local media for the latest updates on this situation.
Special Weather Statement
National Weather Service Morristown TN
415 PM EDT TUE MAR 21 2017
TNZ084-099-100-212100-
Bradley TN-Hamilton TN-Meigs TN-
415 PM EDT TUE MAR 21 2017
...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN BRADLEY...
SOUTHWESTERN MEIGS AND NORTHEASTERN HAMILTON COUNTIES UNTIL 500 PM
EDT...
At 414 PM EDT, Doppler radar was tracking a strong thunderstorm near
Soddy-Daisy, or 13 miles south of Dayton, moving southeast at 10 mph.
Half inch hail and winds in excess of 40 mph will be possible with
this storm.
Locations impacted include...
Cleveland, Soddy-Daisy, South Cleveland, Shady Grove, Hopewell and
Sale Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
A severe thunderstorm watch remains in effect until 1100 PM EDT for
eastern Tennessee.
LAT...LON 3511 8493 3527 8516 3536 8511 3532 8480
3531 8479
TIME...MOT...LOC 2014Z 297DEG 8KT 3530 8509
05/MASpecial Weather Statement
National Weather Service Morristown TN
458 PM EDT TUE MAR 21 2017
TNZ083>085-212145-
Rhea TN-Meigs TN-McMinn TN-
458 PM EDT TUE MAR 21 2017
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN RHEA...CENTRAL MEIGS AND
NORTHWESTERN MCMINN COUNTIES UNTIL 545 PM EDT...
At 458 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Dayton to 13 miles northeast of
Soddy-Daisy. Movement was east at 10 mph.
Half inch hail and winds in excess of 40 mph will be possible with
these storms.
Locations impacted include...
Dayton, Decatur, Graysville, Old Washington, Hillsview and Big
Spring.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
A severe thunderstorm watch remains in effect until 1100 PM EDT for
eastern Tennessee.
LAT...LON 3539 8503 3541 8502 3544 8506 3543 8507
3544 8509 3543 8510 3544 8511 3545 8510
3545 8511 3554 8499 3560 8459 3537 8478
TIME...MOT...LOC 2058Z 272DEG 7KT 3550 8497 3542 8503
05/MAPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
525 PM EDT TUE MAR 21 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0508 PM HAIL 2 W HOPEWELL 35.23N 84.94W
03/21/2017 E1.25 INCH BRADLEY TN AMATEUR RADIO
QUARTER TO HALF DOLLAR SIZE HAIL
0515 PM HAIL CLEVELAND 35.07N 82.53W
03/21/2017 E1.75 INCH GREENVILLE SC TRAINED SPOTTER
PING PONG TO GOLF BALL SIZE HAIL
0515 PM HAIL CLEVELAND 35.07N 82.53W
03/21/2017 E1.50 INCH GREENVILLE SC AMATEUR RADIO
PING PONG BALL SIZE HAIL
&&
MBLACKPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MORRISTOWN TN
529 PM EDT TUE MAR 21 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0517 PM HAIL N CLEVELAND 35.07N 82.53W
03/21/2017 E1.75 INCH GREENVILLE SC BROADCAST MEDIA
MEDIA REPORT OF PING PONG SIZE HAIL IN NORTH CLEVELAND
&&
MBLACKThe Northeast Alabama radar (KHTX), 59 km away, was scanning. The volume nearest the first event began at 21:28 UTC.
16 thunderstorm wind, 15 hail. Local standard time, as filed.
Power lines were reported down across the county mainly north of Whitwell. Also, roof damage was reported at a house in New Hope.
Several trees were reported down from north of Dunlap to the county line. Dime size hail was also reported in the area.
Several trees and power lines were reported down.
Quarter to half dollar size hail reported by amateur radio.
Spotter reported ping pong to golf ball size hail in Cleveland.
Quarter size hail reported in Cleveland.
Power lines were reported down.
Public reported golf ball size hail.
Hail stripped leaves, dented cars, damaged shingles and broke car windows.
Quarter size hail.
Golf ball size hail was reported along Buttermilk Road.
Nickel to quarter size hail was reported near Dogwood Shores Estates.
Quarter size hail was reported.
Quarter size hail was reported.
Half dollar size hail was reported.
Two inch diameter hail was reported.
Wind speeds were estimated at 60 to 70 mph.
Golf ball size hail was reported near Clinton Highway and Schaad Road.
Fifteen to twenty structures were damaged from a downburst in the Dallas Bay area of the county along Chickamauga Lake. The area which suffered the most damage is along Barkley Lane where a roof was removed from a single family home. Another home was partially blown off its foundation.
Several trees were reported down along the interstate.
Ping pong size hail was reported.
Power lines were reported down.
A tree was reported down near mile marker 359 on Interstate 40.
One tree was reported down.
A few trees and power lines were reported down across portions of the county.
A few trees were reported down across the county. One was across County Road 442 and another at County Road 750 near County Road 604.
Numerous trees were reported down across the county.
Numerous trees were reported down across the county.
A downed tree was blocking Happy Valley Road and Highway 129 near Chilhowee Lake.
Nickel to quarter size hail was reported near Dogwood Shores Estates.
Two large limbs were reported down near Cades Cove.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Tennessee in 2017Every state in 2017This day in weather historyWarnings in Tennessee, March 2017
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 680587, 680588, 680589, 723802, 723803, 723801, 680590, 723804, 723805, 723787, 680578, 680579, 680580, 680581, 680582, 680583, 680596, 680584, 680591, 680592, 680585, 680593, 680597, 680598, 680600, 680594, 680595, 680599, 680602, 680586, 680601.