Scattered showers and thunderstorms developed across Middle Tennessee during the afternoon and evening hours on July 17. Heavy rainfall from these thunderstorms led to some localized flooding reports.
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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 OHX wrote it up.
Scattered showers and thunderstorms developed across Middle Tennessee during the afternoon and evening hours on July 17. Heavy rainfall from these thunderstorms led to some localized flooding reports.
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 Nashville, TN wrote its last area forecast discussion before the first event at Jul 17, 5:31 PM CST, 1 hour 41 minutes earlier.
Area Forecast Discussion National Weather Service Nashville TN 631 PM CDT Sat Jul 17 2021 .UPDATE... FOR 00Z AVIATION DISCUSSION. && .DISCUSSION... Broke out late afternoon zone grouping for late afternoon convection chances. Leaded toward consensus blended model solution through next Saturday afternoon. CAMs models continue to not initializing well and leaned toward an overall consensus model blend solution with heavy emphasis on global models through forecast period. Still looks like series of upper level disturbances will impact mid state region as weekend continues to progress, with drier pattern expected to move into mid state region as Tuesday progresses. Upper level disturbance noted moving across eastern portion of mid state region as these late afternoon hours start to approach. Yet another upper level disturbance is expected tonight, and a potential even stronger one as Sun progresses. Additionally, a weak surface frontal boundary will continue to approach mid state region this afternoon from the north and eventually move south of mid state region as Sunday night progresses. Moisture continues to look best across eastern portions late this afternoon and tonight and across southern portions of mid state region on Sunday. A strong thunderstorms here and there may be possible, but not expecting an organized severe weather threat as of this time, Moisture progs continue to suggest convection across eastern portions late this afternoon with better development across southern portions on Sunday. Lows are expected to be around seasonal values through Monday night. Highs are generally expected to be in mid to upper 80s, around 80 Cumberland Plateau Region Sunday and Monday to a return to around seasonal normal values by Tuesday. Total rainfall amounts should range from around 0.50 inch to around 1.5 inches with locally higher amounts around 2 inches possible. By later Monday behind this surface frontal passage, drier air looks like it will still win out and dry conditions should prevail across at least northern portions of mid state region as Tuesday progresses. Model consensus solution still showing by mid portion of next work week main storm track remaining south and west of our area in vicinity of where this surface/low level atmospheric boundary become quasi-stationary. Still expecting dewpoints in the mid 60s by mid week, which will at least bring some relief to recent humidity mid state has been experiencing. At this point after entire mid state experiences dry conditions Wednesday into Wednesday, some showers and thunderstorms may once again be possible on Thursday. However next best chance for showers/storms will come as Friday into at least first part of next weekend progresses as another upper trough axis and weak surface/low level frontal passages approaches mid state region. Latest GFS solution advecting more potential moisture into mid state region than latest ECMWF solution. However, any way you slice it, it looks like weather pattern will support scattered showers and thunderstorms across mid state region once again. Temperatures are expected to be around seasonal normal values with a return of summer humidity. && .AVIATION... 00Z TAF DISCUSSION. Chances for showers and storms will continue this evening, especially for KBNA/KMQY. Some fog will be possible overnight, and cigs look to drop to MVFR/IFR by sunrise and continue through the morning hours. Additional chances for showers and thunderstorms will move in late morning through the afternoon, and may impact terminals, but guidance suggests VFR conditions will return to all terminals by the afternoon. Light south winds are expected. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && DISCUSSION......11 AVIATION........Barnwell
Hazardous Weather Outlook National Weather Service Nashville TN 248 AM CDT Sat Jul 17 2021 TNZ005>011-023>034-056>066-075-077>080-093>095-181030- Stewart-Montgomery-Robertson-Sumner-Macon-Clay-Pickett-Houston- Humphreys-Dickson-Cheatham-Davidson-Wilson-Trousdale-Smith-Jackson- Putnam-Overton-Fentress-Perry-Hickman-Lewis-Williamson-Maury- Marshall-Rutherford-Cannon-De Kalb-White-Cumberland-Bedford-Coffee- Warren-Grundy-Van Buren-Wayne-Lawrence-Giles- 248 AM CDT Sat Jul 17 2021 This Hazardous Weather Outlook is for Middle Tennessee. .DAY ONE...Today and tonight. Scattered to numerous showers and thunderstorms are expected across the area later today and early tonight. Isolated storms could be strong with gusty winds and locally heavy rain...especially across the east. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Scattered to numerous showers and thunderstorms are expected across Middle Tennessee Sunday as well. A few storms could be strong with gusty winds and locally heavy rain. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. 07
Special Weather Statement
National Weather Service Nashville TN
631 PM CDT Sat Jul 17 2021
TNZ028-029-180000-
Wilson TN-Trousdale TN-
631 PM CDT Sat Jul 17 2021
...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN WILSON AND SOUTHWESTERN
TROUSDALE COUNTIES UNTIL 700 PM CDT...
At 630 PM CDT, Doppler radar was tracking a strong thunderstorm near
Lebanon, moving southeast at 20 mph.
Winds in excess of 40 mph will be possible with this storm.
Locations impacted include...
Old Hickory Lake, Lebanon, Hartsville, Tuckers Crossroads and
Dickerson Chapel Recreation Area.
This includes the following highways...
Interstate 40 between mile markers 232 and 245.
Interstate 840 between mile markers 73 and 76.
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.
&&
LAT...LON 3621 8611 3611 8638 3629 8648 3631 8643
3631 8639 3632 8639 3634 8635 3631 8636
3632 8634 3631 8630 3634 8629 3636 8628
3640 8618
TIME...MOT...LOC 2330Z 331DEG 16KT 3625 8628
05Special Weather Statement
National Weather Service Nashville TN
658 PM CDT Sat Jul 17 2021
TNZ028-030-180030-
Wilson TN-Smith TN-
658 PM CDT Sat Jul 17 2021
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN SMITH AND CENTRAL
WILSON COUNTIES UNTIL 730 PM CDT...
At 657 PM CDT, Doppler radar was tracking a strong thunderstorm near
Lebanon, moving southeast at 15 mph.
Winds in excess of 40 mph will be possible with this storm.
Locations impacted include...
Lebanon, Watertown, Cedars Of Lebanon State Park, Tuckers Crossroads
and Gladeville.
This includes the following highways...
Interstate 40 between mile markers 230 and 257.
Interstate 840 between mile markers 70 and 76.
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.
&&
LAT...LON 3613 8595 3601 8638 3624 8648 3631 8616
3629 8613 3632 8611 3634 8604
TIME...MOT...LOC 2357Z 324DEG 12KT 3623 8623
05The Northeast Alabama radar (KHTX), 114 km away, was scanning. The volume nearest the first event began at 01:10 UTC.
3 flash flood. Local standard time, as filed.
Rabbit Trail Road was closed due to flooding and a culvert being washed out.
A low water bridge was flooded and impassable at Bishop Chapel Road near Sweet Home Road.
Two vehicles that drove into flood waters were swept away into a creek on Mockerson Road at Day Road. No injuries were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Tennessee in 2021Every state in 2021This day in weather historyWarnings in Tennessee, July 2021
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: 976240, 976241, 976242.