For several hours, thunderstorms with heavy rain trained southeast along an axis across western Kentucky into west central Tennessee. The heaviest rainfall and catastrophic flash flooding occurred in west central Tennessee, including Waverly.
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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 PAH wrote it up.
For several hours, thunderstorms with heavy rain trained southeast along an axis across western Kentucky into west central Tennessee. The heaviest rainfall and catastrophic flash flooding occurred in west central Tennessee, including Waverly. In western Kentucky, significant flash flooding occurred near the Tennessee border southeast of Murray. The axis of thunderstorms was aligned with a low level axis of convergence in the surface to 850 mb layer. Storms formed along the convergence axis and then propagated toward the southeast. The atmosphere was moderately unstable even during the early morning hours, with mixed-layer capes estimated to be 1000-1500 J/kg just west of the low level convergence axis. Westerly 850 mb winds around 30 knots along the Mississippi River transported this unstable air toward the low level convergence axis.
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 Paducah, KY wrote its last area forecast discussion before the first event at Aug 21, 5:34 AM CST, 26 minutes earlier.
Area Forecast Discussion National Weather Service Paducah KY 634 AM CDT Sat Aug 21 2021 .UPDATE... Issued at 634 AM CDT Sat Aug 21 2021 Updated aviation section for 12z TAF package. && .SHORT TERM...(Today) Issued at 325 AM CDT Sat Aug 21 2021 MCS over west central and central Missouri continues to push south and southeast early this morning. Current timing brings it into our far western counties around 10z. Current radar shows the portion of the line heading toward our counties has become less organized, which is supported by a decrease in lightning, but more isolated cells have begun to develop. Scattered showers and isolated thunderstorms have been developing the last couple of hours mainly over extreme southern Illinois and the Purchase and Pennyrile regions of west Kentucky. Radar indicates the storms and stronger showers producing heavy rainfall, but movement of the cells eastward has prevented a need for any flood products so far. As coverage increases through daybreak, the main concern will be any training. Latest RAP and HRRR are generally too slow with the movement of the MCS, but have a decent handle with developing convection across our region. Will continue with likely pops across our southwest half of counties through around mid morning, then we should see a decrease in activity until around mid day, and tapered pops down to slights, We then should see an uptick in convection this afternoon, and increased chances back into the 30-40 percent range. Despite the clouds and precipitation, high temperatures are expected to reach the upper 80s. Dew points will be an unpleasant middle to upper 70s, which may mean a few areas could see heat indices touch 100 degrees. .LONG TERM...(Tonight through Friday) Issued at 325 AM CDT Sat Aug 21 2021 By tonight, whatever is left of the front will be lying across the area, resulting in continued rain chances, especially early in the evening. After midnight, chances really dwindle as drier air starts to invade parts of the area with surface high pressure building in, but there will be some areas that will still have small rain chances, mainly the eastern half of the area. By Sunday, there will be a chance of lingering chance for additional showers in the far eastern sections of the CWA, where moisture will be slow to exit the area during the day. Any activity that develops will likely be rather isolated in nature and diurnal. As we start the new week, an upper level ridge, centered over the Arklatex region on Sunday, will begin building into our area. Meanwhile, surface high pressure that will dominate the weather on Sunday, will shift east Sunday night into Monday, which will allow southerly to southwesterly flow to commence across our area. Therefore, while highs on Sunday should reach to around 90 degrees, we will see readings jump into the lower 90s on Monday. It will be mainly dry on Monday, although an increase in moisture out in the Missouri Ozark region may result in a few showers or storms, especially early in the day. Over the next few days, the center of the upper high begins to retrograde a bit and then pivot northward. We will remain on the eastern side of this upper high during this time. Enough moisture will be in the vicinity to where we could see isolated or widely scattered showers or storms, but any surface boundaries that attempt to move into the area, quickly weaken to the point of not be a sufficient focus for any convection. Therefore, will try to keep any PoPs really small considering this and adjust if it appears any frontal activity may aid in higher rain chances. But for now, the signal is just not strong enough to warrant higher PoPs. However, the main topic of conversation this upcoming week will be the heat and humidity at least through mid week. Highs in the lower to mid 90s with dew points in the mid to upper 70s will cause heat index values to rise into the 100 to 105 degree range each day, with some locations reaching even higher than that. The NBM continues to try and keep temperatures Thursday and Friday into the upper 80s to around 90 degrees as the upper high tries to break down. This is also when slightly higher rain chances enter the forecast. && .AVIATION... Issued at 634 AM CDT Sat Aug 21 2021 Very challenging TAF forecast with wide ranging cigs expected. Cigs ranging from low MVFR down to LIFR expected at KPAH/KCGI/KMVN through 15z, then improvement to MVFR to low VFR expected by 18-20z. Vsbys at KMVN should improve from LIFR with fog/shra to VFR by 16z. KCGI/KPAH may see vsbys drop to MVFR mainly with showers. KEVV/KOWB will be primarily VFR through the TAF period. All sites may see isolated to scattered shra/tsra through 03z, and included VCSH or VCTS for time periods with better chances. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && SHORT TERM...RST LONG TERM...CW AVIATION...RST
Hazardous Weather Outlook National Weather Service Paducah KY 352 AM CDT Sat Aug 21 2021 ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087- 100-107>112-114-221000- Jefferson-Wayne IL-Edwards-Wabash-Perry IL-Franklin-Hamilton- White-Jackson-Williamson-Saline-Gallatin-Union-Johnson-Pope- Hardin-Alexander-Pulaski-Massac-Gibson-Pike-Posey-Vanderburgh- Warrick-Spencer-Fulton-Hickman-Carlisle-Ballard-McCracken-Graves- Livingston-Marshall-Calloway-Crittenden-Lyon-Trigg-Caldwell- Union KY-Webster-Hopkins-Christian-Henderson-Daviess-McLean- Muhlenberg-Todd-Perry MO-Bollinger-Cape Girardeau-Wayne MO-Carter- Ripley-Butler-Stoddard-Scott-Mississippi-New Madrid- 352 AM CDT Sat Aug 21 2021 This Hazardous Weather Outlook is for portions of southern Illinois, southwest Indiana, western Kentucky, and southeast Missouri. .DAY ONE...Today and Tonight Scattered thunderstorms will be possible today especially over southeast Missouri, southern Illinois and western Kentucky, possibly lingering into early this evening. Locally heavy rain is likely in some areas, which may lead to minor flooding issues. .DAYS TWO THROUGH SEVEN...Sunday through Friday Small chances of thunderstorms will exist Sunday through Wednesday with better chances entering the forecast later in the week. Main hazards will be lightning and locally heavy rainfall. Maximum afternoon heat index values from 100 to 105 degrees are forecast Monday through Wednesday. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The Paducah radar (KPAH), 24 km away, was scanning. The volume nearest the first event began at 11:57 UTC.
3 flash flood. Local standard time, as filed.
A rainfall total of 3.47 inches was reported during the overnight storms. Flash flooding was observed in the Reidland area. Culverts were overflowing into yards.
Kentucky Highway 1462 was closed at the Clarks River bridge.
Highway 121 south of New Concord was closed due to flooding. In the New Concord area, a bridge on Highway 280 at Panther Creek was closed due to pavement washed away. Rainfall reports of up to 7 inches were received from this event in Calloway County. A co-operative observer in Murray measured a storm total rainfall of 3.45 inches over the past 24 hours.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Kentucky in 2021Every state in 2021This day in weather historyWarnings in Kentucky, August 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: 971615, 975043, 971616.