The trailing end of a 500 mb shortwave trough over the Great Lakes region extended down into the lower Ohio Valley. Scattered slow-moving thunderstorms near the trough axis produced isolated flash flooding.
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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.
The trailing end of a 500 mb shortwave trough over the Great Lakes region extended down into the lower Ohio Valley. Scattered slow-moving thunderstorms near the trough axis produced isolated flash flooding.
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 19, 2:29 AM CST, 2 hours 16 minutes earlier.
Area Forecast Discussion National Weather Service Paducah KY 329 AM CDT Thu Aug 19 2021 .SHORT TERM...(Today through Saturday night) Issued at 325 AM CDT Thu Aug 19 2021 The main concerns in the near term include the potential for showers and thunderstorms in addition to the potential for overnight fog. Forecast confidence in the general synoptic scale pattern is relatively good, but the details are less certain given the uncertainties inherent in such a late summertime convective regime. First off, visibilities continued to gradually decline overnight as areas of fog developed, especially across portions of southern Illinois and southeast Missouri. Expect this trend to continue into daybreak and further east with time. While widespread dense fog isn't expected, there could be some patchy dense fog by the morning commute. Models also suggest the potential for fog tonight as well, so we maintained that from the previous forecast. Additionally, scattered showers and isolated thunderstorms persisted mainly across portions of southwest Indiana and western Kentucky overnight. That activity may linger into the morning hours, in particular across western Kentucky. By this afternoon, weak surface high pressure will bring slightly drier air through the column from the north, so any shower and thunderstorm chance should be suppressed into southern portions of southeast Missouri and western Kentucky. Tonight looks largely dry, except for the potential for some late night activity across mainly southeast Missouri. Then from Friday into Saturday, energy extending south from a shortwave trough progressing from the Plains into the Upper Midwest will result in the slow west to east progression of a zone of higher moisture content air through the region. This will yield the potential for scattered showers and thunderstorms through the period. Better chances should be focused across southern and western portions of the area on Friday, expanding further east by Friday night and Saturday. With specific humidity values greater than 2 standard deviations above climatological norms and precipitable water values forecast in excess of 2 inches, locally heavy rain will be the primary concern with thunderstorm activity. Weak wind fields aloft should largely mitigate the potential for severe storms, although an increase in deep layer shear may yield a slightly increased potential for stronger storms on Saturday. Precipitation totals through Saturday night will be highly variable, ranging from perhaps less than a half inch across portions of the Wabash River Valley to possibly 1 to 2+ inches in localized downpours elsewhere. Temperatures will feel the effects of the increased sky cover and humidity. Highs are forecast to range through the middle 80s today, then the middle to upper 80s Friday and Saturday. Lows through the period should range from the upper 60s to lower 70s. .LONG TERM...(Sunday through Wednesday) Issued at 325 AM CDT Thu Aug 19 2021 During the latter half of the weekend, an upper level high will be sitting to our south. Heights will build slightly over our area as this upper high strengthens a bit. At the surface, there is a weak washed out boundary that is laid out across the southern part of the area. This feature combined with some decent moisture could yield a few showers or storms on Sunday, but at this juncture, sure does not seem real impressive. This idea is supported by the latest GFS and ECMWF ensemble members. We should see high temperatures a bit warmer on Sunday, to where most locations should be a degree or two either side of 90. By Monday, the upper ridge will build a little bit further into our area and cause our high temperatures to rise into the lower 90s area wide. Any substantial convection should be confined to areas well to our north, where the better upper flow will be positioned. The latest NBM kept some slight chance PoPs in our far east. Cannot completely rule an afternoon shower or thunderstorm in these areas given the moisture in place and being on the eastern periphery of the upper high. This lines up well with the latest GEFS/ECMWF ensemble means. As we head into Monday night and Tuesday, the upper high begins to retrograde westward to where our area will be residing on its eastern fringes by mid week. NBM PoPs for Tuesday suggest a dry day with southerly flow at the surface and not much to focus much convection on, other than maybe isolated heat of the day storms, especially given that deep moisture is still relatively in place across the area. The heat will not be going anywhere fast though, as lower 90s seem like a decent bet both Tuesday and Wednesday, going with a consistency type forecast. Given the high dew points forecast across the area on Tuesday, combined with highs in the lower 90s, we could see heat index values back up into the 100 to 105 degree range. By Wednesday, the center of the upper high will be positioned over desert southwest into the southern Plains. A weak surface front is progged to sag south into the area by then, which should put allow for a better chance for favorable sector for shower and thunderstorm development. This is reflected in the latest NBM PoPs which broad brushes the area with small rain chances for Wednesday into Wednesday night. Given the synoptic scenario and looking at the latest ensembles and ensemble means, see no reason to alter this much. && .AVIATION... Issued at 1211 AM CDT Thu Aug 19 2021 A disturbance aloft will continue to move eastward and eventually away from our region, taking much of the shower and tstm activity with it. However, there were some model indications that more (primarily shower) activity could fire up in the Pennyrile region of KY and southwestern IN overnight. As the atmosphere cools, an IFR cig is expected to form, initially in southern reaches of the region, with IFR and some LIFR conditions spreading to the rest of the region by daybreak. As anticipated lows cool into the upper 60s to 70, and winds go dead calm, fog is likely overnight, though widespread dense fog is not necessarily anticipated. Conditions will improve toward VFR Thu morning, with cigs breaking up by late afternoon. Though there may be some shower or even tstm activity around in the day Thu, probabilities were low enough to leave out of the TAFs. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && SHORT TERM...RJP LONG TERM...CW AVIATION...DB
Hazardous Weather Outlook National Weather Service Paducah KY 444 AM CDT Thu Aug 19 2021 ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087- 100-107>112-114-201000- 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- 444 AM CDT Thu Aug 19 2021 This Hazardous Weather Outlook is for portions of southern Illinois, southwest Indiana, western Kentucky, and southeast Missouri. .DAY ONE...Today and Tonight A small chance of thunderstorms continues today, especially across southern portions of southeast Missouri and western Kentucky. Lightning and locally heavy rain are the main concerns. .DAYS TWO THROUGH SEVEN...Friday through Wednesday There is a chance of thunderstorms across most of the area Friday into Saturday. A small chance lingers into Sunday, then returns on Wednesday. Locally heavy rainfall and lightning will be the primary hazards. However, locally strong storms cannot be ruled out on Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated. RJP/CW
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PADUCAH KY
452 AM CDT THU AUG 19 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0440 AM HEAVY RAIN GRANDVIEW 37.93N 86.98W
08/19/2021 M2.54 INCH SPENCER IN BROADCAST MEDIA
RAINFALL TOTAL SINCE MIDNIGHT.
&&
RJPThe Evansville,IN radar (KVWX), 73 km away, was scanning. The volume nearest the first event began at 10:45 UTC.
1 flash flood. Local standard time, as filed.
Numerous roads were underwater in the southern part of the county, including State Route 545 near New Boston, County Road 200 West near Rockport, State Route 161 near Richland City, and County Road 200 North near Reo. An observer in Grandview measured 2.54 inches between midnight and sunrise.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Indiana in 2021Every state in 2021This day in weather historyWarnings in Indiana, 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: 971610.