A stationary frontal boundary was located across portions of eastern Kentucky during the afternoon and evening of 8/13/2020. This created the epicenter for shower and thunderstorm development, especially along and south of the boundary, where warm moist air was abundant.
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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 JKL wrote it up.
A stationary frontal boundary was located across portions of eastern Kentucky during the afternoon and evening of 8/13/2020. This created the epicenter for shower and thunderstorm development, especially along and south of the boundary, where warm moist air was abundant. Heavy rains that occurred in Pike and Floyd Counties were enough to lead to some flooding issues, where Dual Pol radar estimated between 1 and 3 inches of rain fell.
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 Jackson, KY wrote its last area forecast discussion before the first event at Aug 13, 7:25 PM EST, 1 hour 6 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED National Weather Service Jackson KY 825 PM EDT Thu Aug 13 2020 .UPDATE... Issued at 800 PM EDT THU AUG 13 2020 23z sfc analysis shows eastern Kentucky still mostly south of a larger synoptic front running west to east near the Ohio River. This is keeping the airmass warm and humid - primed for convection to develop and be sustained. In addition, weak flow aloft is leading to very slow storm movement. In fact, for a time the redevelopment in the east was running along the direction of the stream flow of many of the creeks in Pike County heightening the risk for localized flooding there. Now these storms are starting to fade for most of the area and moving out of the locations of higher concern. Look for the activity to settle down in the next few hours as the instability wanes with sunset. The PoP and Wx grids were updated per the radar trends and the NAMNest near term simulated radar guidance. Temperatures are running in the upper 70s to low 80s for most places, but in the upper 60s and lower 70s where it is raining or just recently saw a storm. Dewpoints, meanwhile, are elevated in the low to mid 70s making for a steamy early evening. Winds, outside of any storms, have been light and variable and will continue that way. Have updated the T/Td grids with the latest obs and trends as well as tweaking the fog for the night considering where the rain has fallen in addition to our typical river valley spots. These updates have been sent to the NDFD and web servers. Look for an update to the text zones and HWO once the storms are gone for the evening. && .SHORT TERM...(This evening through Friday night) Issued at 455 PM EDT THU AUG 13 2020 An upper level low/trough continues to meander across the Lower OH Valley. This was located with a general upper level weakness/upper level trough that extended from the OH Valley into the southeast between an upper level ridge centered near Bermuda and another upper level ridge centered in the Southern Rockies. Meanwhile, a stalled out boundary remains across the OH Valley region near the OH River, though there is a sfc trough/moisture boundary that extends south near or just west of I 75 and then across east TN where it is less defined and then northeast into the central Appalachians. Coverage of convection has been greatest from central KY into the southwest part of the CWA and then into east TN as well as southeast of the area over southwest VA and southern WV. Isolated to scattered showers have developed over the region, but with rather weak forcing and shear have dissipated rather quickly despite modest instability. Relatively warm mid level temperatures and mid level lapse rates around 5.5 C/km seem to be a limiting factor despite low level lapse rates of 7 to 8 C/km and a moist airmass in place with PW of about 1.5 to 1.75 inches. Recent trends/mesoanalysis and convective allowing models support the greatest coverage of convection through this evening in the southeast and southwest portions of the area where MLCAPE is closer to 1500 J/kg versus 1000 J/kg. What storms that develop will be slow moving and at least any storm mergers or outflow interactions could lead to multiple cells and locally heavier rain. Convection should largely wane within a couple of hour past sunset as the upper low/trough remain in place across the lower OH Valley. PW will also gradually increase tonight with the moisture gradient residing near southwest portion of the area. Thus, some convection cannot be ruled out, especially later tonight in the west and north near the stalled boundary/moisture boundary, as the upper low/trough begins to move slowly east in response to a quicker shortwave trough moving along the US/Canadian border and into the Northern Plains. With the anticipated wane in convection, some partial clearing or breaks in the clouds should occur and valley fog and perhaps some stratus in the southeast. Some dense fog is certainly possible, especially for valley locations where breaks in the clouds are most persistent and near where heavier rain falls through this evening. Any fog should dissipate by 9 or 10 AM EDT on Friday. Then, a diurnal increase in convection is anticipated, especially across the south and west as the upper low/trough continues a slow trek east. PW of 1.6 to 1.9 is anticipated and convection should be rather slow moving once again. As has been the case across the Appalachians and OH Valley over the past couple of days, rather high freezing levels should contribute to heavy rainfall rates and any storm interactions/outflow interactions could result in some training of cells. Coverage of convection should be greater than the fast few days. Some of the recent convective allowing models have signals or bullseyes of up to 3 inches or so of rainfall in a rather short period indicative of the potential for locally heavy rainfall and the threat of flooding. This threat continues to be highlighted in the HWO. The upper low/trough will move further east on Friday night with the deeper moisture/higher PW air lingering longest in the east. Showers and isolated storms should linger into the night, with these lingering longest in the eastern portions of the area. Some stratus build down or fog may also develop. The threat for showers and storms that could train will linger on Friday night as PW at least early in the night will be nearing 2 inches. This threat continues to be highlighted in the HWO. .LONG TERM...(Saturday through Thursday) Issued at 520 PM EDT THU AUG 13 2020 Locally heavy showers and thunderstorms wind down on Saturday and a Canadian cold front follows early next week, ushering in a cooler and less humid weather pattern for most of next week. The models remain in broad agreement through the extended. An expansive ~596 dam high will be centered over Arizona Saturday morning while a strong upper level trough extends from the Canadian Arctic to the upper Mississippi Valley. The flow around these large systems will split over the upper Ohio Valley and eastern Great Lakes, resulting in narrow ridging extending northward into the Quebec and broader troughing over the Southeast US. This will allow a weak upper level low to pass over the Ohio Valley on Saturday. This system fills and lifts away from the region on Sunday while the northern trough digs into the eastern CONUS and the western ridge strengthens/retrogrades to near the Great Basin. Ongoing convection is expected across east Kentucky Saturday morning as a weak surface low, mirroring the weak low aloft, rides along a frontal boundary draped across the Commonwealth. A weak cool front, along the back side of the of the low, is expected to slowly push east across the CWA through the day ushering in drier air and bringing widespread rainfall to an end as it passes. There will still be a threat for localized hydro issues east of this boundary, particularly over Pike and adjoining counties, where the highest PWATs will combine with slow storm motions, warm rain processes, and tall, skinny CAPE to to potentially produce torrential downpours through much of the afternoon. Shortwave ridging and weak surface high pressure nose in behind the front Saturday night. Our focus then turns to the digging northern trough which will support a cold front diving into the Ohio Valley on Sunday, reaching eastern Kentucky during the evening or overnight. The front’s relatively quick movement and the lack of deep moisture should limit the duration and intensity of any associated convection. Behind that front, 850 temps are expected to fall back into the 14-16C range on Monday afternoon. Another moisture-starved front could pivot through the area Monday night/Tuesday further suppressing 850 temps. The front stalls east of the area mid-week and becomes a focus point for convection Wednesday and Thursday, especially along and east of the Appalachians. Numerous to widespread showers are forecast to be ongoing Saturday morning but should gradually diminish from west to east during the afternoon and evening. The greatest threat for any torrential downpours and localized flooding issues will likely coincide with peak daytime destabilization across far eastern Kentucky. High temps will probably be suppressed in the upper 70s to lower 80s, coolest in the east where the clouds and rainfall are most persistent. Any leftover showers are expected to give way to partly cloudy skies Saturday night as drier air and surface high pressure noses into eastern KY. Given the widespread rainfall and favorable radiational cooling, expect areas of valley fog to develop Saturday night and early Sunday morning. The approaching cold front will bring the renewed threat for scattered showers or storms by Sunday afternoon. Slightly cooler and less humid conditions are expected behind this front Monday and especially Tuesday. A stray shower or storm can’t be ruled out either day, particularly over the higher terrain, but most areas should remain dry. Better rain chances are expected over eastern areas mid-week as disturbances ride along the stalled front. Temperatures will cool to below normal for Tuesday and Wednesday with highs in the upper 70s/lower 80s and lows in the upper 50s/lower 60s. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 825 PM EDT THU AUG 13 2020 Will hold VCTS or a prevailing TS for another hour or two at a few sites this evening. Then a lull in activity should occur between 03 and 15z, with additional activity anticipated by Friday afternoon. A period of MVFR or IFR will be possible within any of this evening's convection or those of tomorrow afternoon. Otherwise, breaks in the clouds or some partial clearing will take place overnight. This set up should lead to another round of fog - initially in the valleys from 04 to 13z. Some of these vis restrictions will probably spread into the TAF sites after 07z with MVFR and some IFR possible - have included a tempo at most sites for the anticipated worst of it. Look for the fog to lift and dissipate with VFR returning by 14z Friday. Winds, away from any storm, will remain light through the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && UPDATE...GREIF SHORT TERM...JP LONG TERM...GEERTSON AVIATION...JP/GREIF
Hazardous Weather Outlook National Weather Service Jackson KY 411 PM EDT Thu Aug 13 2020 KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120-142315- Fleming-Montgomery-Bath-Rowan-Estill-Powell-Menifee-Rockcastle- Jackson-Pulaski-Laurel-Wayne-McCreary-Whitley-Knox-Bell-Harlan- Elliott-Morgan-Johnson-Wolfe-Magoffin-Floyd-Lee-Breathitt-Knott- Owsley-Perry-Clay-Leslie-Letcher-Martin-Pike- Including the cities of Flemingsburg, Camargo, Jeffersonville, Mount Sterling, Owingsville, Morehead, Irvine, Ravenna, Clay City, Stanton, Frenchburg, Brodhead, Mount Vernon, McKee, Annville, Burnside, Somerset, London, Monticello, Stearns, Whitley City, Corbin, Williamsburg, Barbourville, Middlesboro, Pineville, Cumberland, Harlan, Sandy Hook, West Liberty, Paintsville, Campton, Salyersville, Prestonsburg, Wheelwright, Beattyville, Jackson, Hindman, Pippa Passes, Booneville, Hazard, Manchester, Hyden, Jenkins, Whitesburg, Inez, Coal Run, Elkhorn City, Pikeville, and South Williamson 411 PM EDT Thu Aug 13 2020 This hazardous weather outlook is for portions of eastern Kentucky. .DAY ONE...This evening and tonight. Thunderstorms are possible through this evening. Any thunderstorms could produce locally heavy rainfall. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. Showers and thunderstorms capable of producing locally heavy rainfall and localized instances of flooding are possible Friday into Saturday. Scattered thunderstorms are possible Sunday and Wednesday, mainly during the afternoon and evening hours. An isolated storm is also possible Monday and Tuesday near the Virgina border. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated. JP/GEERTSON
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
Local 911 Dispatch reported heavy rains have led to water across Chloe Road in Pikeville.
Local 911 Dispatch reported that heavy rains have led to water across Ned Fork Road just west of the Craynor community in Floyd County.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Kentucky in 2020Every state in 2020This day in weather historyWarnings in Kentucky, August 2020
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: 901627, 901630.