An upper level wave swung through the Tennessee Valley causing widespread rainfall, with a deformation band of heavy rain near the Ohio River in central Kentucky. This caused areas of flash flooding in Jefferson County, KY and severe weather in Clinton County, KY.
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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 LMK wrote it up.
An upper level wave swung through the Tennessee Valley causing widespread rainfall, with a deformation band of heavy rain near the Ohio River in central Kentucky. This caused areas of flash flooding in Jefferson County, KY and severe weather in Clinton County, KY. The rainfall set a record for the most rain in Louisville on the day of the Kentucky Derby. The record of 3.15 broke the old record of 2.31 set May 11, 1918. The daily record for May 5th was also broken. The old record of 2.14 was set in 2003.
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 Louisville, KY wrote its last area forecast discussion before the first event at May 5, 1:29 PM EST, 1 hour 50 minutes earlier.
Area Forecast Discussion National Weather Service Louisville KY 229 PM EDT Sat May 5 2018 .Short Term...(This evening through Sunday night) Issued at 215 PM EDT Sat May 5 2018 It's been a steady, rainy Saturday over central Kentucky and parts of southern Indiana. Surface analysis put a weak area of low pressure east of the area with a diffuse boundary along the Ohio River. Interacting with an upper level wave swinging through the TN Valley, a deformation band of rain has pivoted across central Kentucky. Recent radar trends as of 2 pm EDT show the pivot point for this band to be around Louisville, evident by a stagnant area of heavier showers from near Owensboro to LOU to Cincinnati while showers have slowly lifted north/northeast across south-central Kentucky. In the near term, expect showers to continue through early to mid evening. Some filling in is likely across north central Kentucky. As the forcing with this system moves east this evening, expect a gradual weakening of the shower activity and a slow progression eastward. The precipitation won't completely end until after sunset but coverage should begin decrease after 5 pm or so. Additional rainfall amounts will be light, except in the stalled band along the Ohio River, and down near the TN border, where another 0.25 inch is expected. Locally higher amounts possible. Temperatures will remain steady in the 60s. Late this evening and tonight clouds will begin to clear west to east. The wet soils and light winds at the surface may lead to patchy but dense fog. Soundings indicate that while the near surface winds will be light, just above the surface (>500 ft) there is a decent 10+ kt wind that increases to near 20 kts at 1500-2000 ft. This may preclude widespread fog development, but went ahead and included patchy fog in the forecast for most areas overnight. Lows will be in the mid/upper 50s. Sunday A brief period of high pressure for Sunday morning looks to bring quiet and pleasant start to the day. With some clearing and westerly flow, temperatures should warm into the 70s and lower 80s ahead of another approaching cold front. This front dives in from the north by mid afternoon. HREF mean SBCAPE is 1000-1500 J/kg by afternoon. Soundings show steeper low-level lapse rates and dry mid-level air. If storms fire up along the front and take advantage of daytime heating, a few stronger storms may be possible that could produce gusty winds and hail. The forecast will show precipitation chances increasing after mid afternoon, continuing through mid evening. && .Long Term...(Monday through Saturday) Issued at 225 PM EDT Sat May 5 2018 The focus for next week is shower and storm chances mid to late week. Baggy upper level trough over the region with surface high preswure in teh area should provide a couple drier, more seasonable weather days Monday and Tuesday. Could be a few pop-up daytime heating showers across the higher terrain areas east of I-75, but for the most part, pleasant spring weather is in store with highs in the 70s and lows in the upper 40s to 50s. By Wednesday into Thursday, a more pronounced upper level shortwave digs across the Upper Midwest into lwoer Great Lakes region. This looks to push a cold front through the region and bring showers and the threat of thunderstorms. There remains some timing differences between the various global models but overall the unsettled pattern warrants chance PoPs Wednesday night through Friday. Leaned on the model consensus for temperatures, which look to be at or slightly above normal for early May. && .Aviation...(18Z TAF Issuance) Issued at 120 PM EDT Sat May 5 2018 Guidance all morning has been fluctuating on ceilings this morning, but observations have not...with IFR conditions at KSDF/KLEX and MVFR rains at KBWG. We should see a slow rise at KSDF as the back edge of the heavier rain axis gets close. Timing is a little slower for KBWG/KLEX, with those sites possibly seeing a transition to light fog toward daybreak Sunday. Wind directions are variable and should remain thatway most of this period as there is a light pressure gradient over the region now. May briefly see stronger winds, as small-scale low pressure systems move through our rain shield. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && Short Term...ZT Long Term...ZT Aviation...RJS
Hazardous Weather Outlook National Weather Service Louisville KY 307 PM EDT Sat May 5 2018 INZ078-079-084-089>092-KYZ023>043-045>049-053>057-061>067-070>078- 081-082-061915- Scott-Jefferson-Crawford-Perry-Harrison-Floyd-Clark-Hancock- Breckinridge-Meade-Ohio-Grayson-Hardin-Bullitt-Oldham-Trimble-Henry- Shelby-Franklin-Spencer-Anderson-Woodford-Fayette-Bourbon-Nicholas- Nelson-Washington-Mercer-Jessamine-Larue-Marion-Boyle-Garrard- Madison-Butler-Edmonson-Hart-Green-Taylor-Casey-Lincoln-Logan-Warren- Simpson-Allen-Barren-Monroe-Metcalfe-Adair-Russell-Cumberland- Clinton- Including the cities of Scottsburg, Madison, English, Tell City, Corydon, New Albany, Jeffersonville, Lewisport, Hawesville, Hardinsburg, Brandenburg, Hartford, Leitchfield, Elizabethtown, Shepherdsville, Louisville, La Grange, Bedford, Milton, New Castle, Shelbyville, Frankfort, Georgetown, Cynthiana, Taylorsville, Lawrenceburg, Versailles, Lexington, Paris, Carlisle, Bardstown, Springfield, Harrodsburg, Nicholasville, Winchester, Hodgenville, Lebanon, Danville, Lancaster, Richmond, Morgantown, Brownsville, Horse Cave, Greensburg, Campbellsville, Liberty, Stanford, Russellville, Bowling Green, Franklin, Providence, Scottsville, Glasgow, Tompkinsville, Edmonton, Columbia, Jamestown, Burkesville, and Albany 307 PM EDT Sat May 5 2018 /207 PM CDT Sat May 5 2018/ This hazardous weather outlook is for portions of south central Indiana and Central Kentucky. .DAY ONE...Tonight. There remains a slight chance of thunderstorms through early evening. Heavy rainfall due to slow moving showers is also possible, especially across north central Kentucky and southern Indiana. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Isolated to scattered thunderstorms will be possible Sunday ahead of a cold front. Additional thunderstorms will be possible during the mid to late week period. .SPOTTER INFORMATION STATEMENT... Spotter activation is not needed at this time. INZ076-077-083-061915- Orange-Washington-Dubois- Including the cities of Paoli, Salem, and Jasper 307 PM EDT Sat May 5 2018 This hazardous weather outlook is for portions of south central Indiana. .DAY ONE...Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Isolated to scattered thunderstorms will be possible Sunday ahead of a cold front. Additional thunderstorms will be possible during the mid to late week period. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated. && More information, along with other weather, hydrological and climate information can be found, at weather.gov/louisville. ZT
Special Weather Statement National Weather Service Louisville KY 1236 PM EDT SAT MAY 5 2018 INZ090>092-051730- Floyd-Clark-Harrison- 1236 PM EDT SAT MAY 5 2018 ...SLOW MOVING SHOWERS PRODUCING HEAVY RAIN OVER SOUTHERN INDIANA... At 1234 PM EDT, a slow moving area of showers producing heavy rainfall was located between Floyds Knobs and Memphis, drifting east northeast at 20 mph. Locations impacted include... New Albany, Clarksville, Charlestown, Sellersburg, Galena, Greenville, Lanesville, Crandall, Navilleton and Speed. Plan on heavy downpours with these showers. This may cause localized flooding and ponding on roadways. Expect reduced visibility while driving. Use caution on Interstate 64 and Interstate 65. Do not drive your vehicle through flooded roadways. LAT...LON 3822 8595 3829 8608 3860 8574 3851 8556 TIME...MOT...LOC 1634Z 228DEG 27KT 3837 8585 ZT
Special Weather Statement
National Weather Service Louisville KY
251 PM EDT SAT MAY 5 2018
KYZ030-051930-
Jefferson-
251 PM EDT SAT MAY 5 2018
...SLOW MOVING HEAVY DOWNPOURS OVER LOUISVILLE...
At 248 PM EDT, an area of slow moving showers producing heavy rain
was located over Louisville, moving north at 15 mph.
Expect pockets of heavy rain across Louisville over the next 1-2
hours. This will cause ponding on roadways. Expect reduced
visibility while driving. Do not drive your vehicle through flooded
roadways.
Locations impacted include...
Louisville, St. Matthews, Shively, Graymoor-Devondale, Windy Hills,
Audubon Park, St. Regis Park, Beechwood Village, West Buechel and
Northfield.
LAT...LON 3830 8563 3817 8560 3813 8578 3822 8585
3827 8583 3828 8582 3829 8579 3829 8577
3827 8576 3827 8574 3829 8568 3831 8566
3831 8565
TIME...MOT...LOC 1848Z 162DEG 22KT 3823 8575
ZTSpecial Weather Statement National Weather Service Louisville KY 338 PM EDT Sat May 5 2018 INZ089>092-KYZ023>026-030>033-052045- Perry-Harrison-Floyd-Clark-Hancock-Breckinridge-Meade-Ohio- Jefferson-Oldham-Trimble-Henry- Including the cities of Tell City, Corydon, New Albany, Jeffersonville, Lewisport, Hawesville, Hardinsburg, Brandenburg, Hartford, Louisville, La Grange, Bedford, Milton, and New Castle 338 PM EDT Sat May 5 2018 /238 PM CDT Sat May 5 2018/ ...WIDESPREAD RAIN AND LOCALLY HEAVY DOWNPOURS... A band of rain, heavy in spots, will stretch along and just either side of the Ohio River into the late afternoon hours. Local flooding issues may develop as this rain continues. Also, visibility will be reduced in the heavier downpours. Ponding of water on roadways will occur. Use your headlights and reduce your speed on wet roads. 13
Special Weather Statement
National Weather Service Louisville KY
303 PM CDT SAT MAY 5 2018
KYZ082-052030-
Clinton-
303 PM CDT SAT MAY 5 2018
...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN CLINTON COUNTY...
At 303 PM CDT, a strong thunderstorm was located near Byrdstown,
moving northeast at 40 mph.
Winds in excess of 40 mph and half inch hail are possible with this
storm.
Locations impacted include...
Albany, Cartwright, Snow, Savage, Marlow, Rolan, Nora, Bug, Cannons
Mill and Alpha.
LAT...LON 3663 8524 3682 8512 3678 8502 3675 8500
3673 8502 3671 8501 3670 8502 3669 8502
3668 8501 3667 8501 3666 8500 3663 8500
3662 8498 3663 8511
TIME...MOT...LOC 2003Z 203DEG 36KT 3650 8515
ZTSpecial Weather Statement National Weather Service Louisville KY 404 PM EDT Sat May 5 2018 KYZ034-052115- Shelby- Including the city of Shelbyville 404 PM EDT Sat May 5 2018 ...MODERATE TO HEAVY RAIN IN SHELBY COUNTY... Rainfall rates of 1 to 2 inches per hour have been measured in central Shelby County. Local flooding issues may develop as this rain continues. Also, visibility will be reduced in the heavier downpours. Ponding of water on roadways will occur. Use your headlights and reduce your speed on wet roads. 13
The Louisville radar (KLVX), 30 km away, was scanning. The volume nearest the first event began at 20:19 UTC.
2 flash flood, 1 thunderstorm wind. Local standard time, as filed.
The off ramp from Interstate 65 northbound to Interstate 264 westbound was flooded.
The public reported a tree down near South Clearfork Road.
Police officers blocked the 9th street ramp to Interstate 64 westbound because of standing water over the roadway.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Kentucky in 2018Every state in 2018This day in weather historyWarnings in Kentucky, May 2018
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: 746859, 746863, 746862.