Another active period of weather set up across central Kentucky and southern Indiana July 17th and 18th, 2023 as multiple waves of showers and thunderstorms moved across the region, bringing damaging straight-line winds, severe hail, and one tornado to the region. The synoptic pattern was fairly consistent (albeit active) during this period, with large-scale mid- and upper-level troughing extending from Hudson Bay down into the Ohio Valley. In the low-levels, a quasi-stationary front extended from the mid-Mississippi Valley across central Indiana and into northern Ohio, with a seasonably warm and unstable air mass present across the Ohio Valley, which was primarily located south of the low-level frontal boundary. The first wave of strong to severe storms developed during the late afternoon hours in the vicinity of the frontal boundary across central Indiana. As these cells morphed into a quasi-linear convective system during the evening hours, the combined cold pool development forced the storms southward into southern Indiana and central Kentucky. Ahead of the line of storms, mixed-layer CAPE on the order of 1500-2500 J/kg and effective bulk shear of 30-40 kt provided a favorable parameter space to sustain strong-to-severe convection. This line of storms ultimately produced sporadic wind damage and near-severe hail across southern Indiana and north central Kentucky, with convection lingering into south central Kentucky overnight before gradually dissipating in the early morning hours on July 18th.
While sporadic convection continued through the morning hours on July 18th, the next main wave of strong and occasionally severe thunderstorms arrived during the early afternoon hours. With unseasonably fast flow continuing aloft, wind shear remained sufficient for multicell clusters and a few supercells to develop across central Kentucky. Instability remained moderate to high, with low-to-mid 70s dewpoints and temperatures in the 80s allowing for the development of 2000-3000 J/kg MLCAPE. This initial wave of cells produced scattered wind damage and hail mainly across the Kentucky Bluegrass. Additionally, a decaying mesoscale convective system coming in from western Kentucky also produced scattered wind damage across southern and central Kentucky. One brief spin-up tornado developed within this line over Marion County, producing EF0 damage. Convection dissipated once the line of storms cleared the area around sunset. As a result of multiple waves of heavy rainfall moving over the same areas, scattered occurrences of flooding were observed across the area, with the most concentrated area of flooding occurring over eastern Jefferson County and Shelby County, Kentucky.

Flash Flood in JEFFERSON, KENTUCKY
From 18-JUL-23 18:15:00 to 18-JUL-23 20:15:00 (EST-5)
Location: AVOCA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Flooding was observed along Arnold Palmer Boulevard in the Lake Forest community. Water levels along the road reached the bottom of car bumpers.

Flash Flood in JEFFERSON, KENTUCKY
From 18-JUL-23 18:35:00 to 18-JUL-23 20:35:00 (EST-5)
Location: MIDDLETOWN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Heavy rain caused Evergreen Road to become impassable between Shelbyville Road and Ridge Road.

Flash Flood in SHELBY, KENTUCKY
From 18-JUL-23 18:55:00 to 18-JUL-23 20:55:00 (EST-5)
Location: MONTCLAIR
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Numerous roads across Shelby County were closed due to high water from heavy rains, including several roads between Shelbyville and Simpsonville.

Flash Flood in MARION, KENTUCKY
From 18-JUL-23 18:59:00 to 18-JUL-23 20:59:00 (EST-5)
Location: GANDERTOWN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: 911 Call Center

Manton Road was closed due to flooding from heavy rainfall.

Hail in JEFFERSON, KENTUCKY
From 18-JUL-23 00:09:00 to 18-JUL-23 00:09:00 (EST-5)
Location: AVOCA
Magnitude: 1.50 
Reported by: Broadcast Media

Ping pong ball sized hail was observed in the Lake Forest community.

Hail in JEFFERSON, KENTUCKY
From 18-JUL-23 00:09:00 to 18-JUL-23 00:09:00 (EST-5)
Location: WOODLAND HILLS
Magnitude: 1.00 
Reported by: Trained Spotter

Quarter sized hail was observed near Middletown.

Hail in JEFFERSON, KENTUCKY
From 18-JUL-23 01:07:00 to 18-JUL-23 01:07:00 (EST-5)
Location: BECKLEY
Magnitude: 1.00 
Reported by: Public

Quarter sized hail was observed in northeastern Jefferson County.

Hail in SHELBY, KENTUCKY
From 18-JUL-23 01:17:00 to 18-JUL-23 01:17:00 (EST-5)
Location: FINCHVILLE
Magnitude: 1.00 
Reported by: Public

Quarter sized hail was observed near Finchville.

Hail in JESSAMINE, KENTUCKY
From 18-JUL-23 02:32:00 to 18-JUL-23 02:32:00 (EST-5)
Location: NICHOLASVILLE
Magnitude: 1.00 
Reported by: Trained Spotter

Quarter sized hail was observed near Nicholasville.

Hail in CASEY, KENTUCKY
From 18-JUL-23 03:38:00 to 18-JUL-23 03:38:00 (EST-5)
Location: RHEBER
Magnitude: 1.00 
Reported by: Public

Quarter sized hail was observed near Dunnville.

Hail in CASEY, KENTUCKY
From 18-JUL-23 03:44:00 to 18-JUL-23 03:44:00 (EST-5)
Location: DUNNVILLE
Magnitude: 1.00 
Reported by: Public

Quarter sized hail was observed in Dunnville.

Hail in CASEY, KENTUCKY
From 18-JUL-23 13:37:00 to 18-JUL-23 13:37:00 (EST-5)
Location: BEECH BOTTOM
Magnitude: 1.00 
Reported by: Trained Spotter

Hail ranging from pea to quarter size was observed northwest of Liberty.

Tornado in MARION, KENTUCKY
From 18-JUL-23 17:54:00 to 18-JUL-23 17:55:00 (EST-5)
Location: PENICKS
Tornado F-scale: EF0
Property damage: 0.00K
Reported by: NWS Storm Survey

Multiple rounds of strong to severe thunderstorms moved through the Marion County area during the afternoon and evening hours on July 18th. A very
brief tornado touched down about 4 miles east of Lebanon, KY near
U.S. 68 just before 7 pm EDT. The storm was moving to the
northeast at 40 mph. There were several trees twisted and snapped
and an older barn was destroyed. Most of the damage was facing to
the east northeast, with some exceptions.
Some of the roof truss from the barn was lofted northeast, but the
board became impaled and was leaning back toward a southwesterly direction.
A horse trailer weighing over 1000 pounds was moved off the block
about 3 feet towards the northwest. This was the highest rated
part of the tornado at 80 mph.
A section of a tree was snapped and facing back to a
southeasterly direction.
The resident of the property showed where the tree line was
behind the barns, and the top of the tree line had about a 20-foot
swath cut out of it.
The top of another metal pole barn exhibited evidence of uplift.
Just beyond the second barn was an uprooted hardwood tree at
the end of the tree line. It was facing north northeast. This was
the last damage observed from both ground and aerial drone survey.

Thunderstorm Wind in MEADE, KENTUCKY
From 18-JUL-23 11:57:00 to 18-JUL-23 11:57:00 (EST-5)
Location: GUSTON
Magnitude: 55.00 EG
Reported by: Emergency Manager

Multiple trees were blown down or uprooted by strong winds, with some trees leaning on homes.

Thunderstorm Wind in CLARK, KENTUCKY
From 18-JUL-23 14:45:00 to 18-JUL-23 14:45:00 (EST-5)
Location: WADES MILL
Magnitude: 51.00 EG
Reported by: Amateur Radio

Trees were blown down by strong winds along White Turley Pike and Wades Mill Road.

Thunderstorm Wind in LOGAN, KENTUCKY
From 18-JUL-23 14:25:00 to 18-JUL-23 14:25:00 (CST-6)
Location: RUSSELLVILLE
Magnitude: 55.00 EG
Reported by: 911 Call Center

Multiple trees were blown down on houses and across roads in Russellville.

Thunderstorm Wind in BUTLER, KENTUCKY
From 18-JUL-23 14:50:00 to 18-JUL-23 14:50:00 (CST-6)
Location: NEEDMORE
Magnitude: 51.00 EG
Reported by: 911 Call Center

Trees were blown down near the intersection of U.S. Route 231 and Little Muddy Church Road.

Thunderstorm Wind in TAYLOR, KENTUCKY
From 18-JUL-23 17:39:00 to 18-JUL-23 17:39:00 (EST-5)
Location: CAMPBELLSVILLE
Magnitude: 52.00 EG
Reported by: Public

Strong winds resulted in multiple trees being blown down in Campbellsville and across Taylor County. Some trees fell onto roads and power lines, and a few structures were damaged by falling trees.

Thunderstorm Wind in JEFFERSON, KENTUCKY
From 18-JUL-23 17:43:00 to 18-JUL-23 17:43:00 (EST-5)
Location: SYLVANIA
Magnitude: 51.00 EG
Reported by: 911 Call Center

A tree was blown down by strong winds in the Pleasure Ridge Park area.

Thunderstorm Wind in MARION, KENTUCKY
From 18-JUL-23 16:54:00 to 18-JUL-23 16:54:00 (EST-5)
Location: LEBANON
Magnitude: 52.00 EG
Reported by: Broadcast Media

Multiple trees were blown down across roads in Lebanon.

Thunderstorm Wind in GARRARD, KENTUCKY
From 18-JUL-23 14:10:00 to 18-JUL-23 14:10:00 (EST-5)
Location: BRYANTSVILLE
Magnitude: 51.00 EG
Reported by: Public

A tree was blown down by strong winds near Bryantsville.

Thunderstorm Wind in GREEN, KENTUCKY
From 18-JUL-23 16:21:00 to 18-JUL-23 16:21:00 (CST-6)
Location: SUMMERSVILLE
Magnitude: 51.00 EG
Reported by: Fire Department/Rescue

Trees were blown down by strong thunderstorm winds near Summersville.