On the second day of a developing heat wave, under a sunny sky, afternoon temperatures reached above 100 degrees across most of northeast Kentucky. For example, Warnock in Greenup County had 104 degrees.  Both Grayson and Ashland reached 103 degrees that Friday afternoon.  Meanwhile, an area of multi-cellular convection had moved out of northern Illinois that morning. It continued to organize and strengthen, as it propagated east and southeast across northern Indiana into western Ohio during the afternoon.  As it moved toward southeast Ohio, it had already formed into a large arch of storms, or bow, with a developing cool pool in its wake.  The temperature contrast between the air ahead of the developing derecho, compared to that in its wake was reaching 30 to 35 degrees. The resultant wind shift in the cool pool resulted in strong moisture convergence on the leading edge of the complex.  This in turn, helped drive the storms further southeast, away from the mid and upper level wind support.  However, the complex was diving right into that hot air that had obtained large convective available potential energy, on the order of 4000 to 5000 j/kg.
The complex crossed the Ohio River into northeast Kentucky just after the hottest time of the day. The outflow, or gust front, had already outraced the rain. There were even brush fires ahead of the gust front.  The wind with the gust front picked up dust and debris in some areas.  The mature system caused the strong gusts to be longer in duration than found in most severe thunderstorms. In some cases the strong wind gusts lasted around 10 minutes.
Wind gusts of 55 to 70 mph were likely with the leading gust front across portions of northeast Kentucky.  In the wake of these stronger winds gusts, the storms only provided around a third of an  inch of rain or less.   Warnock had around a third of an inch of rain, while Ashland measured only 0.14 inches.  Grayson had a meager 0.08 inches.
The wind caused trees and large branches to fall in scattered locations. Roads were temporarily blocked. However, the largest impact was on the electric power grid.  Prolong power outages occurred.  The lack of electricity in the midst of the heat wave, disrupted the daily routines of many citizens for several days.  On the order of 25 to 30 thousand customers were without electricity in these 4 northeast Kentucky counties.  It took some 4 to 7 days to restored electricity in some areas.  Workers trying to restore the electricity had to take frequent breaks due to the heat and the safety equipment they had to wear.  Water and ice were in high demand.  Refrigerated food spoiled.

Thunderstorm Wind in GREENUP, KENTUCKY
From 29-JUN-12 17:45:00 to 29-JUN-12 17:45:00 (EST-5)
Location: KENWOOD
Magnitude: 52.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Trees fell onto utility wires, causing downed poles.  Route 23 was blocked.

Thunderstorm Wind in CARTER, KENTUCKY
From 29-JUN-12 17:41:00 to 29-JUN-12 17:41:00 (EST-5)
Location: OLIVE HILL
Magnitude: 52.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Public

Trees were blown down.

Thunderstorm Wind in GREENUP, KENTUCKY
From 29-JUN-12 17:43:00 to 29-JUN-12 17:43:00 (EST-5)
Location: FLATWOODS
Magnitude: 52.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Large trees were blown down.  Vehicles were damaged.

Thunderstorm Wind in LAWRENCE, KENTUCKY
From 29-JUN-12 18:25:00 to 29-JUN-12 18:25:00 (EST-5)
Location: LOUISA
Magnitude: 52.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Public

Large trees were blown down.

Thunderstorm Wind in CARTER, KENTUCKY
From 29-JUN-12 17:45:00 to 29-JUN-12 17:45:00 (EST-5)
Location: CARTER
Magnitude: 52.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Newspaper

Trees were blown onto utility wires and blocked roads.

Thunderstorm Wind in BOYD, KENTUCKY
From 29-JUN-12 17:50:00 to 29-JUN-12 17:50:00 (EST-5)
Location: ASHLAND
Magnitude: 52.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Newspaper

Large trees and branches were blown down, some fell onto vehicles.  In the aftermath, due to the lack of electricity, several citizens in town used charcoal grills to cook donated food before it spoiled.

Thunderstorm Wind in GREENUP, KENTUCKY
From 29-JUN-12 17:44:00 to 29-JUN-12 17:44:00 (EST-5)
Location: RACELAND
Magnitude: 52.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Public

A hanger roof and door were damaged at the airport.

Thunderstorm Wind in GREENUP, KENTUCKY
From 29-JUN-12 17:25:00 to 29-JUN-12 17:50:00 (EST-5)
Location: SOUTH SHORE
Magnitude: 52.00 EG
Property damage: 750.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Trees and large branches fell in scattered locations throughout the county.  The county had around 250 computer-aided dispatches, a majority of which were weather related.

Thunderstorm Wind in CARTER, KENTUCKY
From 29-JUN-12 17:35:00 to 29-JUN-12 17:50:00 (EST-5)
Location: EBY
Magnitude: 52.00 EG
Property damage: 400.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Large trees and branches fell in scattered locations throughout the county.

Thunderstorm Wind in LAWRENCE, KENTUCKY
From 29-JUN-12 18:05:00 to 29-JUN-12 18:30:00 (EST-5)
Location: GLENWOOD
Magnitude: 52.00 EG
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Large trees and branches fell in scattered locations throughout the county.

Thunderstorm Wind in BOYD, KENTUCKY
From 29-JUN-12 17:48:00 to 29-JUN-12 18:00:00 (EST-5)
Location: SUMMIT
Magnitude: 52.00 EG
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Emergency Manager

Large trees and branches fell in scattered locations throughout the county.