Two colliding outflow boundaries merged over east Denver and northwest Aurora at the height of rush hour.  The collision quickly spawned a severe thunderstorm that produced an EF1 tornado, damaging hail, torrential rain and flash flooding.  The tornado touched down in east Denver and west Aurora. The tornado first touched down near Quebec and 6th Ave. It then moved east northeast across the Lowry Campus into the west part of Aurora. The tornado then lifted near Mount Nebo Memorial Park. Some homes had minor roof damage with one former apartment building on the Lowry Campus had more significant roof damage.  The tornado and intense thunderstorm winds uprooted trees, damaging vehicles and blocking roads.
The storm produced torrential rain, 2 to 2.5 inches, much of which fell in less than 30 minutes and resulted in flooded intersections and power outages.  Flash flooding forced the evacuation of a theater at the Cherry Creek Shopping Center, where drifts of hail formed in the parking lot, and flooding set off alarms at the University of Denver's Ritchie Center.  Numerous water rescues were reported as vehicles stalled flooded intersections.  Many stoplights were knocked out.  The water was reportedly 3-feet deep on the South Broadway ramp to Interstate 25.  The bike path along Cherry Creek was inundated with several feet of water at the height of the storm.  The South Platte River crested above flood stage for one hour.  Employees still at work were urged to stay inside but others waded across flooded intersections downtown. About 30 flights had to be diverted from Denver International Airport.

Hail in DENVER, COLORADO
From 24-JUN-15 15:53:00 to 24-JUN-15 15:53:00 (MST-7)
Location: DENVER
Magnitude: 0.88 
Reported by: Trained Spotter

Hail in DENVER, COLORADO
From 24-JUN-15 15:58:00 to 24-JUN-15 15:58:00 (MST-7)
Location: DENVER
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in DENVER, COLORADO
From 24-JUN-15 16:02:00 to 24-JUN-15 16:02:00 (MST-7)
Location: (DEN)DENVER INTL ARP
Magnitude: 1.00 
Reported by: NWS Employee

Hail in DENVER, COLORADO
From 24-JUN-15 15:50:00 to 24-JUN-15 15:50:00 (MST-7)
Location: DENVER
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in DENVER, COLORADO
From 24-JUN-15 15:45:00 to 24-JUN-15 15:45:00 (MST-7)
Location: DENVER
Magnitude: 0.88 
Reported by: Trained Spotter

Hail in DENVER, COLORADO
From 24-JUN-15 16:30:00 to 24-JUN-15 16:30:00 (MST-7)
Location: DENVER
Magnitude: 0.88 
Reported by: Trained Spotter

Hail in DENVER, COLORADO
From 24-JUN-15 16:16:00 to 24-JUN-15 16:16:00 (MST-7)
Location: GLENDALE
Magnitude: 1.50 
Reported by: Trained Spotter

Hail in ARAPAHOE, COLORADO
From 24-JUN-15 16:20:00 to 24-JUN-15 16:20:00 (MST-7)
Location: ARAPAHOE PARK
Magnitude: 1.00 
Reported by: Trained Spotter

Thunderstorm Wind in ARAPAHOE, COLORADO
From 24-JUN-15 18:29:00 to 24-JUN-15 18:29:00 (MST-7)
Location: (BKF)BUCKLEY AIR FORCE BASE
Magnitude: 70.00 EG
Reported by: Broadcast Media

Large trees toppled near 23rd and Galena.

Thunderstorm Wind in WELD, COLORADO
From 25-JUN-15 20:10:00 to 25-JUN-15 20:10:00 (MST-7)
Location: PURCELL
Magnitude: 52.00 MG
Reported by: Trained Spotter

Tornado in DENVER, COLORADO
From 24-JUN-15 15:48:00 to 24-JUN-15 16:10:00 (MST-7)
Location: DENVER
Tornado F-scale: EF1
Reported by: NWS Storm Survey

A tornado touched town near Quebec and 6th Ave and lifted near Mount Nebo Memorial Park. This tornado was a non-supercell tornado. Two outflow boundaries from earlier thunderstorms intersected over eastern Denver and western Aurora. This produced localized convergence and wind shear which likely contributed to the rapid formation of the tornado.

Flash Flood in DENVER, COLORADO
From 24-JUN-15 16:25:00 to 24-JUN-15 20:15:00 (MST-7)
Location: DENVER
Flood cause: Heavy Rain
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Torrential rainfall, from 2 to 2.5 inches, flooded intersections up to 3 feet of standing water at several intersections including:  6th Ave and Lowell, Broadway and Interstate 25, as well as parts of Speer Blvd along Cherry Creek.