Southeast low level wind flow increased ahead of a low pressure system over northern Colorado the afternoon of May 18 2010.  A strong low level southeast jet combined with dynamics of the low to create a favorable environment for severe thunderstorms. By mid afternoon thunderstorms over northern Colorado began to rotate, producing a tornado just south of the Wyoming state line south of Cheyenne.  Severe thunderstorms continued into the evening hours of the 18th producing severe weather across the Nebraska panhandle and extreme southeast Wyoming.

Tornado in LARAMIE, WYOMING
From 18-MAY-10 14:45:00 to 18-MAY-10 14:46:00 (MST-7)
Location: CARPENTER
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter Looking west from Carpenter. Spotter location was Speer Wyoming. Nickel sized hail reported at his location.

Hail in LARAMIE, WYOMING
From 18-MAY-10 14:53:00 to 18-MAY-10 14:54:00 (MST-7)
Location: CHEYENNE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter located in south Cheyenne.

Hail in LARAMIE, WYOMING
From 18-MAY-10 16:00:00 to 18-MAY-10 16:01:00 (MST-7)
Location: ALBIN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Dime sized hail lasted 30 minutes. A total of 1.3 inches of liquid equivilent rainfall fell.

Hail in LARAMIE, WYOMING
From 18-MAY-10 15:04:00 to 18-MAY-10 15:04:00 (MST-7)
Location: CHEYENNE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Intersection of U.S. 85 and Terry Ranch Road.

Hail in LARAMIE, WYOMING
From 18-MAY-10 16:10:00 to 18-MAY-10 16:11:00 (MST-7)
Location: PINE BLUFFS
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Report recieved via E-Spotter.

Hail in LARAMIE, WYOMING
From 18-MAY-10 16:40:00 to 18-MAY-10 16:41:00 (MST-7)
Location: HORSE CREEK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tornado in LARAMIE, WYOMING
From 18-MAY-10 17:00:00 to 18-MAY-10 17:04:00 (MST-7)
Location: PINE BLUFFS
Tornado F-scale: EF0
Reported by: Storm Chaser

Tornado spotteed 2 miles southeast of Egbert Exit. Exit 391 of Interstate 80.

Thunderstorm Wind in LARAMIE, WYOMING
From 18-MAY-10 17:55:00 to 18-MAY-10 17:58:00 (MST-7)
Location: BURNS
Magnitude: 78.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several power poles knocked down.

Flash Flood in LARAMIE, WYOMING
From 18-MAY-10 17:55:00 to 18-MAY-10 18:30:00 (MST-7)
Location: BURNS
Flood cause: Heavy Rain
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Lodge Pole Creek flooding. Water over County Road 149 north of Burns.

Flash Flood in LARAMIE, WYOMING
From 18-MAY-10 17:55:00 to 18-MAY-10 18:30:00 (MST-7)
Location: BURNS
Flood cause: Heavy Rain
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Severe flash flooding southeast of Burns by spotter. A total of 2.32 inches of rainfall in two hours.

Flash Flood in LARAMIE, WYOMING
From 18-MAY-10 18:00:00 to 18-MAY-10 18:30:00 (MST-7)
Location: CARPENTER
Flood cause: Heavy Rain
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Mesonet

Heavy rain lasted 45 minutes. Total of 1.19 inces of rain fell in 45 minutes.

Tornado in LARAMIE, WYOMING
From 18-MAY-10 17:06:00 to 18-MAY-10 17:07:00 (MST-7)
Location: PINE BLUFFS
Tornado F-scale: EF0
Reported by: Law Enforcement

Tornado on ground near County Road 212.

Hail in LARAMIE, WYOMING
From 18-MAY-10 17:06:00 to 18-MAY-10 17:30:00 (MST-7)
Location: BURNS
Magnitude: 0.75 
Property damage: 2.50K
Crop damage: 0.00K
Reported by: Trained Spotter

Ground covered in hail. Damage to siding of house.

Tornado in LARAMIE, WYOMING
From 18-MAY-10 17:15:00 to 18-MAY-10 17:17:00 (MST-7)
Location: PINE BLUFFS
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Brief touchdown of tornado along Interstate 80. No reports of damage.

Flash Flood in LARAMIE, WYOMING
From 18-MAY-10 18:10:00 to 18-MAY-10 18:45:00 (MST-7)
Location: BURNS
Flood cause: Heavy Rain
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Flood damage to a home in Hillsdale.

Tornado in LARAMIE, WYOMING
From 18-MAY-10 17:24:00 to 18-MAY-10 17:25:00 (MST-7)
Location: PINE BLUFFS
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Three tornadoes on the ground at the same time.

Tornado in LARAMIE, WYOMING
From 18-MAY-10 17:21:00 to 18-MAY-10 17:23:00 (MST-7)
Location: PINE BLUFFS
Tornado F-scale: EF0
Reported by: Public

Public report of a tornado along Interstate 80.

Flash Flood in LARAMIE, WYOMING
From 18-MAY-10 18:11:00 to 18-MAY-10 18:40:00 (MST-7)
Location: CHEYENNE
Flood cause: Heavy Rain
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Flooding on access roads between Archer and Hillsdale at exits 370 and 377 of Interstate 80.

Flash Flood in LARAMIE, WYOMING
From 18-MAY-10 18:15:00 to 18-MAY-10 19:00:00 (MST-7)
Location: BURNS
Flood cause: Heavy Rain
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Highway 215 under water west of U.S. Highway 129.

Heavy Rain in LARAMIE, WYOMING
From 18-MAY-10 17:55:00 to 18-MAY-10 19:05:00 (MST-7)
Location: BURNS
Reported by: Newspaper

Five inches of rain fell in 70 minutes.

Flash Flood in LARAMIE, WYOMING
From 18-MAY-10 17:40:00 to 18-MAY-10 18:00:00 (MST-7)
Location: PINE BLUFFS
Flood cause: Heavy Rain
Property damage: 0.10K
Crop damage: 0.00K
Reported by: Mesonet

Flash flooding of low lying areas. 1.53 inches total rainfall.

Flash Flood in LARAMIE, WYOMING
From 18-MAY-10 17:41:00 to 18-MAY-10 18:00:00 (MST-7)
Location: BURNS
Flood cause: Heavy Rain
Property damage: 0.10K
Crop damage: 0.00K
Reported by: Trained Spotter

Flash flooding reported by spotter at Burns exit off of Interstate 80.

Thunderstorm Wind in LARAMIE, WYOMING
From 18-MAY-10 17:41:00 to 18-MAY-10 17:43:00 (MST-7)
Location: BURNS
Magnitude: 78.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Damage to houses and signs in town.

Tornado in LARAMIE, WYOMING
From 18-MAY-10 17:55:00 to 18-MAY-10 18:00:00 (MST-7)
Location: BURNS
Tornado F-scale: EF2
Property damage: 50.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A National Weather Service storm survey determined a tornado that struck Burns Wyoming the evening of May 18 was rated an EF-2. One house lost its roof.  Additionally, the storm that spawned the tornado produced hail the size of golfballs which accumulated to over 3 feet in depth.

Tornado in LARAMIE, WYOMING
From 18-MAY-10 14:40:00 to 18-MAY-10 14:50:00 (MST-7)
Location: CARPENTER
Tornado F-scale: EF0
Reported by: NWS Storm Survey

Tornado crossed the Colorado/Wyoming state line and weakened considerably as it moved north at 240MST. The tornado moved over all rural uninhabited country and no property damage was observed or reported.

Flash Flood in LARAMIE, WYOMING
From 18-MAY-10 17:50:00 to 18-MAY-10 18:30:00 (MST-7)
Location: PINE BLUFFS
Flood cause: Heavy Rain
Property damage: 0.20K
Crop damage: 0.00K
Reported by: Trained Spotter

County Road 219 under water.

Thunderstorm Wind in LARAMIE, WYOMING
From 18-MAY-10 18:00:00 to 18-MAY-10 18:10:00 (MST-7)
Location: PINE BLUFFS
Magnitude: 61.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Center pivots blown over at intersection of County Roads 212 and 158.

Tornado in LARAMIE, WYOMING
From 18-MAY-10 14:41:00 to 18-MAY-10 14:45:00 (MST-7)
Location: CHEYENNE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter reported tornado roping out and dissipating. Spotter location was at end of Christian Road looking southwest.

Hail in LARAMIE, WYOMING
From 18-MAY-10 16:55:00 to 18-MAY-10 16:56:00 (MST-7)
Location: BURNS
Magnitude: 0.50 
Crop damage: 0.30K
Reported by: Mesonet

Two inches of hail accumulation on the ground from event.

Hail in LARAMIE, WYOMING
From 18-MAY-10 17:21:00 to 18-MAY-10 17:23:00 (MST-7)
Location: CHEYENNE
Magnitude: 1.00 
Reported by: Public

Report from public.