sweetapricity/bridgedeck-noaa huggingface dataset:
This stretch of heat was the beginning of an historic heat wave comparable to the intense heat experienced in the 1930's. The high temperature exceeded 100 degrees on the final three consecutive days of the month. At Cape Girardeau, the high was 103 degrees on the 28th, 107 on the 29th, and 105 on the 30th. The high of 107 was the all-time highest temperature on record at the Cape Girardeau airport since records began there in 1960. The previous record was 105 degrees, set on several dates in 1980, 1966, and 1964. Humidity levels were not especially high due to the ongoing drought, so heat index values were within a few degrees of the actual temperature. High pressure at the surface and aloft covered the better part of the country for most of June. Toward the end of the month, the high strengthened and centered itself over the Lower Ohio and Mid-Mississippi Valleys.

Heat in BUTLER, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Heat in CAPE GIRARDEAU, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Heat in MISSISSIPPI, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in BOLLINGER, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in CARTER, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in NEW MADRID, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in PERRY, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in RIPLEY, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in SCOTT, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in STODDARD, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in WAYNE, MISSOURI
From 28-JUN-12 12:00:00 to 30-JUN-12 17:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS
A strong thunderstorm moved through Lake St. Clair.

Marine Thunderstorm Wind in LAKE ST CLAIR (U.S. PORTION), LAKE ST CLAIR
From 02-JUN-12 18:24:00 to 02-JUN-12 18:24:00 (EST-5)
Location: ST CLAIR SHORES
Magnitude: 45.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Buoy

Marine Thunderstorm Wind in LAKE ST CLAIR (U.S. PORTION), LAKE ST CLAIR
From 02-JUN-12 18:30:00 to 02-JUN-12 18:30:00 (EST-5)
Location: ST CLAIR SHORES
Magnitude: 35.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: C-MAN Station

Marine Thunderstorm Wind in LAKE ST CLAIR (U.S. PORTION), LAKE ST CLAIR
From 02-JUN-12 18:15:00 to 02-JUN-12 18:15:00 (EST-5)
Location: NEW BALTIMORE
Magnitude: 46.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS
Clusters of thunderstorms developed during the heat of the afternoon. The storms were located in a hot and unstable air mass to the west of a stationary front that extended from northeast Illinois across Indiana to northeast Kentucky. Amidst weak mid and upper level winds, the severe convection exhibited disorganized/pulse characteristics. South to southwest low-level winds from 10 to 15 knots provided a modest inflow of moisture and instability. Mixed-layer cape values of 1500 to 2000 j/kg and steep low-level lapse rates supported isolated severe wind gusts and hail on a sporadic basis. The storms decreased in number and intensity after sunset as the atmosphere stabilized.

Hail in GIBSON, INDIANA
From 02-JUL-12 15:26:00 to 02-JUL-12 15:26:00 (CST-6)
Location: BUCKSKIN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail was reported on Highway 57.

Thunderstorm Wind in WARRICK, INDIANA
From 02-JUL-12 15:20:00 to 02-JUL-12 15:20:00 (CST-6)
Location: WHEATONVILLE
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Several trees were blown down along Highways 57 and 58 in the extreme northwest part of the county.
A strong upper level system moved through the central U.S. during the day on the 10th.  A cold front entered northwest Iowa during the afternoon of the 10th, and continued across the state during the night.  The airmass became unstable ahead of the front with afternoon highs reaching the low 90s with dewpoints in the low to mid 60s in a narrow band ahead of the cold front.  The atmosphere was weakly sheared with about 35 kts of shear available.  Lifted indices fell to the -4 to -6 C range with CAPE of 1000 to 2000 J/kg.  CAPE in the -10 to -30 C layer of the atmosphere was 400 to 500 J/kg, but hail production was limited by a high freezing level of around 15,000 feet.  Downdraft CAPE was quite high, in the 1000 to 1300 J/kg range.  Precipitable water values increased to 1.7 inches along the front, but rainfall was limited by the fact that the convection was relatively weak given other parameters.  Many of the storms produced 40 to 50 MPH winds.  A few produced severe winds.  One storm in Emmet County toppled a two foot diameter tree and damaged a garage.  Another in Cass County topped trees onto power lines on Olive Street south of Interstate 80.  As the thunderstorms moved through the Bondurant area, lightning struck a house, setting it on fire.

Thunderstorm Wind in EMMET, IOWA
From 10-JUN-12 17:24:00 to 10-JUN-12 17:24:00 (CST-6)
Location: WALLINGFORD
Magnitude: 50.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A two foot diameter tree was blown over.  An small old garage sustained minor structural damage.

Thunderstorm Wind in CASS, IOWA
From 10-JUN-12 19:06:00 to 10-JUN-12 19:06:00 (CST-6)
Location: LORAH
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A large tree and power lines were toppled along Olive Street south of Interstate 80.

Lightning in POLK, IOWA
From 11-JUN-12 00:40:00 to 11-JUN-12 00:40:00 (CST-6)
Location: BONDURANT
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Lightning struck a house in town, setting it on fire.
Slow moving thunderstorms developed along a nearly stationary frontal boundary beneath an upper trof across northern Penobscot county during the evening of the 23rd. An isolated severe thunderstorm developed near Patten with damaging winds. The storm then remained nearly stationary for several hours producing very heavy rains. A localized rainfall total of 6.00 to 8.00 inches was reported with the storm over several hours during the evening...with additional rains falling overnight.  Several roads were washed out along with bridges damaged near Patten.

Flash Flood in PENOBSCOT, MAINE
From 23-JUN-12 22:00:00 to 24-JUN-12 04:00:00 (EST-5)
Location: PATTEN
Flood cause: Heavy Rain
Property damage: 265.00K
Crop damage: 0.00K
Reported by: Law Enforcement

An isolated nearly stationary thunderstorm produced 6.00 to 8.00 inches of rain in less than 4 hours in a localized area near Patten. Route 11 north of Patten was briefly closed due to water over the road. Portions of both Waters Road and Clark Road were washed out with bridge damage resulting in road closures.

Thunderstorm Wind in PENOBSCOT, MAINE
From 23-JUN-12 17:45:00 to 23-JUN-12 17:45:00 (EST-5)
Location: PATTEN
Magnitude: 52.00 EG
Reported by: Fire Department/Rescue

Several trees were toppled on Shin Pond Road by wind gusts estimated at 60 mph.
A perigean spring tide created favorable conditions for salt water flooding along portions of the South Carolina coastline.

Coastal Flood in COASTAL CHATHAM, GEORGIA
From 05-JUN-12 21:44:00 to 05-JUN-12 22:44:00 (EST-5)
Reported by: Broadcast Media

The media reported a road closure due to high water from Lazaretto Bridge Bull River. A maximum tide level of 9.65 ft mllw was measured at the Fort Pulaski tide gage at 9:42 pm.
A weak warm front gradually lifted north through southeast Georgia between high pressure over the Atlantic and a trough of low pressure to the west.  A few thunderstorms developed in deep moisture along and ahead of this weak front.

Thunderstorm Wind in TATTNALL, GEORGIA
From 10-JUN-12 20:07:00 to 10-JUN-12 20:08:00 (EST-5)
Location: COBBTOWN
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A sheriff reported trees down along Woodrow Williams Road.
A weak warm front gradually lifted north through southeast South Carolina between high pressure over the Atlantic and a trough of low pressure to the west. A few thunderstorms developed in deep moisture along and ahead of this weak front.

Thunderstorm Wind in CHARLESTON, SOUTH CAROLINA
From 10-JUN-12 23:30:00 to 10-JUN-12 23:31:00 (EST-5)
Location: ROCKVILLE
Magnitude: 50.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: 911 Call Center

The Charleston County 911 Dispatch reported a tree down along Maybank Highway on Wadmalaw Island.
An isolated thunderstorm formed over the Wind River Mountains and moved into the northern Wind River Basin. The storm produced severe wind gusts that caused tree damage at Crowheart.

Thunderstorm Wind in FREMONT, WYOMING
From 25-JUN-12 20:02:00 to 25-JUN-12 20:12:00 (MST-7)
Location: CROWHEART
Magnitude: 70.00 MG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Mesonet

An automated sensor at Crowheart recorded a thunderstorm wind gust of 81 mph. The storm damaged several healthy trees, snapping off six to eight inch diameter limbs.
An impressive supercell moved across portions of Russell county into northern Barton county.  Several reports of large hail were noted.

Hail in RUSSELL, KANSAS
From 20-JUN-12 16:40:00 to 20-JUN-12 16:41:00 (CST-6)
Location: GORHAM
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Report courtesy of the NSSL Shave project.

Hail in RUSSELL, KANSAS
From 20-JUN-12 16:55:00 to 20-JUN-12 16:56:00 (CST-6)
Location: RUSSELL
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in RUSSELL, KANSAS
From 20-JUN-12 17:00:00 to 20-JUN-12 17:01:00 (CST-6)
Location: GORHAM
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in RUSSELL, KANSAS
From 20-JUN-12 17:06:00 to 20-JUN-12 17:07:00 (CST-6)
Location: RUSSELL
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in RUSSELL, KANSAS
From 20-JUN-12 17:17:00 to 20-JUN-12 17:18:00 (CST-6)
Location: RUSSELL
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in RUSSELL, KANSAS
From 20-JUN-12 17:20:00 to 20-JUN-12 17:39:00 (CST-6)
Location: RUSSELL
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The trained spotter reported that the hail lasted for about 20 minutes.

Hail in BARTON, KANSAS
From 20-JUN-12 18:46:00 to 20-JUN-12 18:47:00 (CST-6)
Location: SUSANK
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BARTON, KANSAS
From 20-JUN-12 19:17:00 to 20-JUN-12 19:18:00 (CST-6)
Location: HOISINGTON
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter
A strengthening upper level low pressure system over the Great Basin brought a strong cold front into Wyoming. The passage of this front brought high wind to the foothills along the east slopes of the Absaroka and Wind River ranges and to Sweetwater County. Gusts to 78 mph were recorded west of Cody and gusts to 62 mph were recorded in the Green Mountains and in Sweetwater County.

High Wind in CODY FOOTHILLS, WYOMING
From 05-JUN-12 20:07:00 to 05-JUN-12 23:57:00 (MST-7)
Magnitude: 68.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

High Wind in LANDER FOOTHILLS, WYOMING
From 05-JUN-12 13:05:00 to 05-JUN-12 16:23:00 (MST-7)
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

High Wind in EAST SWEETWATER COUNTY, WYOMING
From 05-JUN-12 12:39:00 to 05-JUN-12 15:45:00 (MST-7)
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

High Wind in GREEN MOUNTAINS & RATTLESNAKE RANGE, WYOMING
From 05-JUN-12 16:25:00 to 06-JUN-12 01:10:00 (MST-7)
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet
A perigean spring tide created favorable conditions for salt water flooding along portions of the South Carolina coastline.

Coastal Flood in CHARLESTON, SOUTH CAROLINA
From 05-JUN-12 21:42:00 to 05-JUN-12 22:30:00 (EST-5)
Reported by: Social Media

The ramp to South Carolina 61 from Highway 17 was closed due to high water. A few vehicles were stalled in the water.  A maximum tide level of 7.90 feet mllw was measured at the Charleston Harbor tide gage at 954 pm.

Coastal Flood in CHARLESTON, SOUTH CAROLINA
From 05-JUN-12 21:25:00 to 05-JUN-12 22:25:00 (EST-5)
Reported by: NWS Employee

An off duty NWS employee reported a road closure near the intersection of Easy Bay and Morrison Drive. A maximum tide level of 7.90 feet mllw was measured at the Charleston Harbor tide gage at 954 pm.
Southeasterly flow setup a deep layer of moisture over the Florida peninsula that led to thunderstorms developing on seabreeze boundaries in the afternoon producing gusty winds and hail.  One of these storms developed microburst winds.

Hail in HILLSBOROUGH, FLORIDA
From 10-JUN-12 18:16:00 to 10-JUN-12 18:18:00 (EST-5)
Location: CORONET
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

General public reported one inch hail near Plant City.

Thunderstorm Wind in CHARLOTTE, FLORIDA
From 10-JUN-12 16:18:00 to 10-JUN-12 16:18:00 (EST-5)
Location: BERMONT
Magnitude: 61.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A county emergency management damage survey found a 0.2 mile wide damage path that extended for 4 miles, with all the damage blown down in the same direction, to the north northwest. Several trees were uprooted and power poles knocked down. A mobile home sustained minor roof damage, and the roof of a shed was blown 150 feet away. A central pivot irrigation rig was also twisted and damaged by the wind.
A surface front pushing into northern Florida, with a weak mid-level trough swinging across the peninsula provided the support for scattered thunderstorms to develop during the afternoon and early evening hours.  One of these storms produced one inch hail and damaging winds.

Hail in HILLSBOROUGH, FLORIDA
From 14-JUN-12 16:15:00 to 14-JUN-12 16:17:00 (EST-5)
Location: ENON CHURCH
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Broadcast media relayed a report of quarter sized hail at US 92 and Wiggins Road in Plant City.

Thunderstorm Wind in CHARLOTTE, FLORIDA
From 14-JUN-12 16:15:00 to 14-JUN-12 16:15:00 (EST-5)
Location: MURDOCK
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Broadcast media relayed a report of several trees and power lines down at US 92 and Wiggins Road in Plant City.
Thunderstorms that developed in response to an upper level disturbance produced isolated large hail and heavy rainfall as they moved through east-central Wisconsin.

Hail in BROWN, WISCONSIN
From 22-JUN-12 14:32:00 to 22-JUN-12 14:34:00 (CST-6)
Location: ALLOUEZ
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Nickel to quarter size hail fell for about 2 minutes in Allouez.

Hail in BROWN, WISCONSIN
From 22-JUN-12 14:40:00 to 22-JUN-12 14:40:00 (CST-6)
Location: DE PERE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorms produced dime to nickel size hail near De Pere.

Hail in MARINETTE, WISCONSIN
From 22-JUN-12 14:04:00 to 22-JUN-12 14:04:00 (CST-6)
Location: CRIVITZ
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced penny size hail near Crivitz.

Hail in BROWN, WISCONSIN
From 22-JUN-12 14:12:00 to 22-JUN-12 14:12:00 (CST-6)
Location: CORMIER
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced penny size hail in Hobart.

Hail in BROWN, WISCONSIN
From 22-JUN-12 14:20:00 to 22-JUN-12 14:20:00 (CST-6)
Location: ASHWAUBENON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms produced hail up to penny size in Green Bay at Packerland Drive and Hazelwood Lane.

Hail in BROWN, WISCONSIN
From 22-JUN-12 14:22:00 to 22-JUN-12 14:22:00 (CST-6)
Location: PREBLE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorms produced nickel size hail east of Green Bay.

Hail in BROWN, WISCONSIN
From 22-JUN-12 14:24:00 to 22-JUN-12 14:24:00 (CST-6)
Location: PREBLE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Penny size hail fell at The Woods Golf Club in East Green Bay.

Hail in BROWN, WISCONSIN
From 22-JUN-12 14:25:00 to 22-JUN-12 14:35:00 (CST-6)
Location: KOLB
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms produced dime to nickel size hail for about 10 minutes south of Green Bay, near Kolb.

Hail in BROWN, WISCONSIN
From 22-JUN-12 14:50:00 to 22-JUN-12 14:50:00 (CST-6)
Location: SHIRLEY
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced penny size hail at Shirley.

Hail in MANITOWOC, WISCONSIN
From 22-JUN-12 15:58:00 to 22-JUN-12 15:58:00 (CST-6)
Location: SPRING VLY
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms produced penny size hail at the intersection of County Highway X and State Highway 42.

Heavy Rain in CALUMET, WISCONSIN
From 22-JUN-12 15:18:00 to 22-JUN-12 15:33:00 (CST-6)
Location: BRILLION
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms produced an inch of rain, along with pea size hail, during a 15 minute period.
An upper level shortwave helped support an mesoscale convective system as it crossed ohio. This system weakened as it reached eastern Ohio but not before some wind damage was reported. Thunderstorms out ahead of the system also caused flash flooding to areas of western Pennsylvania.

Flash Flood in WASHINGTON, PENNSYLVANIA
From 18-JUN-12 16:45:00 to 18-JUN-12 16:45:00 (EST-5)
Location: PLEASANT GROVE
Flood cause: Heavy Rain
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency management reported several small, unnamed creeks out of their banks. Chapel Hill Road is flooded.

Thunderstorm Wind in WASHINGTON, PENNSYLVANIA
From 18-JUN-12 16:45:00 to 18-JUN-12 16:45:00 (EST-5)
Location: CLAYSVILLE
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency management reported trees down.

Flash Flood in WASHINGTON, PENNSYLVANIA
From 18-JUN-12 17:40:00 to 18-JUN-12 17:40:00 (EST-5)
Location: BUDAVILLE
Flood cause: Heavy Rain
Property damage: 5.00K
Crop damage: 0.00K
Reported by: State Official

State official reported several roads flooded in Donegal Township.
A strong occluded front associated with a 976 mb low in the Gulf of Anadyr approached the Bering Strait coast late on the evening of the 23rd into the early morning of the 24th.  There was a peak wind gust to 62 kt/71 mph at the Wales AWOS during the early morning hours of the 24th.  The wind gusted over 60 mph at times from 2250AKST on the 23rd through 0116AKST on the 24th.  At Teller, there was a peak wind gust to 52 kt/60mph at the Teller AWOS at 0251AKST on the 24th.

High Wind in ST LAWRENCE IS. BERING STRAIT, ALASKA
From 23-AUG-12 22:50:00 to 24-AUG-12 02:51:00 (AKST-9)
Magnitude: 62.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS
A possible dust devil caused minor damage to chicken houses at a farm. It was a clear day with no convection or thunderstorm activity in the area and strong afternoon heating of the surface.

Dust Devil in MILLER, MISSOURI
From 22-AUG-12 13:10:00 to 22-AUG-12 13:10:00 (CST-6)
Location: TUSCUMBIA
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported minor damage occurred at a chicken farm off Highway 52 about 3 miles west of Tuscumbia.  Sheet metal was peeled and blown off a chicken house.  No gradient winds were observed at surrounding ASOS or AWOS stations. This may have been caused by a localized dust devil with winds estimated up to 50 mph.
A weak surface trough dropped across northern Illinois during the evening of June 28th.  Triple digit heat led to extreme instability over the area, and explosive growth of thunderstorms occurred as they moved across the Chicago Metro area dropping large hail.

Hail in KANE, ILLINOIS
From 28-JUN-12 16:07:00 to 28-JUN-12 16:19:00 (CST-6)
Location: ELGIN
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Numerous reports of large hail were received from Elgin.  Average hail was nickel size with the largest up to ping pong ball size.  Hail caused denting in cars and shredded leaves.

Hail in COOK, ILLINOIS
From 28-JUN-12 16:25:00 to 28-JUN-12 16:28:00 (CST-6)
Location: BARTLETT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Hail in COOK, ILLINOIS
From 28-JUN-12 17:53:00 to 28-JUN-12 17:57:00 (CST-6)
Location: ALSIP
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail up to the size of golf balls was reported near Interstate 294 and Cicero Avenue.

Hail in COOK, ILLINOIS
From 28-JUN-12 17:56:00 to 28-JUN-12 17:59:00 (CST-6)
Location: PALOS GARDENS
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in COOK, ILLINOIS
From 28-JUN-12 18:00:00 to 28-JUN-12 18:05:00 (CST-6)
Location: CHICAGO HOWELL ARPT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Golf ball size hail was reported from Midlothian Turnpike and Laramie Boulevard to Cicero Avenue and 147th Street.

Hail in COOK, ILLINOIS
From 28-JUN-12 18:05:00 to 28-JUN-12 18:12:00 (CST-6)
Location: BERGER
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in COOK, ILLINOIS
From 28-JUN-12 18:17:00 to 28-JUN-12 18:20:00 (CST-6)
Location: BURNHAM
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Nickel size hail was reported at 135th Street and Avenue O.

Hail in COOK, ILLINOIS
From 28-JUN-12 18:21:00 to 28-JUN-12 18:25:00 (CST-6)
Location: LANSING
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in COOK, ILLINOIS
From 28-JUN-12 18:33:00 to 28-JUN-12 18:38:00 (CST-6)
Location: ORLAND PARK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in COOK, ILLINOIS
From 28-JUN-12 18:39:00 to 28-JUN-12 18:41:00 (CST-6)
Location: HOMEWOOD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Quarter size hail fell at 183rd Street and Highland Avenue.

Hail in WILL, ILLINOIS
From 28-JUN-12 18:42:00 to 28-JUN-12 18:45:00 (CST-6)
Location: ARBURY HILLS
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Dime size hail fell at 191st Street and La Grange Road.

Hail in WILL, ILLINOIS
From 28-JUN-12 19:17:00 to 28-JUN-12 19:21:00 (CST-6)
Location: CRETE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter