A diffuse and weak mid-level trough drifted across the eastern Great Lakes during the afternoon and evening, with a weak inverted trough at the surface extending from the Middle Atlantic states into western New York. Daytime heating resulted in moderate instability, although mid-level lapse rates were poor. Very weak flow through the low and mid-levels provided little to no shear. Scattered thunderstorms developed by midafternoon, with new storm development and subsequent storm motion then driven mainly by outflow boundaries, resulting in slow and chaotic storm motion over the event. A few storms pulsed high enough and long enough to produce severe weather. A few storms also latched onto outflow boundaries and remained nearly stationary or trained for one to two hours, producing isolated flash flooding from northeast Cattaraugus County to the Buffalo Metro area.

Flash Flood in CATTARAUGUS, NEW YORK
From 15-AUG-20 18:53:00 to 15-AUG-20 19:30:00 (EST-5)
Location: LIME LAKE
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Marble Road and Potter Road were reported to be washed out by law enforcement.

Thunderstorm Wind in ERIE, NEW YORK
From 15-AUG-20 18:36:00 to 15-AUG-20 18:36:00 (EST-5)
Location: KENMORE
Magnitude: 51.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Trees were reported down on Frontenac Street.

Hail in ERIE, NEW YORK
From 15-AUG-20 18:17:00 to 15-AUG-20 18:17:00 (EST-5)
Location: (BUF)GTR BUFFALO INT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Heavy Rain in ERIE, NEW YORK
From 15-AUG-20 19:37:00 to 15-AUG-20 19:37:00 (EST-5)
Location: BUFFALO
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Rainfall of 2.12 inches was reported.

Flash Flood in ERIE, NEW YORK
From 15-AUG-20 19:26:00 to 15-AUG-20 21:00:00 (EST-5)
Location: BUFFALO
Flood cause: Heavy Rain
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Public

Hertel Avenue near Homer Avenue was reported to have one foot of water on it with video indicating so on Snapchat, as well.

Flash Flood in ERIE, NEW YORK
From 15-AUG-20 19:30:00 to 15-AUG-20 21:00:00 (EST-5)
Location: BUFFALO
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Walden Avenue and Sycamore Street was closed due to flash flooding.

Flash Flood in ERIE, NEW YORK
From 15-AUG-20 19:30:00 to 15-AUG-20 21:00:00 (EST-5)
Location: BUFFALO
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Elmwood Avenue and Ferry Street was closed due to flash flooding.

Flash Flood in ERIE, NEW YORK
From 15-AUG-20 19:30:00 to 15-AUG-20 21:00:00 (EST-5)
Location: FERRY VLG
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Flash flooding closed Niagara Street at Ontario Street.

Flash Flood in ERIE, NEW YORK
From 15-AUG-20 19:37:00 to 15-AUG-20 21:00:00 (EST-5)
Location: BUFFALO
Flood cause: Heavy Rain
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Public

Delavan Street was reported flooded with flowing water at Harvard Street.

Flash Flood in ERIE, NEW YORK
From 15-AUG-20 19:45:00 to 15-AUG-20 21:00:00 (EST-5)
Location: BUFFALO
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

A swift water rescue of two people from a car took place on Sycamore Street.