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Overview

A potent upper-level trough swept east across the Upper Great Lakes, extending a cold front east through the area. Thunderstorms developed along a pre-frontal trough ahead of the cold front Thursday afternoon across portions of Michigan and Indiana, and continued southeastward across northern OH and Northwest Pennsylvania into the evening hours. The environment was favorable for severe weather, particularly damaging wind gusts and large hail, and was characterized by steep mid-level lapse rates greater than 7 C/km, strong instability greater than 2000 J/kg, and modest bulk shear of 35 to 40 knots. Significant hail (2 inches in diameter in Westlake, OH and Corry, PA) and wind gusts (81 mph wind gust at Fairport Harbor, OH) were reported during the course of the event, resulting in numerous storm damage reports across the area. Several storms exhibited strong rotation on radar, resulting in 4 tornado warnings during the course of the event. Torrential rainfall also accompanied severe thunderstorms, leading to pockets of rate-driven flash flooding, especially within the Cleveland Metro area.

Image
GOES-16 "sandwich" satellite product (visible and infrared) with the Geostationary Lightning Mapper (GLM) flash extent density overlaid. This loop is from 2 PM to 11 PM on July 20, 2023.
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