Two clusters of severe thunderstorms, one over northeastern Minnesota, and the other just north of the Twin Cities, produced numerous reports of large hail during the afternoon and evening of Friday July 26th.
The severe storms formed along a weak cold front sweeping across Minnesota. Ahead of the cold front, warm and unstable air surged northward throughout the state. As thunderstorms formed, strong winds aloft created enough wind shear to allow the cells to isolate themselves and begin rotating, which enabled these "supercell" thunderstorms to become unusually strong and damaging.
The storms produced half dollar-sized hail near Cook and Eveleth, and widespread ping pong ball to tennis ball-sized hail from St. Cloud into the northern suburbs of the Twin Cities. The largest hailstone reported was grapefruit-sized, or 4 inches in diameter, near Clear Lake in Sherburne County.
The storms in northeastern Minnesota eventually consolidated into a line and produced wind damage to trees and powerlines near Tower, Brimson, and Two Harbors. In the Boundary Waters Canoe Area Wilderness, a group of nine Girl Scouts from the Chicago area had to be rescued and evacuated after lightning struck their camp on Knife Lake, causing minor injuries.
The severe thunderstorms near the Twin Cities were highly visible from all directions, and produced frequent and vivid lightning as the sun went down. Area residents gathered on porches and sidewalks to take in the remarkable display.
Below are hail reports collected from the National Weather Service office in Chanhassen.
PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 839 AM CDT SAT JUL 27 2019 ..HAIL REPORTS FROM FRIDAY AND EARLY SATURDAY LOCATION SIZE TIME/DATE PROVIDER 5 NE CLEAR LAKE 4.00 IN 0545 PM 07/26 STORM CHASER SHOREVIEW 3.00 IN 0820 PM 07/26 PUBLIC ST. CLOUD 2.50 IN 0527 PM 07/26 PUBLIC CLEAR LAKE 2.50 IN 0610 PM 07/26 PUBLIC SAUK RAPIDS 2.50 IN 0522 PM 07/26 PUBLIC 1 ENE ST. CLOUD 2.00 IN 0540 PM 07/26 ST. CLOUD 2.00 IN 0527 PM 07/26 PUBLIC 4 S ORROCK 2.00 IN 0717 PM 07/26 PUBLIC SHOREVIEW 2.00 IN 0820 PM 07/26 PUBLIC 2 NNE MOUNDS VIEW 2.00 IN 0828 PM 07/26 TRAINED SPOTTER CIRCLE PINES 2.00 IN 0813 PM 07/26 PUBLIC OTSEGO 1.75 IN 0650 PM 07/26 PUBLIC 4 SW ZIMMERMAN 1.75 IN 0728 PM 07/26 TRAINED SPOTTER 2 NNE MOUNDS VIEW 1.75 IN 0816 PM 07/26 TRAINED SPOTTER WHITE BEAR LAKE 1.50 IN 0830 PM 07/26 PUBLIC NORTH OAKS 1.50 IN 0821 PM 07/26 PUBLIC 2 NW ROGERS 1.50 IN 0655 PM 07/26 STORM CHASER SAUK RAPIDS 1.50 IN 0537 PM 07/26 TRAINED SPOTTER RAMSEY 1.50 IN 0715 PM 07/26 PUBLIC OTSEGO 1.25 IN 0648 PM 07/26 PUBLIC SARTELL 1.25 IN 0518 PM 07/26 PUBLIC 4 SSE ZIMMERMAN 1.25 IN 0738 PM 07/26 TRAINED SPOTTER 4 NNW OTSEGO 1.25 IN 0730 PM 07/26 TRAINED SPOTTER 2 ESE NORTH OAKS 1.25 IN 0840 PM 07/26 TRAINED SPOTTER DAYTON 1.25 IN 0715 PM 07/26 PUBLIC 2 NE MOUNDS VIEW 1.25 IN 0827 PM 07/26 TRAINED SPOTTER ---TRUNCATED---
Modified July 29, 2019