May 30
edit1959: Tropical Storm Arlene made landfall near Lafayette, Louisiana, bringing more than 10 inches (25 cm) of rain to parts of the northern Gulf Coast of the United States.
1998: After a supercell spawned an F4 tornado that nearly wiped out the town of Spencer, South Dakota, the storms organized into a destructive derecho that tracked over 1,000 miles (1,609 km) across the southern Great Lakes region of the United States and Canada.