Which 1994 tropical storm formed on June 30 and proved to be the costliest of that Atlantic hurricane season?
Timeline of the 1994 Atlantic hurricane season: The 1994 Atlantic hurricane season was a below-average Atlantic hurricane season that produced seven named tropical cyclones. Timeline of the 1994 Atlantic hurricane season:  The first named storm, Tropical Storm Alberto, formed on June 30. Tropical Storm Alberto (1994): Tropical Storm Alberto was the costliest storm of the 1994 Atlantic hurricane season.
Tropical Storm Alberto