On June 20, the first tropical depression of the season formed in the extreme eastern Caribbean Sea. Given favorable conditions for strengthening, the depression became Tropical Storm Arthur overnight. After reaching 50 mph winds on the evening of June 21, Arthur briefly weakened before re-strengthening to become the season's first hurricane on June 23, and made landfall in eastern Haiti at its peak intensity of 80 mph winds later that day. As Arthur slowed to a crawl over Hispaniola, it rapidly weakened, and dissipated on June 24.
Arthur was the deadliest, and perhaps most notable, storm of the season. Arthur was a weak hurricane of only Category 1 intensity, so the storm's 80 mph winds were not the prime factor of its effects on Hispaniola. Instead, Arthur's slow movement allowed torrential rainfall to build up quickly, causing catastrophic flooding with little help from the mere 5 to 6-foot storm surge. Over 1,200 deaths were reported from Arthur, mostly from the flooding in Haiti. Arthur also managed to do this as a weak and small hurricane. Had Arthur been a large major hurricane, experts predict that Arthur would have caused over 3,000 deaths. As fate would have it, the next year saw Hurricane Heffer, another catastrophic Haitian hurricane that was deadlier, stronger, larger, and more destructive than Arthur. Arthur caused over $400 million (1984USD) in damage, primarily in Haiti.
Tropical Storm Bertha
A weak tropical storm that brushed Bermuda. Brought some showers to Bermuda and minor flooding. It dissipated off the coast of Newfoundland.