In response and some fear to the storm's projected path into the Gulf of Mexico, prices for crude oil rose on the New York Mercantile Exchange at branch offices in London. Natural gas prices rose considerably in New York Mercantile Exchange electronic trading on August 2. Anticipation of a threat to supply by a potential Hurricane Chris coupled with high demand during an ongoing heat wave are cited as reasons for the price move. Also, numerous oil rigs were closed and ditched in response to the storm for the fear of Hurricane Katrina a year earlier. On August 2 approximately 600 tourists evacuated the Puerto Rican islands of Vieques and Culebra as tropical storm warnings had been issued. Cruise lines such as Royal Caribbean re-routed their ships to avoid the storm. In Puerto Rico, rainfall from the storm caused the Fajardo River to overflow its banks. The overflown waters temporarily closed a highway in the northeastern portion of the island. Rainfall reached up to 2 inches (50 mm) across portions of Hispaniola, the Turks and Caicos, the Bahamas, and eastern Cuba, and reached 4 inches (100 mm) in some mountainous areas.
A tropical system off the coast of Africa, which the National Hurricane Center was monitoring for several days, was upgraded to tropical depression status on August 21 and designated as Tropical Depression Four. Consequently, a tropical storm warning was immediately issued for the Cape Verde islands, as the system threatened to pass over or near the southern part of the archipelago. However, the system failed to strengthen into a tropical storm before passing the chain of islands, and the warning was discontinued the following morning.
The depression was upgraded to a tropical storm and was named Debby late on August 22. While it had been expected to strengthen into a hurricane, Debby weakened into a tropical depression on August 26. It continued to the north and lost tropical characteristics on August 27.
At 3:15 p.m. EDT (1915 UTC) on 24 August, a reconnaissance flight determined that a tropical wave passing through the Windward Islands had developed a closed tropical circulation, and advisories were commenced on Tropical Depression Five. By 5 p.m. EDT (2100 UTC) on 25 August, a second flight had found sustained tropical-storm force winds, and the system was named Ernesto. Ernesto became a hurricane on the morning of 27 August just south of Haiti, before it was downgraded back to a tropical storm in the afternoon. The storm caused 2 deaths in Haiti due to rainfall.
Ernesto made landfall near Guantanamo Bay, Cuba, early in the morning on 28 August. At one point the storm was predicted to become a major hurricane in the Gulf of Mexico and threaten parts of the Gulf Coast, a grim possibility in light of the one-year anniversary of Hurricane Katrina's landfall. However, Ernesto moved much farther east than anticipated, and made landfall as a tropical storm on the southern tip of Florida on 29 August. Two people died in Florida in road traffic accidents attributed to the weather conditions, as the cyclone slowly moved northward across the southern half of the peninsula. Ernesto restrengthened into a tropical storm as it emerged from land near Cape Canaveral, and was just below hurricane strength when it made landfall again in North Carolina on 31 August.
Damage in Virginia totaled to $104 million (2006 USD)
Tropical Depression Six formed from an area of low pressure midway between Africa and the Lesser Antilles on 3 September. Initial strengthening of the depression was slow due to shearing wind conditions. Despite the moderate to high wind shear, it strengthened enough to become Tropical Storm Florence on the morning of 5 September. After becoming a tropical storm, Florence's wind field began to expand greatly; at one point tropical storm-force winds extended outward up to 405 miles from the center. With a disorganized structure and multiple circulation centers, Florence remained a weak tropical storm for several days, even after external conditions became favorable for strengthening. Around the evening of 8 September it resolved to a single center and steady strengthening resumed - "science had prevailed", as one forecaster remarked. On the morning of 10 September, Florence reached hurricane strength. Large swells, rip tide, and undertow were reported on Bermuda, the Leeward Islands, the Virgin Islands, and Hispaniola. Florence soon reached its peak as a Category 1 hurricane very near Bermuda, and became extratropical on 12 September, while still a hurricane.
As Hurricane Florence moved norhtwestward, an area of low-pressure with scattered thunderstorm activity slowly became more organized while northeast of the Lesser Antilles. On the evening of September 10, it developed a closed circulation and was called Tropical Depression Seven. It continued to strengthen, and was then named Tropical Storm Gordon on September 11 and Hurricane Gordon late on September 12. Gordon attained Category 2 status on the evening of September 13, and was further upgraded to Category 3 status that same night, making it the first major hurricane of the season.
Around September 16 it was nearly froze for some time in the mid-Atlantic about 1000 miles east of Bermuda, and became a weak hurricane. However, it subsequently accelerated eastwards and strengthened to become category 2. On 19 September hurricane warnings were issued for the Azores, as the predicted path passed through the center of that archipelago. It became extratropical on September 20 after passing through Azorean waters, but the remnants side-swiped north-western Spain and then moved rapidly north towards Ireland and the west of Britain on September 21. By the morning of September 22, it had been absorbed into a large Atlantic low to the west of Ireland.
On September 10, an area of clustered thunderstorms began to move off the western African coast. It quickly became stronger and organized itself to become Tropical Depression Eight. Continuing to organize, it reached tropical storm strength on September 13, becoming a hurricane on September 16 and a major hurricane (Category 3 or higher on the Saffir-Simpson hurricane scale) on September 17. Helene moved generally west-northwestward before commencing a northeasterly turn. Large currents from Helene lashed Bermuda. The hurricane then became an extratropical storm on September 24 and died shortly after.
An area of low pressure in mid-Atlantic generated active thunderstorms for several days and eventually organized into Tropical Depression Nine on 27 September and a tropical storm by 28 September. By that time it was about east-southeast of Bermuda. It became a hurricane on 30 September, and passed about east of Bermuda before swinging northwards towards Newfoundland. As it was still a strong tropical storm near the Avalon Peninsula, tropical storm warnings were issued on 2 October due to the potential for high winds. Isaac passed to the southeast of Cape Race late that afternoon. The Canadian Hurricane Centre reports that if Isaac had tracked just 50 to 100 km (30 to 60 miles) further north than it did, the St. John's area would have experienced much higher winds than the peak gust of it received.
At its closest approach to the Avalon Peninsula, Isaac was still tropical, and had maximum sustained winds of and a minimum central pressure of 993 mbar. Strongest winds on land in Newfoundland were reported at Cape Race, where a maximum gust to with a sustained wind of was recorded. At Cape Pine, a peak wind was reported at . However, due to Isaac's small size and fast forward speed, winds were lighter over most of the Avalon Peninsula.
Rainfall from Isaac was not reported to be higher than in most areas due to Isaac's speed and decreasing amount of moisture. The highest measured amount was at Cape Race, while Cape Pine reported and St. John's reported less than .
strength.