The 2003 Atlantic hurricane season was a very active season with tropical cyclogenesis occurring before and after the official bounds of the season—the first such occurrence since the 1970 season. The season produced 21 tropical cyclones, of which 16 developed into named storms; seven of those attained hurricane status, of which three reached major hurricane status. The strongest hurricane of the season was Hurricane Isabel, which reached Category 5 status on the Saffir–Simpson hurricane scale northeast of the Lesser Antilles; Isabel later struck North Carolina as a Category 2 hurricane, causing $5.5 billion in damage (2003 USD) and a total of 51 deaths across the Mid-Atlantic region of the United States.
Although the bounds of the season are typically from June 1 to November 30, the season began early with the formation of Subtropical Storm Ana on April 20, and it ended relatively late on December 11 with the dissipation of Tropical Storm Peter. In early September, Hurricane Fabian struck Bermuda as a Category 3 hurricane, where it was the worst hurricane since 1926; on the island it caused four deaths and $300 million in damage (2003 USD). Hurricane Juan caused considerable destruction to Nova Scotia, particularly Halifax, as a Category 2 hurricane, the first hurricane of significant strength to hit the province since 1893. Additionally, Hurricanes Claudette and Erika struck Texas and Mexico, respectively, as minimal hurricanes. In December, Tropical Storm Odette struck the Dominican Republic, and Tropical Storm Peter formed in the eastern portion of the basin.
Seasonal forecasts
Pre-season outlook
On May 19, prior to the start of the season, NOAA forecasters issued a 55% probability of above normal activity. The forecasters predicted 11–15 tropical storms, 6–9 of those becoming hurricanes, and 2–4 of those hurricanes reaching at least Category 3 strength on the Saffir–Simpson hurricane scale. The above normal activity predicted was due to the likelihood of La Niña developing in the season.
Noted hurricane expert Dr. William M. Gray on April 4 predicted twelve named storms, with eight reaching hurricane strength and three of the eight reaching Category 3 strength. The prediction issued on May 30 was similar, increasing the named storms to fourteen. The synoptic pattern of the season prior to June 1 resembled other previous seasons, with the 1952, 1954, 1964, 1966, and 1998 seasons considered the best analogs for the season. The prediction also included a 68% probability for a hurricane landfall along the United States.
Mid-season outlook
On August 6, Dr. Gray announced he had maintained his previous prediction; with an active start of the season, the rest of the season was forecast to have been only slightly above average, due to an anticipated overall less favorable environment across the Atlantic Ocean. A day later, NOAA released an updated prediction as well, with a 60% probability of above normal activity, with 12–15 named storms, 7–9 hurricanes, and 3–4 major hurricanes expected.
A normal season, as defined by NOAA, has 6–14 tropical storms, 4–8 of which reach hurricane strength, and 1–3 of those reaching Category 3 strength.
Seasonal summary
The official beginning of the season was on June 1, 2003, though Subtropical Storm Ana formed on April 20, well before the start to the season. Starting at the official start of the season, the National Hurricane Center (NHC) began issuing five-day forecasts, extending from the three-day forecasts issued since 1964. Officials conducted tests during the previous two seasons, indicating the new five-day forecasts would be as accurate as the three-day forecasts were 15 years earlier. The tropics were active and well ahead of climatology in the early portion of the season, with the seventh tropical depression forming by the end of July. The season officially ended on November 30, 2003, although tropical storms Odette and Peter developed in early December. The season was one of only six with a storm before and after the official bounds of the season; the others are 1887, 1951, 1953, 1954, 1970 and 2007. When Tropical Storm Peter formed on December 7, the season became the second on record with two December storms. The 235 days between the development of the first storm, Tropical Storm Ana, and the dissipation of the last storm, Peter, made the 2003 season the longest season since 1952.
Overall, the season's activity was reflected with a high cumulative accumulated cyclone energy (ACE) rating of 176. ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, like Fabian and Isabel, have high ACEs. ACE is only calculated for full advisories on tropical systems at or exceeding 34 knots (39 mph (63 km/h) or tropical storm strength. Subtropical cyclones are excluded from the total.
A total of eight tropical cyclones made landfall on Mexico from either the Atlantic or the Pacific Ocean, which was the greatest total since the record of nine in 1971. Seven deaths occurred in Mexico from Atlantic hurricanes. Six tropical cyclones made landfall along the coast of the United States during the season, including two hurricanes. The first, Claudette, struck southeastern Texas in July. In September, Hurricane Isabel hit North Carolina, resulting in 52 fatalities and damage totaling $3.6 billion (2003 USD). It was the costliest disaster in the history of Virginia. Several cyclones impacted Bermuda during the season, most significantly Hurricane Fabian. It was the island's costliest hurricane on record, with a damage total of$300 million. Fabian was also the island's first deadly hurricane since 1926, when it washed away two cars on the causeway between St. George's Parish and St. David's Island. Also in September, Hurricane Juan hit Nova Scotia, becoming the most damaging storm in the history of Halifax, while also causing eight fatalities.
Systems
Tropical Storm Ana
The origins of Ana were from a non-tropical low pressure area that formed about 240 miles (390 km) south-southwest of Bermuda on April 18, from the interaction of an upper-level trough and a surface front. The trough drew moisture from the Caribbean Sea, which caused heavy rainfall in Puerto Rico. On April 19, the non-tropical low began producing sporadic convection, or thunderstorms, as a small inner core formed. The system executed a loop and gradually became dissociated from the front. Early on April 20, the system developed into Subtropical Storm Ana while located about 250 miles (400 km) west of Bermuda. Ana was the earliest subtropical or tropical storm to form in an Atlantic hurricane season since 1978. By the time of its formation, Ana was moving generally eastward while continuing to organize and become more tropical. At 00:00 UTC on April 21, the NHC estimated that Ana transitioned into a tropical storm, with peak winds of 60 mph (95 km/h). This was based on estimates from the Hebert-Poteat technique and data from QuikSCAT. This made Ana the first recorded Atlantic tropical storm in April. Shortly thereafter, it made its closest point of approach to Bermuda, when it passed about 130 miles (210 km) southwest of the island. The storm developed an eye feature, despite the presence of strong wind shear, although the thunderstorms diminished on April 22, and a day later the circulation lost organization. On April 24, Ana merged with an approaching cold front and became an extratropical cyclone. The extratropical storm accelerated east-northeastward before losing its identity within the frontal zone on April 27 southeast of the Azores.
Bermuda issued gale warnings, and later a tropical storm warning. The storm dropped 2.63 inches (67 mm) of precipitation in a six-day period at the Bermuda International Airport. Swells from the storm impacted the coast of Florida. The combination of the swells and an outgoing tide caused a boat to capsize in Jupiter Inlet on April 20; two of its occupants drowned, and the other two were rescued. As an extratropical storm, the remnants of Ana dropped 0.87 inches (22 mm) of precipitation in the city of Ponta Delgada in the Azores. Moisture from the remnants of Ana also produced beneficial rainfall in the United Kingdom.
Tropical Depression Two
A tropical wave moved off the west coast of Africa on June 6. Tracking westward at a low latitude, it encountered favorable environmental conditions, leading to an increase in convection. Early on June 11, it developed into Tropical Depression Two about 830 mi (1,335 km) east-northeast of French Guiana. Its June formation east of the Lesser Antilles was rare. The depression initially had outflow and rainbands. However, the convection quickly diminished and became displaced to the northeast of the center. Late on June 11, the depression degenerated into an open tropical wave about 950 mi (1,530 km) east-southeast of Barbados. Strong wind shear prevented redevelopment, and the remnants later passed through the Windward Islands on June 13.
Tropical Storm Bill
Tropical Storm Bill developed from a tropical wave on June 29 to the north of the Yucatán Peninsula. It slowly organized as it moved northward, and reached a peak of 60 mph (97 km/h) shortly before making landfall 20 mi (30 km) west of Cocodrie, Louisiana. Bill quickly weakened over land, and as it accelerated to the northeast, moisture from the storm, combined with cold air from an approaching cold front, produced an outbreak of 34 tornadoes. Bill became extratropical on July 2, and was absorbed by the cold front later that day.
Upon making landfall on Louisiana, the storm produced a moderate storm surge, causing tidal flooding. In a city in the northeastern portion of the state, the surge breached a levee, which flooded many homes in the town. Moderate winds combined with wet soil knocked down trees, which then hit a few houses and power lines, and left hundreds of thousands without electric power. Further inland, tornadoes from the storm produced localized moderate damage. Throughout its path, Tropical Storm Bill caused around $50 million in damage (2003 USD) and four deaths.
Hurricane Claudette
A well-organized tropical wave tracked quickly through the Lesser Antilles on July 7, producing tropical storm force winds but failing to attain a low-level circulation. After organizing in the Caribbean, it developed into Tropical Storm Claudette to the south of the Dominican Republic on July 8. Its intensity fluctuated over the subsequent days, attaining hurricane status briefly on July 10 before weakening and hitting Puerto Morelos on the Yucatán Peninsula on July 11 as a tropical storm. The storm remained disorganized due to moderate wind shear, though after turning west-northwestward into an area of lighter shear, it re-attained hurricane status on July 15 off the coast of Texas; it intensified quickly and made landfall on Matagorda Island with peak winds of 90 mph (140 km/h). It slowly weakened after moving ashore, tracking across northern Tamaulipas before dissipating in northwestern Chihuahua.
The precursor cyclone caused light damage in the Lesser Antilles, and waves from the hurricane caused an indirect death off of Florida. Widespread flooding and gusty winds destroyed or severely damaged 412 buildings in southeast Texas, with a further 1,346 buildings suffering lighter impact. The hurricane caused locally severe beach erosion along the coast. High winds downed many trees along the coast, causing one direct and one indirect death. Damage was estimated at $180 million (2003 USD).
Hurricane Danny
A large and well-organized tropical wave moved off the coast of Africa on July 9. Cooler waters limited convection as the wave moved northwestward, but thunderstorms increased again on July 13. The system developed into a tropical depression on July 16 about 630 miles (1,015 km) east of Bermuda. The convection organized further, developing banding features, and the depression strengthened into Tropical Storm Danny early on July 17. The storm moved around the western periphery of the subtropical ridge, curving to the northeast over warmer than usual water temperatures for the latitude. After developing a 17 mile (27 km) wide eye, Danny attained hurricane status late on July 18, while located approximately 525 miles (850 km) south of St. John's, Newfoundland and Labrador. The hurricane was embedded within a higher than average surrounding pressure field; as a result, the minimum central pressure was an unusually high 1000 mbar. Danny maintained hurricane status for about 24 hours, until being affected by cooler waters and stronger wind shear. Late on July 19, it weakened into a tropical storm, and fell to tropical depression status the next day. Danny continued around the northern periphery of the ridge, turning to the east and southeast. On July 21, Danny degenerated into a remnant area of low pressure. The low turned southward and southwestward into an area of warmer water temperatures. After executing a small cyclonic loop on July 24, Danny developed deep convection over the center. However, a large area of dry air prevented re-development of the storm. On July 27, the remnant low dissipated about 1,240 miles (2,000 km) east of Bermuda, or about 630 miles (1,015 km) east of where tropical cyclogenesis originally took place.