The 1966 Atlantic hurricane season saw the Weather Bureau office in Miami, Florida, be designated as the National Hurricane Center (NHC) and assume responsibility of tropical cyclone forecasting in the basin. The season officially began on June 1, and lasted until November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. It was an above-average season in terms of tropical storms, with a total of 15. The first system, Hurricane Alma, developed over eastern Nicaragua on June 4 and became a rare major hurricane in the month of June. Alma brought severe flooding to Honduras and later to Cuba, but caused relatively minor impact in the Southeastern United States. Alma resulted in 90 deaths and about $210 million (1966 USD) in damage.
The unnamed June tropical storm and Becky, Celia, Dorothy, and Ella all resulted in little to no impact on land. The next system, Hurricane Faith, developed near Cape Verde on August 21. It tracked westward across the Atlantic Ocean until north of Hispaniola. After paralleling the East Coast of the United States, Faith moved northeastward across the open Atlantic and later became extratropical on September 4. Although it never made landfall, Faith and its remnants generated rough seas that resulted in four deaths, with one over the open Atlantic and the other four offshore Denmark. The two next tropical storms – Greta and Hallie – caused negligible impact.
The strongest tropical cyclone of the season was Hurricane Inez, a powerful Category 5 hurricane that devastated a large majority of the Caribbean, the Florida Keys, and parts of Mexico. Throughout its path, the storm caused about $222.5 million in damage and more than 1,000 deaths. Following Inez, the other cyclones reaching at least tropical storm intensity, Judith, Kendra, Lois, and two unnamed systems in November did not result in significant impacts on land. The final system, an unnamed tropical storm, degenerated into a trough over the western Atlantic on November 26.
Season summary
The Atlantic hurricane season officially began on June 1. During the year, the Miami, Florida, Weather Bureau office was re-designated the National Hurricane Center. It was an above average season in which fifteen tropical storms formed, compared with the 1966–2009 average of 11.3 named storms. Seven of these reached hurricane status, slightly above of the 1966–2009 average of 6.2, and three of those reached major hurricane status, with the 1950–2000 mean being 2.3. In all, three hurricanes and one tropical storm made landfall in 1966. Also, collectively, the season's storms caused at least 1,094 fatalities and about $432.6 million (1966 USD) in damage.
The season officially ended on November 30.
The first storm, Hurricane Alma, developed over eastern Nicaragua on June 4. Alma crossed the Caribbean and struck Cuba. The storm made another landfall in Florida as a hurricane on June 9. This marked the earliest United States hurricane landfall since a hurricane in May and June of 1825. Alma continued northeastward across the Southeastern United States until becoming extratropical offshore Virginia on June 13. Later that month, another tropical depression developed. The month of July was highly active, with four named storms – Becky, Celia, Dorothy, and Ella. Additionally, a tropical depression developed in the Gulf of Mexico. However, tropical cyclogenesis then halted for more than three weeks, until Hurricane Faith developed on August 21. On average, three or four named storms form in August.
Four tropical cyclones developed in September, including tropical storms Greta, Hallie and Judith, as well as Hurricane Inez. Peaking as a Category 5 hurricane on the Saffir–Simpson hurricane wind scale with winds of , Inez was the strongest tropical cyclone of the season. Although Inez persisted into October, no other system developed that month. Two named storms usually form in October. The final formally named storm, Hurricane Lois, existed from November 4 to November 11.
The season's activity was reflected with an accumulated cyclone energy (ACE) rating of 145. 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, have high ACEs. It is only calculated for full advisories on tropical systems at or exceeding , which is tropical storm strength.
Systems
Hurricane Alma
A westward-moving tropical wave crossed the Caribbean Sea and reached Central America in early June. Land interaction initially slowed development. However, after the wave turned northward and reemerged into the Caribbean, it quickly organized into a tropical depression at 12:00 UTC on June 5. While moving through Honduras, the precursor system dropped heavy rainfall that killed at least 73 people in the city of San Rafael. Offshore northern Honduras, the system produced heavy rainfall on Swan Island. The depression moved north-northeastward and intensified into Tropical Storm Alma around 00:00 UTC on June 6, about 18 hours before becoming a hurricane. After strengthening into a Category 2 hurricane on June 8, Alma made two landfalls in Cuba, first on Isla de la Juventud with winds of and then near Guanimar, Artemisa Province, at a slightly stronger intensity. Havana observed wind gusts up to . The hurricane caused heavy crop damage and water shortages. Over 1,000 houses were destroyed, and damage was estimated at $200 million. The storm killed 12 people in the country.
After emerging into the Straights of Florida around 13:00 UTC on June 8, Alma continued to intensify and reached major hurricane intensity five hours later. The storm then peaked as a Category 3 hurricane with maximum sustained winds of and a minimum barometric pressure of as it passed between Dry Tortugas and Key West, Florida. The latter reported power outages and flooding. Alma dropped heavy rainfall and produced winds across most of Florida, which damaged crops and caused scattered power outages. The cyclone weakened to a Category 1 hurricane before moving ashore near St. Marks, Florida, late on June 9 with winds of . This was the earliest date of landfall in the United States since 1825. Damage in Florida was estimated at $10 million, and there were six deaths in the state. Alma crossed southeastern Georgia as a tropical storm, damaging a few houses and causing light damage. The storm re-intensified into a hurricane over the western Atlantic Ocean around 12:00 UTC on June 11, and its outer rainbands dropped heavy precipitation in Wilmington, North Carolina. Alma encountered colder water temperatures and weakened back to tropical storm intensity late on the following day, shortly before transitioning into an extratropical cyclone east of the Outer Banks. The remnant extratropical storm was absorbed by a frontal boundary just offshore Massachusetts on June 14.
June tropical storm
A strong tropical wave developed into a tropical depression in the northwestern Caribbean Sea on June 28. The depression moved slowly northward and although it remained poorly defined throughout its duration, the system intensified into a tropical storm early the following day. Also despite being described as poorly defined, the wind field was well organized, especially in the northeastern quadrant. Around 14:00 UTC on June 29, the storm made landfall on Cuba's south coast just west of the modern-day border of Artemisa and Mayabeque provinces with winds of . The cyclone emerged into the Straights of Florida several hours later. Early on June 30, the system peaked with sustained winds of and a minimum pressure of while approaching the Florida Keys. Continuing northward, the storm passed just west of the Tampa Bay area on July 1 before striking Cedar Key at 22:00 UTC with winds of . The system curved northeastward and weakened to a tropical depression over southern Georgia at 06:00 UTC on July 2, about 12 hours before dissipating.
The storm spawned two tornadoes, one of which destroyed two aircraft at Palm Beach International Airport; the other touched down in Vero Beach and caused minimal effects. The storm dropped heavy rainfall in some areas of Florida, with a peak total of in Everglade City and Jacksonville. The precipitation in Jacksonville resulted in $50,000 in damage to roadways. Additionally, the cyclone brought "beneficial rains" to South Carolina.
Hurricane Becky
In late June, a weakening frontal boundary and an upper-level trough traversed the western Atlantic. A significant convective flare occurred along the tail-end of the frontal system between the Bahamas and Bermuda on June 27. The frontal system also began interacting with the northern part of a westward-moving tropical wave over the Caribbean. After a well-defined center developed on June 30, the system became a subtropical depression near Bermuda at 12:00 UTC. Six hours later, the cyclone intensified into a subtropical storm. Based on satellite imagery, the system transitioned into a tropical storm around 12:00 UTC on July 1. Becky continued to intensify while heading northeastward under an upper-level trough. The storm reached hurricane status by midday on July 2, six hours before peaking with maximum sustained winds of and a minimum barometric pressure of . However, Becky soon began weakening and losing tropical characteristics, becoming an extratropical cyclone early on July 3. A cold low then caused the remnants of Becky to turn northwest toward Atlantic Canada, before being absorbed by another extratropical system to the north several hours later.
Hurricane Celia
A tropical wave spawned a tropical depression west of the Leeward Islands at 00:00 UTC on July 13. Six hours later, ship reports indicated that the depression strengthened into Tropical Storm Celia. However, because satellite imagery showed only a weak swirl with convection sheared well to the southeast, Celia degenerated back to a tropical wave early on July 14 north of Puerto Rico while moving westward. While nearing the central Bahamas late on July 18, the remnants of Celia regenerated into a tropical depression after regaining a low-level circulation. That day, Celia turned northward back into the open Atlantic. Observations from a ship indicate that Celia re-strengthened into a tropical storm early on July 20 as it accelerated northeastward ahead of a frontal boundary. The storm intensified significantly throughout the day, reaching hurricane status at 18:00 UTC. Celia then peaked with sustained winds of and a minimum pressure of . The cyclone soon began to weaken, falling to tropical storm intensity at 06:00 UTC on July 21. Six hours later, Celia transitioned into an extratropical cyclone, which struck eastern Nova Scotia late on July 21 and then dissipated over Labrador on the following day.
Only light rainfall was observed in Atlantic Canada and Quebec, with a peak total of in Nova Scotia. Portions of Newfoundland experienced wind gusts up to .
Hurricane Dorothy
In late July, a low-level disturbance situated over the central Atlantic Ocean encountered a vigorous shortwave trough and developed into a surface low-pressure area on July 21. Initially, the depression had extratropical features and lacked tropical characteristics, such as a warm core and a well-developed central dense overcast. A weather ship in the area indicated an influx of baroclinity, suggesting that Dorothy derived its energy through non-tropical processes. Around 06:00 UTC on July 23, the depression strengthened into Tropical Storm Dorothy. Thereafter, it moved in quasi-stationary motion to the northwest and continued to intensify, reaching hurricane status late on July 24.