After reaching Category 2 status on the Saffir–Simpson scale, Tomas quickly weakened to a tropical storm in the central Caribbean Sea, due to strong wind shear and dry air.

[2][3] During this time the wave's structure retained a vigorous appearance;[1] the western portion contained scattered convection, with strong thunderstorms, as well as a broad area of rotating winds.

[3] On October 27, when the system was about 1,200 miles (1,900 km) east-southeast of the Windward Islands, the National Hurricane Center (NHC) noted favorable atmospheric conditions for tropical cyclogenesis, namely light wind shear.

[1][5] A Hurricane Hunters aircraft investigating the disturbance on October 29 observed a developing circulation with tropical storm-force winds at sea level.

[1][7] On its inception, Tomas turned toward the northwest and decelerated[1] within a region of low wind shear and high tropical moisture—two of the prime prerequisites of rapid intensification.

A misalignment between the cyclone's low- and upper-level circulations impeded this strengthening potential, however, and at that time the NHC did not expect Tomas to attain hurricane status until 36 to 48 hours later.

[1][8] Despite the prior forecasts of moderated strengthening, Tomas' winds sharply increased to 60 mph (97 km/h) by late October 29;[9] moreover, the outflow aloft became well established in all quadrants as the convection consolidated into a prominent rain band.

[13] Tomas diminished to a tropical storm early on November 1, when the strongest thunderstorms became dislocated from the low-level wind vortex by more than 115 mi (185 km).

[1][15] Although the upper wind regime relaxed into the next day, with an area of deep convection briefly reblossoming near Tomas' center,[15] the shear appeared to have already taken its toll on the storm.

With an increasingly diffuse and elongated structure, Tomas further weakened to a tropical depression at 00:00 UTC, November 3, about 325 miles (523 km) southeast of Kingston, Jamaica.

A Hurricane Hunters mission to determine whether Tomas retained its status as a tropical cyclone found that the mean low-level circulation had reformed to the northeast of the previous center.

Tomas reattained tropical storm strength late on November 3,[17][18] and although the low- and mid-level centers were initially nonaligned, slow restrengthening ensued into the next day.

[21] While turning northeastward into the Windward Passage, Tomas regained hurricane status around 0600 UTC on November 5, just 36 miles (58 km) west-southwest of the western tip of Haiti.

Due to its proximity to land, the convection became disrupted near the center;[23] Tomas reweakened to a tropical storm near the Turks and Caicos Islands during a spell of moderate shear on November 6.

[1] After moving through that island nation, Tomas briefly became a hurricane for a final time before hostile wind shear from the nearby trough fully began to take effect.

It turned sharply eastward before curving northward, accelerated by a broad cyclonic steering flow over the western Atlantic the next couple of days.

Following the west-southwesterly motion of the storm, swells generated by Tomas produced breaking waves on coastal sections of the ABC islands during the morning of November 1.

[31] In Haiti, the country which was devastated earlier in the year from a deadly January 12 earthquake, government officials began preparing for possible impact from Tomas by October 30.

[28] As Tomas passed 20 miles (32 km) to the south of Barbados, it produced a wind gust of 63 mph (101 km/h), which damaged homes and power lines on the island.

[42] The majority of the rain fell overnight in a heavy downpour, accompanied by a severe thunderstorm that triggered large-scale power, TV and radio outages.

Parts of Bonaire experienced heavy but brief periods of rain, with a maximum of 3 inches (76 mm) at Flamingo International Airport, causing localized flooding of property.

[51] While passing the Windward Islands into the Caribbean Sea, Tomas produced strong winds and heavy rainfall on Isla Aves, located off the northern coast of Venezuela.

[57] As the outer bands of Hurricane Tomas began to impact Cuba, Aero Caribbean Flight 883, an ATR-72-212 aircraft, crashed near the town of Guasimal in Sancti Spíritus province.

Although the plane was the last to leave the airport in Santiago de Cuba before it closed due to Tomas, it is unknown what role, if any, the storm played in the crash.