Tropical Storm Philippe Drenched Leeward Islands With Flooding Rain
Tropical Storm Philippe formed on 23 September 2023 over the eastern Atlantic and dissipated on 6 October after moving through the tropical Atlantic and western Atlantic. The cyclone reached peak intensity on 25 September with maximum sustained winds of 50 kt and a minimum central pressure of 998 hPa. Philippe passed near the Leeward Islands in early October, bringing heavy rainfall that affected Antigua, Barbuda, and nearby islands. The system lost tropical characteristics and merged with a larger non-tropical low over the Atlantic after maintaining tropical storm strength through its final advisory period.
From African Wave to Named Storm: Philippe’s First Days Over the Atlantic
Philippe developed from a tropical wave that moved off the west coast of Africa on 20 September 2023. The disturbance entered the eastern Atlantic with thunderstorms that gradually became organized as it traveled westward south of a subtropical ridge near the Cabo Verde Islands. Satellite imagery and meteorological observations showed increasing circulation development, and a tropical depression formed at 0600 UTC on 23 September, approximately 1,350 nautical miles east of Barbados.
Twelve hours after formation, the depression strengthened into Tropical Storm Philippe. The cyclone moved westward to west-northwestward during its early stage while atmospheric conditions allowed its circulation to become better defined. Warm ocean waters, adequate moisture, and limited early wind shear helped Philippe intensify from a depression with 30 kt winds into a tropical storm with 45 kt winds by 24 September.
Philippe continued strengthening on 25 September and reached its maximum intensity at 0600 UTC. The storm was located near 17.1°N, 43.8°W, with maximum sustained winds of 50 kt and a minimum central pressure of 998 hPa. This peak marked the strongest point in Philippe’s lifecycle before changes in the surrounding atmosphere began weakening its structure.
After reaching peak intensity, Philippe encountered stronger westerly vertical wind shear. The storm’s circulation became separated from its deepest thunderstorms, leaving the center exposed at times on satellite imagery. The cyclone weakened to 45 kt on 26 September and later maintained tropical storm status while moving across the central Atlantic.
Wind Shear Disrupted Philippe’s Core as the Storm Drifted for Days
Philippe’s movement became slower and less direct after 25 September as steering patterns changed across the Atlantic. The weakening influence of the mid-level ridge north of the storm altered its track, while the cyclone’s shallow circulation responded to smaller-scale atmospheric changes. From 27 to 29 September, Philippe moved slowly and experienced periods of irregular motion.
Although Philippe remained over warm sea surface temperatures, stronger upper-level winds prevented the storm from rebuilding a compact inner core. The strongest thunderstorms frequently developed east of the center rather than directly around it. This asymmetric structure allowed the cyclone to remain a tropical storm while limiting further intensification.
By 30 September, Philippe began moving toward the northern Leeward Islands region. The storm briefly strengthened again, reaching 50 kt winds on 1 October while located east of the Caribbean islands. However, the circulation remained affected by wind shear, and the strongest impacts came from rainfall rather than concentrated destructive winds.
The National Hurricane Center issued regular advisories during this period, including warnings and forecasts describing Philippe’s track toward the northeastern Caribbean. The storm maintained a tropical storm classification as it approached the islands, with winds remaining below hurricane strength.
Rainbands Soaked the Leeward Islands Even as Philippe’s Winds Remained Modest
Philippe’s main impact across the Leeward Islands came from rainfall. As the cyclone passed near the region in early October, its rainbands spread moisture across Antigua, Barbuda, and surrounding islands. Forecast information from the National Hurricane Center highlighted rainfall totals of 4 to 6 inches in parts of Antigua and Barbuda, with 2 to 4 inches across other areas of the Leeward Islands.
The rainfall produced periods of flooding, especially in areas with vulnerable drainage systems and steep terrain. The storm’s uneven structure meant that the heaviest precipitation was not concentrated directly around the center, allowing outer rainbands to deliver significant weather away from the core circulation.
Philippe’s wind impacts remained limited compared with stronger tropical cyclones. The system reached the islands as a disorganized tropical storm, but its moisture field created hazardous conditions through heavy downpours and runoff. Local emergency services monitored rainfall conditions as communities prepared for flooding threats.
The cyclone demonstrated how a tropical storm with moderate winds can still create serious weather impacts. Philippe’s rainfall pattern was linked to its large circulation, slow movement near the region, and continued tropical moisture transport.
Philippe Became Post-Tropical and Merged With a Larger Low Over the Atlantic
After affecting the Leeward Islands, Philippe turned northward over the western Atlantic. The storm gradually lost tropical organization as it interacted with a larger non-tropical weather system. Thunderstorm activity became increasingly separated from the center, and the cyclone transitioned away from a warm-core tropical structure.
During its final advisory period, Philippe remained a tropical storm with maximum sustained winds of 45 kt, equivalent to about 50 mph. The storm’s central pressure was analyzed at 1003 hPa, and its final tropical storm position was near 30.7°N, 64.6°W before merging with a larger low-pressure system.
Philippe completed a 13-day tropical cyclone lifecycle from formation on 23 September to dissipation on 6 October 2023. The storm reached its peak intensity at 17.1°N, 43.8°W on 25 September with 50 kt winds and a 998 hPa central pressure, then continued across the Atlantic before becoming absorbed by a non-tropical low.