Tropical Storm Rina Dissipates Over Open Atlantic After 45-Knot Peak
Tropical Storm Rina formed in the central Atlantic Ocean on 28 September 2023 and remained a short-lived tropical cyclone through early October. The system reached its peak intensity on 29 September with maximum sustained winds of 45 knots while developing near Tropical Storm Philippe. Rina stayed far from East Asian coastal regions, including China, the Philippines, Japan, and Vietnam, and posed no threat to the western Pacific or South China Sea. The cyclone became a post-tropical remnant low on 1 October 2023 after weakening over the open Atlantic.
From African Wave to Tropical Storm: Rina’s Central Atlantic Genesis
Tropical Storm Rina originated from a tropical wave that moved off the west coast of Africa during 22–23 September 2023. The disturbance crossed the tropical Atlantic and gradually developed within a conducive environment for tropical cyclogenesis. On 28 September at 0600 UTC, the system became a tropical storm near 15.6°N, 44.5°W, with maximum sustained winds of 35 knots and a central pressure of 1005 mb.
The early development of Rina was influenced by surrounding atmospheric conditions and its proximity to another tropical cyclone, Tropical Storm Philippe. Both systems existed in the central Atlantic during the same period, creating a complex forecast environment. Rina’s circulation remained compact, and its structure changed as convection developed and weakened around the center.
Satellite analysis played an important role in monitoring the storm’s organization. Observations from meteorological satellites, Dvorak technique estimates, and other remote sensing tools helped identify the gradual improvement of Rina’s circulation. The storm developed a well-defined low-level circulation, but its overall structure remained limited compared with stronger tropical cyclones.
Rina moved generally north-northwestward across the open Atlantic after formation. Unlike tropical cyclones affecting densely populated coastal regions in the western Pacific, such as the Philippines, southern China, Japan’s island regions, or Vietnam’s coastline, Rina remained far from land throughout its existence and produced no coastal hazards in those areas.
45-Knot Peak Intensity: Rina’s 24-Hour Peak Intensity Phase
Rina reached its peak intensity at 0600 UTC on 29 September 2023, when maximum sustained winds increased to 45 knots, equivalent to approximately 83 km/h. The storm maintained this strength through 30 September, while its minimum central pressure was estimated at 999 mb.
The peak intensity was supported by multiple observations, including subjective and objective satellite estimates as well as scatterometer data. Satellite-based Dvorak analysis classified Rina at T3.0 intensity, while scatterometer measurements detected wind vectors consistent with a 45-knot tropical storm.
Rina’s strengthening phase was limited by increasing wind shear and changes in its convective structure. The storm never acquired the structure typical of stronger cyclones, as thunderstorms became less concentrated near the circulation center. The system gradually lost organization after reaching its highest intensity.
The nearby presence of Tropical Storm Philippe contributed to uncertainty in Rina’s forecast track. Forecast models had difficulty resolving the interaction between the two systems, and this interaction contributed to larger-than-average track forecast errors compared with previous five-year averages.
Despite reaching tropical storm strength, Rina caused no reported damage or fatalities. Its entire period as a tropical cyclone occurred over open waters, preventing direct impacts on populated coastal areas.
Final Advisory: Rina Becomes Post-Tropical Remnant Low
After maintaining tropical storm intensity for approximately one day, Rina weakened as environmental conditions became less favorable. Wind speeds declined from 45 knots as convection decreased and the storm’s circulation became less organized.
By 1 October 2023, Rina weakened into a tropical depression and transitioned into a post-tropical remnant low. The system continued moving across the Atlantic after losing tropical characteristics, with the remaining circulation gradually becoming weaker.
The storm’s short operational period highlighted the challenges of forecasting smaller tropical systems in environments influenced by nearby cyclones. Rina’s track forecasts required adjustments because of its interaction with Philippe, while intensity forecasts depended on continuous satellite observations of convection and circulation changes.
Rina remained entirely outside the western Pacific and South China Sea basin, meaning it had no impacts on East Asian coastal regions monitored by agencies such as China’s meteorological authorities, PAGASA in the Philippines, Japan’s Meteorological Agency, or Vietnam’s national weather services.
According to the official tropical cyclone record, no coastal watches or warnings were issued for Tropical Storm Rina, and no direct fatalities were reported in association with the storm.