Strong winds and heavy precipitation in hurricane Melissa enhanced by both human driven climate change and natural variability

Press summary:

• Cyclones similar to Hurricane Melissa are locally up to 14 mm/day (up to  10%) wetter and around 8 km/h windier (up to 10%) today than in the past.
• Hurricane Melissa was driven by exceptional meteorological conditions.
• We ascribe the heavier precipitation and enhanced winds in Hurricane Melissa to human-driven climate change, while natural variability played an important role in modulating the storm’s development and trajectory.

Event description

In October 2025, Hurricane Melissa underwent rapid intensification in the Caribbean Sea, reaching Category 5 strength (sustained winds >175mph / >282km/h) and threatening Jamaica and other Caribbean countries with torrential rainfall, hurricane-force winds, and widespread coastal flooding. A few people have already died in the Caribbean and final casualty figures are expected to rise as the storm’s impacts become clearer. The World Meteorological Organization (WMO) has warned that Hurricane Melissa could be the worst storm to hit Jamaica in the 21st century. The storm has already brought the island to a standstill, with widespread evacuation orders in place. A live update of the hurricane’s progress towards Jamaica is available here. On the Guantanamo coast of Cuba and in parts of Haiti, officials ordered mass evacuations ahead of the storm, with emergency response units mobilized for rescue operations.

The surface pressure anomalies are strongly negative, reaching −25 hPa, to the south of Jamaica. Temperature anomalies are positive over most sea regions, but reach negative values of up to -2 °C over the islands of Jamaica and Hispaniola. Precipitation data reveal extremely high rainfall accumulation, peaking over 400 mm/day near the eyewall. Windspeed data indicate intense sustained daily winds exceeding 80 km/h around Kingston. Our analysis is based on ERA5 data, which assimilates both remotely-sensed and station observations, but values may differ from those observed locally at weather stations.

Climate and data background for the analysis

According to the IPCC WG1 AR6 report, anthropogenic climate change has increased observed precipitation, winds, and storm surge associated with some tropical cyclones. It is likely that there is an increase in the annual global proportion of Category 4 or 5 tropical cyclones and the frequency of rapid intensification events have increased globally  in recent decades. Additionally, it is likely that tropical cyclone translation speed has slowed over the USA since 1900 (IPCC AR6 WGI, Chapter 11). There have been recent observations of slower tropical cyclone translation speeds and higher rainfall totals over the North Atlantic, albeit influenced by substantial natural variability. Projections show low confidence in changes to the overall number of tropical cyclones in the North Atlantic but medium confidence in the likelihood of more intense cyclones with higher winds, precipitation, and storm surge along Mexico, the US Gulf, and Atlantic coasts (IPCC AR6 WGI, Chapter 12). Regarding the economic damages caused by individual extreme events, the report states that formal attribution to anthropogenic climate change has been limited, but climate change could account for a substantial fraction of the damages.  In summary, the IPCC report suggests that climate change has had an impact on hurricane intensity and associated hazards, but the confidence level for these findings varies. The IPCC report also highlights the potential economic damages caused by individual extreme events, and recent studies have used a variety of approaches for attributing these damages to climate change.

Our approach looks for past weather situations similar to those of the current event. For Melissa, we have medium-low confidence in the robustness of our approach, as strong historical hurricanes exist in the observational record, but the scale of this event remains at the upper edge of intensity for the area. Our analysis showed limited sensitivity to the choice of the domain.

ClimaMeter analysis

We analyze here (see Methodology for more details) how events similar to the meteorological conditions leading to Hurricane Melissa have changed in the present (1987–2023) compared to what they would have looked like if they had occurred in the past (1950–1986) in the region [80°W–70°W, 12°N–22°N]. Surface Pressure Changes show that hurricanes similar to Melissa are up to 1 hPa deeper in the present climate. Temperature Changes show that present-day events are up to 0.5 °C warmer near the storm core and over the major Caribbean islands. Precipitation Changes show +14 mm/day (up to 10%) more rainfall, notably over Jamaica. Windspeed Changes show increases of up to 6 km/h, with the strongest increases over sea areas. There is no change in the occurrence frequency of similar past events in October between the two analysis periods. Changes in three urban areas in Jamaica show large increases in both wind speed and precipitation, with the latter reaching close to +20 mm/day.

Finally, we find that sources of natural climate variability, notably the Pacific Decadal Oscillation, El Nino—Southern Oscillation, Atlantic Multidecadal Oscillation, may have affected the trajectory and the development of the cyclones.

Conclusion

Based on the above, we conclude that cyclones similar to Hurricane Melissa are around 0.5 °C warmer, up to 14 mm/day (10%) wetter, and up to 8 km/h (up to 10% windier) in the present compared to the past. This contributes to more extreme rainfall and flooding risks, especially in urban areas like Kingston. We interpret the increased precipitation and stronger winds associated with Hurricane Melissa as being amplified by human-driven climate change, while natural variability played an important role in modulating the storm’s development and trajectory.