Unfolding Event: Hurricane Dorian
Hurricane Dorian is the fourth named system of the 2019 season. It formed as a tropical wave in the Atlantic and developed tropical storm characteristics on August 24. Continuously strengthening, the system passed Puerto Rico on the east, hitting the US Virgin Islands with only light impact. Avoiding the interaction with Puerto Rico’s mountainous landmass allowed the system to further organise into a hurricane on August 28.
The system is currently a category 2 hurricane and expected to reach major hurricane status later today. The future track will take Dorian in north-westerly direction with a bend to the west during the weekend. This path will take Dorian over 29-30°C warm waters which will allow the system to further strengthen. Wind shear is low for the next two days, which supports intensification, and will moderately increase when Dorian approaches land.
Dorian’s future track is determined by the interaction of two large-scale weather effects. A developing Bermuda high is responsible for the bending from the north-westerly track towards Florida. Simultaneously, a frontal system is approaching from the west over the US mainland, which has the potential of slowing down Dorian’s forward movement and eventually deflecting the system to the north. The exact timing of both weather phenomena will decide where Dorian finally will make landfall, how fast the system will be at this time, and whether a slowing down might reduce its strength at landfall, because even though the ocean waters are warm at the surface, the total heat content below Dorian’s path is only moderately high and a stalling of the storm would upwell colder water.
The most likely scenario for Dorian today is a hit on the central part of Florida’s East Coast as a Cat 4 hurricane. However, the best forecasting models still show ensemble member solutions that range from south of Miami to close to the Georgia border and the historic (last 5 years) uncertainty in the track forecasts of the US National Hurricane Center four days out is about 300 km. Hence any ‘single line’ forecast tracks should be taken with the necessary scepticism. Further, as mentioned above, the ultimate track that Dorian will take has an impact on its strength at landfall. Due to this uncertainty, Solidum believes that it is too early to give useful forecasts of industry loss ranges and portfolio impacts. However, Dorian is certainly an event with the potential of generating noticeable losses in Florida.
The portfolio management team remains at your disposal for any additional questions.
The Solidum Management Team