Hurricane Dorian continues on a northwestward trajectory as it moves away from Puerto Rico. Dorian has begun to encounter a considerably moister environment; thus, dry air entrainment into the storm’s circulation will become less of a problem with time. As of the 5pm ET advisory, Hurricane Dorian remains at category 1 status, but a steady or even rapid change in strength should occur over the next 24 hours. An upper-level low pressure system to Dorian’s west-northwest will impinge some southeasterly shear on Dorian’s left side, but as the upper low continues on a westward path, wind shear will lessen in Dorian’s vicinity within the next 24 hours. Sea surface temperatures are well-above the necessary 26.5°C threshold to support tropical development and intensification. With everything considered, we feel confident that Dorian will remain in an environment that will allow continued strengthening. Of course, there’s always the possibility that some additional shear or dry air could become an issue in a few days, but there’s nothing currently that we see as being an issue for the storm.
Right now, we need to figure out where Dorian will go. Looking at climatology, the majority of tropical systems that have previously been within the vicinity of Dorian’s location eventually approached Florida but actually made landfall in the Carolinas. A handful of the storms did go into the Gulf of Mexico, and only a few made landfall in Florida. Although climatology can be extremely useful, one does have to be careful when trying to use it to predict future events. Each storm is different.
With that said, I suspect that the more eastward trend in the model guidance is closer to what will occur, but the current scenario could be worst from both a flooding and wind damage perspective. The strength of the Bermuda ridge will remain crucial as to just how far west Dorian makes it before making a northward turn. This actually brings back flashbacks of Hurricane Matthew, because we really struggled to pin down when that turn would occur. Matthew luckily turned before significantly impacting Florida, but as most remember, the storm eventually produced copious amounts of rainfall in parts of the Carolinas.
The latest GFS and European model currently project Dorian to make landfall in south-central Florida as a powerful hurricane before riding up the Florida coastline and then moving into the Carolinas. At this point, I can’t entirely discount that scenario. Broad troughing should remain in place across the northeastern U.S. This means that the primary flow down through the Ohio Valley and Mid-Atlantic will remain from the northwest. Embedded shortwave features moving within the flow and broad troughing could keep the Bermuda ridge weaker than what has previously been shown by the models. Plus, if Dorian were to move more slowly than currently anticipated, this would allow more time for troughing to weaken the Bermuda ridge. This needs to happen for the northward turn to occur more quickly. We can hope that a quicker turn to the north will prevent a Florida landfall, but uncertainty remains too high to say with confidence that this scenario will occur. Personally, if I were along the Florida east coast, I’d be planning for a major impact. For those in the Carolinas and eastern Georgia, flooding could become an issue, and at this point, I can’t discount a northern South Carolina and North Carolina landfall.
Right now, the likelihood of Hurricane Dorian entering the Gulf of Mexico has decreased quite a bit. Florida should continue to prepare for a potentially catastrophic and life-threatening event, and we will continue to make you aware of any changes in the forecast.