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.
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
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.
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.
Matthew Holliday (Curriculum Vitae - Resume) is a graduate of the University of Oklahoma, where he completed a B.S. in Meteorology and a B.S. in Geographic Information Science. He completed his master's degree in meteorology and climatology at Mississippi State University and is currently pursing a Ph.D. in Earth and Atmospheric Sciences.