As of 5 pm AST, Florence is a category 1 hurricane with maximum sustained winds of 85 mph. Over the last several days, Florence has raised some concerns given that forecast model guidance has oscillated back and forth between an East Coast impact and an out-to-sea solution. Most of the model guidance has really struggled with where Florence will be positioned beyond 5 days. Ridging has persisted across the eastern U.S. and extends just off the East Coast, and by late weekend to early next week, a trough is going to begin moving across the northwest Atlantic, while ridging will remain parked across the southeastern U.S. and extend off the southeast coast.
Since Bermuda ridging is not well-established across the central North Atlantic, Florence should continue gaining latitude over the next several days. However, if Florence were to weaken quite a bit in the short to medium-range, there is the possibility that it could have a more westward component to its track in the coming days. The concern has been that if Florence moves on a more westward track, that it could sneak under the ridge instead of getting picked up by the trough, which would steer the system towards the East Coast. Yes, I can’t discount that possibility, but I think that it is the least likely scenario.
I made a graphic that shows tropical cyclones since the 1800s that have tracked very close to the current 5-day projected path of Hurricane Florence. If a tropical cyclone tracked within 2 degrees of Florence’s current position and within 4 degrees of its predicted position at days 4 and 5, its track was plotted as a red line. The black dots represent the National Hurricane Center’s current track forecast for Florence. Even previous systems that tracked a bit to the south of the NHC’s forecasted position for Florence on days 4 and 5 eventually curved northward and went out to sea. Out of the 71 cases selected, none hit the East Coast, and only one impacted the U.S. In other words, if history is any indication of what will happen with Florence, it needs to remain considerable farther to the south in the coming days than what is currently being predicted for the probability of an East Coast impact to increase.
Physically, the two scenarios are plausible; thus, the East Coast needs to continue to monitor closely. However, with all things considered, Firsthand Weather is currently leaning quite heavily towards the out-to-sea solution. Yes, we could be wrong, since predicting the projected path of a tropical system in the middle of the Atlantic beyond 5 days is very challenging. Please continue to check back with us on the website and on Facebook/Twitter on a daily basis in case anything changes.