Philadelphia, PA - As of Friday morning the National Hurricane Center downgraded Florence to a tropical storm with winds at 60 mph. Florence continues to sit in a harsh environment featuring strong wind shear and dry air that has disrupted the storm from development. The bad news is this will not last as the system will move back into a region of favorable development over the next 24 hours.
FLORENCE TO AWAKE..
Florence is expected to move into a region favorable for further development. Satellite data this morning shows the system is now over a region of warmer water and is expected to intensify back to a hurricane some time Saturday. The national hurricane center track remains unchanged and keep Florence on a west heading over the next several days. The track will keep the system over this favorable environment going into the weekend and that should be enough to bring Florence back to a strong category 2 hurricane.
WHERE WILL SHE GO?
Florence's window to escape out to sea is just about closed. The guidance remains consistent that she will pass by Bermuda in route to the east coast by later next week. Beyond that it's a crap shoot as to whether Florence will make a landfall over the southeast United States or as far north as New Jersey. The data supports a number of possibilities due to a cold front that will be located over the central US by the middle of next week. If this front is further east it maybe enough to turn the system out to sea. However, guidance on the GFS model suggests a slower front and strong high positioned over the system that could allow the storm to drift onshore. Some data supports a land falling hurricane over MDVANC but again that would be speculating based on where the guidance feels the "cold front" is located today! At this time forecasters such as myself, Kathy, Sue, and Scott will monitor trends in the data and not so much the exact simulation as to where the model things landfall will happen
THE SCENARIOS AHEAD
I believe there are 3 scenarios that need to be addressed as we move into next week.
Scenario 1: Storm clips the eastern USA.
A slow moving storm like Florence will have a number of influences later next week that could turn the system out to sea. With a high building to the north and departing to the east we may see some weakness develop to allow the system to turn north and eventually north east. In a case like this we would see very rough surf and gusty winds along the beaches. Rain bands would make it inland but the storm will remain offshore. This scenario would be reminiscent of Irene 2011 but to an even lesser scale.
Scenario 2: Landfall over the SE USA
The aforementioned cold front stays west while Florence stays on a due west heading with a high centered to the north. In a situation like this we will see the system SLAM between SC-VA and come inland. The is a bad scenario that would put PANJDE on the severe storm side of the system if the storm rides north and west. We'd see very strong winds, possible tornadoes, and of course flooding rains inland if the strike is closer to VAMD vs SC or NC. This type of scenario would be similar to a hurricane Connie in 1955, Isabel 2003, or hurricane hazel 1954.
Scenario 3: Landfall over MDDE
This is weighted MUCH lower but still an option on the table. We'd obviously be talking worst case scenario impacts for the Delaware Valley. Unfortunately history only gives us a few analogs to compare this to. The 1944 great Atlantic Hurricane (no name), Hazel, and Sandy. All extremely powerful events that impacted the region greatly. This type of scenario would suggest the cold front much further east but in a position that allows the storm to go NNW and then north. To align and track a storm in such a way suggests an rare 100 year type of event. The great news is the guidance is not compelling enough to weight this scenario highest on the scale.