Hurricane Ernesto Discussion Number  24
NWS National Hurricane Center Miami FL       AL052024
1100 AM AST Sat Aug 17 2024

An Air Force Reserve Hurricane Hunter aircraft made a couple of 
passes through Ernesto this morning and only found 700-mb flight 
level winds as high as 74 kt--significantly lower than the maximum 
winds reported by the mission yesterday evening and overnight.  The 
initial intensity is therefore set at 70 kt for this advisory, and 
even that could be a bit generous.  Although the central pressure 
has not risen much, Ernesto's wind field has continued to expand, 
and the hurricane is now exhibiting a large rain-free center region 
that is just about to move past Bermuda.

The forward motion has slowed a bit more and is now estimated to be 
north-northeastward (025 degrees) at 7 kt.  Ernesto has been left 
behind by a shortwave trough now located near Newfoundland, and 
therefore a continued slow motion toward the north-northeast is 
forecast for the next day or so until another trough to the west 
gets closer.  Ernesto should begin accelerating on Sunday as it 
heads toward Atlantic Canada, turning northeastward and passing 
very near southeastern Newfoundland late Monday and Monday night.  
The guidance has again slowed down on this cycle, and the NHC 
forecast has been adjusted accordingly.

Although deep-layer shear is forecast to diminish a bit during the 
next 24 hours while Ernesto remains over waters of 28 degrees 
Celsius, the structure of the hurricane and dry air within the 
circulation suggest that the storm may not be able to re-intensity 
much, if at all.  The NHC intensity forecast is near the top end of 
the guidance and does keep Ernesto as a hurricane for the next 48 
hours.  Weakening is expected after that time, and global model 
fields suggest Ernesto should become extratropical by 72 hours 
while or just after passing Newfoundland.  A 96-hour point is 
provided for continuity, but both the GFS and ECMWF indicate that 
the circulation could open up into a trough over the north Atlantic 
by then.


Key Messages:

1. Ernesto is moving slowly, and its impacts on Bermuda are 
not over.  Strong winds, heavy rainfall, coastal flooding, and 
battering waves are likely through tonight.  The heavy rains will 
likely result in considerable life-threatening flash flooding, 
especially in low-lying areas on the island.

2. Even though Ernesto is forecast to remain well offshore the U.S. 
East Coast, swells generated by the hurricane are expected to affect 
the area through early next week.  Beach goers should be aware that 
there is a significant risk of life-threatening surf and rip 
currents, and should stay out of the water if advised by lifeguards. 
Surf and rip currents are also possible on the Bahamas, Bermuda, and 
Atlantic Canada during the next few days.

3. Ernesto could bring wind, wave, and rain impacts to portions of 
southeastern Newfoundland late Monday and Monday night.


FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 32.9N  64.4W   70 KT  80 MPH
12H  18/0000Z 33.7N  63.9W   65 KT  75 MPH
24H  18/1200Z 35.3N  63.3W   65 KT  75 MPH
36H  19/0000Z 37.9N  62.0W   65 KT  75 MPH
48H  19/1200Z 41.3N  59.5W   70 KT  80 MPH
60H  20/0000Z 44.9N  54.7W   60 KT  70 MPH
72H  20/1200Z 47.7N  47.2W   50 KT  60 MPH...POST-TROP/EXTRATROP
96H  21/1200Z 51.2N  27.8W   35 KT  40 MPH...POST-TROP/EXTRATROP
120H  22/1200Z...DISSIPATED

$$
Forecaster Berg