Hurricane Ernesto Discussion Number  15
NWS National Hurricane Center Miami FL       AL052024
500 AM AST Thu Aug 15 2024

Ernesto has strengthened overnight.  Satellite images show that a 
more symmetric area of deep convection has formed near the center, 
with a rather large curved band wrapping in all quadrants of the 
hurricane. The initial intensity is set to 75 kt, matching the TAFB 
and SAB estimates, though recent imagery suggests that could be a 
little conservative.  An Air Force Reserve Hurricane Hunter 
Aircraft is scheduled to be in the hurricane in a few hours.

Ernesto has turned northward and is moving at about 11 kt.  The 
models remain in good agreement that the hurricane should turn to 
the northeast during the next day or so while moving through a break 
in the subtropical ridge over the western Atlantic towards a 
mid-latitude trough.  However, the trough departs by the weekend, 
causing Ernesto to move slower to the north-northeast or north while 
the hurricane approaches Bermuda Friday night and Saturday.  Later 
this weekend, a second trough will move across the eastern U.S., and 
Ernesto should accelerate northeastward early next week within the 
deep-layer southwesterly flow ahead of this feature. The NHC track 
forecast is very close to the previous one as the track guidance 
remains in good overall agreement. 

While the shear near Ernesto remains low, a large dry slot continues 
to wrap near the core, preventing anything other than slow 
intensification so far.  Most of the guidance gradually intensifies 
the system during the next day or so as the very warm waters and 
light-to-moderate shear outweigh the effects of the dry air.  Little 
change was made to the intensity forecast, and all of the guidance 
show this system as a large hurricane near Bermuda.  There remains 
some indications that positive interactions with the second upper 
trough and warmer than normal waters should cause the system to keep 
much of its strength north of Bermuda, and the new forecast reflects 
this.  All of the guidance now show Ernesto as post-tropical by 120 
h, and so does the NHC forecast.


Key Messages:

1. Ernesto is expected to approach Bermuda late Friday and be near 
the island Saturday and Saturday night.  A prolonged period of 
strong winds and storm surge is expected on Bermuda beginning late 
Friday, and a hurricane warning has been issued for the island.  
Preparations to protect life and property should be rushed to 
completion.

2. Rainfall associated with Ernesto is expected to begin to affect 
Bermuda later today and may result in flash flooding Friday through 
this weekend.

3. Even though Ernesto is forecast to remain well offshore the U.S.
East Coast, swells generated by the storm are expected to reach the
area late this week and into the weekend.  Beach goers should be
aware of a significant risk of life-threatening surf and rip
currents, and stay out of the water if advised by lifeguards.  Surf
and rip currents are also possible on the Virgin Islands, Puerto
Rico, the Dominican Republic, the Turks and Caicos, and the Bahamas
during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT  15/0900Z 23.9N  69.1W   75 KT  85 MPH
12H  15/1800Z 25.4N  69.1W   85 KT 100 MPH
24H  16/0600Z 27.4N  68.1W   95 KT 110 MPH
36H  16/1800Z 29.3N  66.7W  100 KT 115 MPH
48H  17/0600Z 31.1N  65.7W   95 KT 110 MPH
60H  17/1800Z 32.6N  65.4W   90 KT 105 MPH
72H  18/0600Z 34.3N  65.1W   90 KT 105 MPH
96H  19/0600Z 39.7N  62.3W   90 KT 105 MPH
120H  20/0600Z 47.0N  52.0W   65 KT  75 MPH...POST-TROPICAL

$$
Forecaster Blake