Hurricane Ernesto Discussion Number  17
NWS National Hurricane Center Miami FL       AL052024
500 PM AST Thu Aug 15 2024

The inner core of Ernesto continues to be plagued by dry air 
intrusion.  A NOAA Hurricane Hunter aircraft reported that Ernesto 
has yet to close off an eyewall.  While the minimum central sea 
level pressure has fallen to an estimated 972 mb based on dropsonde 
data, the maximum flight-level winds are still at 86 kt, similar to 
the earlier mission.  Therefore, the initial intensity is held at 
75 kt for this advisory cycle.

Ernesto has turned northward, with an estimated motion of 360/11 kt. 
The storm is currently being steered by the flow between the 
subtropical ridge centered over the north Atlantic Ocean and a 
mid-latitude trough just off the eastern seaboard of North America.  
This hurricane is expected to gradually turn more northeastward and 
slow down over the next day or so as the trough lifts out to the 
northeast.  A subsequent trough is forecast to approach the New 
England coast on Sunday and accelerate Ernesto off to the 
northeast.  The official track forecast is virtually unchanged from 
the previous prediction and lies between the various consensus aids. 
Based on the forecast, Ernesto is expected to pass near or over 
Bermuda on Saturday and near or east of Atlantic Canada on Monday.

Warm waters and relatively low vertical wind shear should allow 
Ernesto to gradually intensify over the next 12 hours or so.  
Still, the mid-level atmospheric moisture is expected to be marginal 
and the system could continue to experience dry air intrusions.  
Global models suggest that while the vertical wind shear could 
begin to increase within a day, Ernesto may be positioned in a 
region relative to the departing trough where it could capitalize on 
enhanced outflow and continue to strength.  By the weekend, 
atmospheric conditions should become less favorable and gradually 
weaken the hurricane.  Still, Ernesto is expected to remain a 
powerful hurricane as it moves north of Bermuda.  Little changes 
have been made to the latest NHC intensity forecast, which lies 
near the top of the model guidance envelope.


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 is in effect 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 this evening 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 during the next few days, including over 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
Dominican Republic, the Turks and Caicos, the Bahamas, and Bermuda
during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 26.1N  68.9W   75 KT  85 MPH
12H  16/0600Z 27.6N  68.1W   85 KT 100 MPH
24H  16/1800Z 29.5N  66.9W   95 KT 110 MPH
36H  17/0600Z 31.3N  65.8W   90 KT 105 MPH
48H  17/1800Z 32.9N  65.2W   80 KT  90 MPH
60H  18/0600Z 34.5N  64.9W   80 KT  90 MPH
72H  18/1800Z 36.9N  63.7W   80 KT  90 MPH
96H  19/1800Z 43.5N  57.9W   70 KT  80 MPH
120H  20/1800Z 50.1N  43.0W   50 KT  60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Bucci/Onderlinde