Official Discussion issued by the National Hurricane Center

Ernesto (AL052024) DATA RELEASED: 8/19/2024 3:00:00 AM UTC

Copy of official data

Hurricane Ernesto Discussion Number  30
NWS National Hurricane Center Miami FL       AL052024
1100 PM AST Sun Aug 18 2024

Ernesto continues to have a good structure this evening with a
partly cloud-filled eye surrounded by bands of convection, although 
the convective cloud tops are not quite as cold as they were 6 h 
ago. Subjective Dvorak intensity estimates from TAFB and SAB are now
near 65 kt, while various objective estimates are now near 75 kt.
The initial intensity is increased to 70 kt based on a blend of
these data.

Some additional strengthening is possible during the next 6-12 h
before Ernesto moves north of the north wall of the Gulf Stream.
After that, the system should quickly decay as it moves over colder
water and encounters increasing southwesterly shear.  The cyclone
should become an extratropical low by 36 h as it passes south of
southeastern Newfoundland, and by 72 h it should be absorbed into a
larger non-tropical low developing south of Iceland.  The new
intensity forecast is near the upper edge of the intensity guidance
for the first 12 h, and after that lies near the intensity
consensus.

The initial motion is now 030/17 kt. A northeastward motion at a
faster forward speed is expected over the next 24-36 h as Ernesto
becomes caught up in the flow between a large deep-layer trough
over the eastern U.S. and a subtropical ridge centered to the
hurricane's southeast. This motion should bring the center south
of southeastern Newfoundland late Monday night or early Tuesday
morning, with most of the wind field staying offshore.  A more
east-northeastward motion is expected thereafter before the cyclone
becomes absorbed by the aforementioned larger extratropical
cyclone. The tightly clustered track guidance has shifted a little 
to the north since the last advisory, so the new track forecast is a
little north of the previous track.


Key Messages:

1. Even though Ernesto is forecast to remain well offshore of the
U.S. East Coast, swells generated by the hurricane will continue to
affect the area through the early part of this 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.

2. Ernesto could bring wind, wave, and rain impacts to portions of
southeastern Newfoundland Monday night into Tuesday morning.
Breaking waves could bring the possibility of coastal flooding,
particularly along southwest-facing shorelines from Bunin east to
Avalon regions. For additional impact specific information, please
see statements issued by the Canadian Hurricane Centre.


FORECAST POSITIONS AND MAX WINDS

INIT  19/0300Z 38.5N  61.4W   70 KT  80 MPH
12H  19/1200Z 40.9N  59.3W   75 KT  85 MPH
24H  20/0000Z 44.3N  54.3W   65 KT  75 MPH
36H  20/1200Z 47.4N  46.6W   55 KT  65 MPH...POST-TROP/EXTRATROP
48H  21/0000Z 50.0N  35.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
60H  21/1200Z 52.5N  24.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
72H  22/0000Z...DISSIPATED

$$
Forecaster Beven