Tropical Storm Ernesto Discussion Number  26
NWS National Hurricane Center Miami FL       AL052024
1100 PM AST Sat Aug 17 2024

Satellite imagery and radar data from Bermuda continue to show 
limited convection associated with Ernesto, with the strongest 
convection in a poorly-defined eyewall in the northern semicircle. 
This is likely due to a tongue of dry air wrapping around the 
system from the northwest into the central core. The various 
subjective and objective satellite intensity estimates have 
decreased a little more since the last advisory, and based on this 
the initial intensity is lowered to 60 kt.

The initial motion is 030/7 kt.  This slow motion should continue 
for the next 6-12 h as a mid-latitude shortwave ridge passes to the 
north of Ernesto.  After that, southwesterly flow on the east side 
of a mid-latitude trough moving through the eastern United States 
should cause the cyclone to accelerate to the north-northeast, 
northeast, and eventually east-northeast.  This motion should bring 
the center just southeast of Newfoundland late Monday and Monday 
night, with the system moving into the open north Atlantic 
thereafter.  The track guidance remains tightly clustered, and the 
new forecast track has only minor changes from the previous track.

Little change in strength is expected tonight while Ernesto tries 
to mix out the dry air tongue.  After that, upper-level divergence 
is forecast to increase while the cyclone is still over relatively 
warm water.  This could allow some modest re-intensification as 
show by the dynamical models, and this remains reflected in the 
intensity forecast.  After 36 h, the cyclone should weaken as it 
moves over colder water and begins extratropical transition.  
Transition should be complete by 60 h, and and the post-tropical low 
is expected to degenerate to a trough over the northeastern 
Atlantic between 72-96 h.


Key Messages:

1. Ernesto is still moving slowly, and its impacts on Bermuda are
not quite over.  Strong winds, heavy rainfall, coastal flooding, and
battering waves should continue for a few more hours.  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  18/0300Z 33.9N  63.3W   60 KT  70 MPH
12H  18/1200Z 35.3N  62.9W   60 KT  70 MPH
24H  19/0000Z 37.9N  61.6W   65 KT  75 MPH
36H  19/1200Z 41.3N  58.8W   70 KT  80 MPH
48H  20/0000Z 44.7N  53.8W   65 KT  75 MPH
60H  20/1200Z 47.7N  46.2W   50 KT  60 MPH...POST-TROP/EXTRATROP
72H  21/0000Z 50.4N  36.9W   40 KT  45 MPH...POST-TROP/EXTRATROP
96H  22/0000Z...DISSIPATED

$$
Forecaster Beven