Hurricane Ernesto Discussion Number  13
NWS National Hurricane Center Miami FL       AL052024
500 PM AST Wed Aug 14 2024

Visible satellite imagery shows that Ernesto's cloud field is 
gradually expanding, and there have been hints of an eye potentially 
forming in the Central Dense Overcast.  The Air Force Reserve 
mission from a few hours ago found that the central pressure had 
fallen to 989 mb, but there were no indications that the maximum 
winds were any higher than 65 kt.  The initial intensity is 
therefore held at that level, which is also supported by the latest 
satellite intensity estimates.

Ernesto is still moving northwestward but continues to turn to the 
right, and the initial motion is 325/14 kt.  A turn toward the 
north-northwest and north is expected tonight and on Thursday as 
the hurricane moves through a break in the subtropical ridge, but 
the trough causing this break is forecast to leave Ernesto behind 
later in the week.  The result is that Ernesto is likely to slow 
down while it passes very near Bermuda Friday night and Saturday.  
Thereafter, a second trough approaching from the west should cause 
Ernesto to accelerate toward the northeast, near or just south of 
Atlantic Canada.  The track models are in very good agreement on 
this scenario, but there is a bit of east-to-west spread after 48 
hours.  The new NHC track forecast has been nudged eastward after 
48 hours to be close to the multi-model consensus aids, although at 
this time it is too soon to know exactly how close Ernesto's center 
will move to Bermuda this weekend.

An environment of warm ocean waters (around 29 degrees Celsius) and 
low to moderate shear should allow Ernesto to strengthen gradually 
during the next few days.  Most of the intensity models indicate 
that the hurricane should peak in intensity in about 48 hours.  At 
that time, the official forecast shows a peak of 100 kt--major 
hurricane--which is near the top end of the guidance and close to 
the HAFS-B, COAMPS-TC, and HCCA models.  A weakening trend should 
begin after 48 hours due to moderate shear and a drier, more stable 
atmosphere, but the weakening is likely to be gradual.  As a result, 
the official forecast keeps Ernesto as a hurricane throughout the 
5-day forecast period.


Key Messages:

1. Hurricane conditions are possible on Bermuda on Saturday, with 
tropical storm conditions possible by Friday afternoon.  Rainfall 
associated with Ernesto may begin to affect Bermuda as early as 
Thursday and result in flash flooding across Bermuda later in the 
week and this weekend.

2. Heavy rainfall will be diminishing across Puerto Rico into the 
Virgin Islands this evening.  Locally considerable flash flooding 
and mudslides will continue through tonight over the Virgin Islands 
and into portions of Puerto Rico.

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  14/2100Z 21.7N  68.3W   65 KT  75 MPH
12H  15/0600Z 23.5N  69.0W   75 KT  85 MPH
24H  15/1800Z 25.7N  69.0W   85 KT 100 MPH
36H  16/0600Z 27.7N  68.0W   95 KT 110 MPH
48H  16/1800Z 29.5N  66.6W  100 KT 115 MPH
60H  17/0600Z 31.3N  65.7W   95 KT 110 MPH
72H  17/1800Z 32.9N  65.4W   90 KT 105 MPH
96H  18/1800Z 37.0N  64.2W   85 KT 100 MPH
120H  19/1800Z 43.4N  58.2W   80 KT  90 MPH

$$
Forecaster Berg