Official Discussion issued by the National Hurricane Center

Ernesto (AL052024) DATA RELEASED: 8/14/2024 3:00:00 PM UTC

Copy of official data

Hurricane Ernesto Discussion Number  12
NWS National Hurricane Center Miami FL       AL052024
1100 AM AST Wed Aug 14 2024

An Air Force Reserve Hurricane Hunter aircraft measured a peak
700-mb flight-level wind of 70 kt northeast of Ernesto's center, and
the crew reported a 50 percent eyewall.  In addition, Tail Doppler
radar from the NOAA P-3 aircraft measured winds over 75 kt at an
elevation of 500 meters.  Based on these data, Ernesto is upgraded
to a 65-kt hurricane.

Ernesto continues to move northwestward, or 310/14 kt, but is
expected to turn north-northwestward and northward later today and
tonight as it moves through a break in the subtropical ridge caused
by a deep-layer trough off the east coast of the United States. This
trough is expected to leave Ernesto behind later this week, which
should cause a reduction in speed on Saturday and Sunday while the
storm is passing Bermuda.  By early next week, a second trough
moving across the eastern United States should cause Ernesto to
accelerate toward the north and north-northeast over the waters
south of Atlantic Canada.  The track guidance is in good agreement
during the first 48 hours, and the official forecast was only
shifted slightly westward to account for Ernesto's recent motion.
After 48 hours, there is more divergence in the track models, with
the GFS on the eastern edge of the envelope while the ECMWF shows
less turning and is on the western edge of the envelope.  The NHC
forecast has been nudged westward during this period and is very
close to the dynamical hurricane models.

Although Ernesto is moving over very warm waters, the hurricane
might have to deal with bouts of increased shear and nearby dry
air during the next several days.  That said, the intensity
guidance shows continued gradual strengthening, and the official
forecast still reflects the possibility of Ernesto becoming a major
hurricane in about 48 hours.  Much of the intensity guidance has
come down on the peak intensity this cycle, but for now we'll
maintain continuity and wait to see if this trend continues.


Key Messages:

1. Heavy rainfall will result in locally considerable flash flooding
and mudslides today over the Virgin Islands and into portions of
Puerto Rico.

2. Tropical storm conditions, especially in gusts, are expected to
continue over the Virgin Islands, Puerto Rico, Culebra, and Vieques
through today.

3. Ernesto is likely to bring impacts to Bermuda late this week, and
interests there should monitor the progress of this system.  A
Hurricane Watch may be required later today.

4. 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  14/1500Z 20.5N  67.6W   65 KT  75 MPH
12H  15/0000Z 22.3N  68.7W   70 KT  80 MPH
24H  15/1200Z 24.5N  69.2W   80 KT  90 MPH
36H  16/0000Z 26.6N  68.6W   90 KT 105 MPH
48H  16/1200Z 28.5N  67.2W  100 KT 115 MPH
60H  17/0000Z 30.4N  66.1W   95 KT 110 MPH
72H  17/1200Z 32.0N  65.8W   90 KT 105 MPH
96H  18/1200Z 36.0N  65.4W   85 KT 100 MPH
120H  19/1200Z 42.6N  61.0W   80 KT  90 MPH

$$
Forecaster Berg