Tropical Storm Ernesto Discussion Number  11
NWS National Hurricane Center Miami FL       AL052024
500 AM AST Wed Aug 14 2024

Ernesto continues to gradually become better organized on satellite 
imagery and WSR 88-D radar data.  Very intense convection has 
developed near the center of the storm as well as in a strong band 
to the south across Puerto Rico.  Earlier Culebra reported 
sustained winds of 59 kt and that was the basis for the 60 kt 
estimate at 6Z.  While it is possible Ernesto is already a 
hurricane, radar data does not yet support an upgrade, so 60 kt 
remains the initial intensity. Two Hurricane Hunter aircraft are 
scheduled to be in the system later this morning.

The storm is moving northwestward at about 14 kt.  Ernesto is 
expected to turn north-northwestward later today and then move to 
the north or north-northeast for the next several days while it 
moves through a break in the subtropical ridge and interacts with a 
mid-latitude trough.  There are no notable changes to the NHC track 
forecast, with Ernesto forecast to stay offshore of the CONUS and 
make its closest approach to Bermuda on Saturday.

Radar data still suggests that Ernesto isn't fully vertically
aligned, with multiple attempts at eye formation failing, probably
due to dry air intrusions.  The large-scale conditions still appear
to be conducive for strengthening as the shear remains fairly low
and any residual dry air gradually mixes out of the core.  The bulk 
of the intensity guidance still shows Ernesto becoming a major 
hurricane over the western Atlantic in a couple of days, and the 
global models also depict a large and powerful hurricane.  Little 
change was made to the previous forecast, which remains near the 
model consensus.

It should be noted that all of the models are showing Ernesto
becoming quite a bit larger, which should send powerful swells
toward the land area across the western Atlantic.  Even if Ernesto
stays well offshore of the U.S. East Coast, beach goers should be 
aware of a significant risk of deadly rip currents beginning later 
this week.


Key Messages:

1. Tropical storm conditions are expected to continue over the
Virgin Islands, Puerto Rico, Culebra, and Vieques during the next
several hours.

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

3. Ernesto is likely to bring impacts to Bermuda late this week,
and interests there should monitor the progress of this system.

4. Swells generated by Ernesto are expected to affect portions of
the Virgin Islands, Puerto Rico, the Dominican Republic, the Turks
and Caicos, and the Bahamas during the next few days, and then reach
the east coast of the United States and Bermuda late this week and
into the weekend. These swells are likely to cause life-threatening
surf and rip current conditions.


FORECAST POSITIONS AND MAX WINDS

INIT  14/0900Z 19.5N  66.6W   60 KT  70 MPH
12H  14/1800Z 21.1N  67.8W   70 KT  80 MPH
24H  15/0600Z 23.6N  68.9W   85 KT 100 MPH
36H  15/1800Z 25.7N  68.8W   95 KT 110 MPH
48H  16/0600Z 27.6N  67.6W  100 KT 115 MPH
60H  16/1800Z 29.5N  66.2W  100 KT 115 MPH
72H  17/0600Z 31.4N  65.5W   95 KT 110 MPH
96H  18/0600Z 35.0N  65.0W   90 KT 105 MPH
120H  19/0600Z 40.5N  62.5W   80 KT  90 MPH

$$
Forecaster Blake