Tropical Storm Ernesto Discussion Number  10
NWS National Hurricane Center Miami FL       AL052024
1100 PM AST Tue Aug 13 2024

Aircraft data, surface observations, and NWS radar images indicate 
Ernesto passed over the Virgin Islands around 00 UTC this evening. 
The tropical cyclone remains asymmetric, as NOAA Tail Doppler Radar 
data show the strongest winds and heaviest rainfall are generally 
confined to the northern and eastern semicircles of the storm. Data 
from the NOAA and Air Force Hurricane Hunters indicate the central 
pressure of Ernesto has fallen to around 998-999 mb, and an earlier 
aircraft pass through the eastern part of the storm found peak 
700-mb flight-level winds of 60 kt. Based on these data, the initial 
intensity is set at 55 kt, which matches the latest Dvorak current 
intensity estimates from TAFB and SAB.

The latest aircraft fixes and radar data show Ernesto has turned 
northwestward (305/15 kt). Overnight, Ernesto will move away from 
the Virgin Islands and pass to the northeast and north of Puerto 
Rico. Then, Ernesto is expected to move northwestward to northward 
during the next couple of days toward a break in the subtropical 
ridge. By late week, the influence of a deep-layer trough over the 
western Atlantic should cause Ernesto to turn north-northeastward, 
although the cyclone is forecast to slow down a bit after the trough 
passes to its north. There are no notable changes to the NHC track 
forecast, with Ernesto forecast to make its closest approach to 
Bermuda Friday night into Saturday. 

The radar structure of Ernesto indicates it has not yet solidified 
an inner core. However, once this occurs, the atmospheric and 
oceanic conditions appear conducive for significant strengthening 
over the next few days. Most of the hurricane regional models and 
statistical guidance show Ernesto becoming a major hurricane over 
the western Atlantic late this week, and the global models 
(particularly the GFS) show significant deepening of the low. Based 
on the latest guidance trends, the NHC intensity forecast has been 
raised slightly during the middle portion of the forecast period and 
now shows Ernesto becoming a major hurricane on Friday.


Key Messages:

1. Tropical storm conditions are expected to continue over the 
Virgin Islands and Puerto Rico through early Wednesday, with 
hurricane conditions possible on the Virgin Islands, Culebra, and 
Vieques.

2. Heavy rainfall may result in locally considerable flash flooding 
and mudslides over the Virgin Islands and into portions of Puerto 
Rico tonight through Wednesday.

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  14/0300Z 18.8N  65.3W   55 KT  65 MPH
12H  14/1200Z 20.3N  66.7W   65 KT  75 MPH
24H  15/0000Z 22.4N  68.3W   80 KT  90 MPH
36H  15/1200Z 24.4N  68.8W   90 KT 105 MPH
48H  16/0000Z 26.3N  68.3W   95 KT 110 MPH
60H  16/1200Z 28.1N  67.2W  100 KT 115 MPH
72H  17/0000Z 29.9N  66.2W  100 KT 115 MPH
96H  18/0000Z 34.0N  64.5W   90 KT 105 MPH
120H  19/0000Z 38.0N  63.0W   85 KT 100 MPH

$$
Forecaster Reinhart