Potential Tropical Cyclone Five Discussion Number   1
NWS National Hurricane Center Miami FL       AL052024
500 PM AST Sun Aug 11 2024

NHC has been monitoring the a broad area of low pressure associated 
with a tropical wave over the tropical Atlantic during the past 
several days.  Satellite images and earlier ASCAT data indicate that 
the low has a broad circulation, but there is no evidence of a 
well-defined center yet.  The associated shower and thunderstorm 
activity is showing some signs of organization, but visible 
satellite imagery suggests that dry air is entraining into the 
circulation.  However, since the disturbance is forecast to become 
a tropical storm in the next day or so, and there is a risk of 
tropical-storm-force winds across portions of the Leeward Islands 
during that time, advisories are being initiated on Potential 
Tropical Cyclone Five.  The NOAA and Air Force Hurricane Hunters 
will be investigating this system on Monday.

The estimated motion of Potential Tropical Cyclone Five is 
285/18-kt.  The track guidance is in fairly good agreement on a fast 
west-northwestward motion through the next 36-48 h.  This motion 
should bring the system near or over the Leeward Islands on Tuesday. 
Thereafter, a deep-layer trough moving off the U.S. East Coast 
should approach this system, inducing a turn to the northwest by 
Wednesday and to the north thereafter.  This should bring the 
system in the general vicinity of the Virgin Islands and Puerto Rico 
Tuesday night, then emerging into the Atlantic north of Puerto Rico 
on Wednesday.  The NHC track forecast is based on a blend of the 
latest GFS and ECMWF models.  Users should keep in mind that the 
track forecasts for potential tropical cyclones are inherently more 
uncertain than normal since the system lacks a wellG��defined center.

Potential Tropical Cyclone Five is currently located in an 
environment of moderate easterly vertical wind shear.  Over the next 
day or two, the wind shear is forecast to decrease some while the 
disturbance moves into an increasingly unstable environment.  Given 
the current organizational state of the convection and low-level 
wind structure, the system likely needs at least one more day before 
it can organize into a tropical cyclone.  Around the time the system 
reaches the Leeward Islands, it will be moving into an increasingly 
conducive environment for strengthening.  Therefore, once the system 
is able to develop an inner core it should have an opportunity to 
strengthen at a faster rate.  The favorable environment will likely 
continue in the 3 to 5-day time frame, and this system is forecast 
to be a strengthening hurricane when it is moving northward over the 
western Atlantic.  The NHC intensity forecast is slightly below the 
intensity consensus in the short term, but falls in line with the 
consensus aids beyond a couple of days.


Key Messages:

1. The disturbance is expected to become a tropical storm before 
reaching the Leeward Islands, where Tropical Storm Watches are in 
effect.  Tropical storm conditions could begin on Tuesday for 
portions of the area.

2. Heavy rainfall may result in locally considerable flash flooding 
and mudslides in portions of the northern Leeward Islands Tuesday 
and Wednesday, and into Puerto Rico Wednesday through Thursday.

3. Additional watches or warnings will likely be required for the 
British and U.S. Virgin Islands, and Puerto Rico tonight or early 
Monday, and interests in these locations should monitor the progress 
of this system.

FORECAST POSITIONS AND MAX WINDS

INIT  11/2100Z 13.6N  48.0W   25 KT  30 MPH...POTENTIAL TROP CYCLONE
12H  12/0600Z 14.3N  51.2W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
24H  12/1800Z 15.2N  55.5W   35 KT  40 MPH...POTENTIAL TROP CYCLONE
36H  13/0600Z 15.9N  59.2W   40 KT  45 MPH...TROPICAL CYCLONE
48H  13/1800Z 17.0N  62.2W   45 KT  50 MPH
60H  14/0600Z 18.3N  64.4W   55 KT  65 MPH
72H  14/1800Z 19.8N  66.1W   65 KT  75 MPH
96H  15/1800Z 23.9N  67.4W   85 KT 100 MPH
120H  16/1800Z 27.7N  66.3W   95 KT 110 MPH

$$
Forecaster Hagen/Cangialosi