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Tropical Depression Seven Forecast Discussion


000
WTNT42 KNHC 141500
TCDAT2

Tropical Depression Seven Discussion Number   1
NWS National Hurricane Center Miami FL       AL072022
1100 AM AST Wed Sep 14 2022

Visible satellite imagery shows that the circulation associated 
with the area of low pressure in the tropical Atlantic has become 
better defined.  The associated convection has persisted overnight 
and this morning, and although it is confined to the eastern 
portion of the circulation it has enough organization to classify 
the system as a tropical depression.  The initial intensity is set 
at 30 kt, which is a little above the latest TAFB Dvorak 
classification of T1.5, but in line with overnight scatterometer 
data. 

Moderate westerly shear and a dry mid-level atmosphere are expected 
to prevent significant intensification, but some modest 
strengthening is possible over the next day or two, and the NHC 
forecast calls for the depression to become a tropical storm tonight 
or Thursday. After the system moves into the eastern Caribbean, the 
westerly shear is forecast to increase somewhat and the global 
models suggest that the system could struggle to maintain its 
closed circulation after that time.  The NHC intensity forecast is 
a little above the IVCN intensity forecast, and maintains the 
system as a tropical cyclone through the forecast period.  Weakening 
is indicated by day 5 when the system is forecast to interact with 
Hispaniola. 

The depression is moving westward or 280/12 kt.  The cyclone is 
forecast to move slightly north of due westward along the south 
side of a low to mid-level ridge that is anchored over the central 
and western Atlantic.  Although the track guidance is tightly 
clustered, there are some differences in forward speed with the 
ECMWF much faster than the GFS.  The NHC forecast lies near the 
middle of the guidance envelope and is near the TVCA and GFEX 
consensus aids to account for the differences in the forward speed. 

Key Messages:

1.  The system is expected to move through the Leeward Islands on 
Friday or Friday night, bringing heavy rainfall and possible wind 
impacts. Interests in the Leeward Islands should monitor the 
progress of the depression as tropical storm watches could be 
required for some islands later today. 

2.  The system could move near or over portions of the Virgin 
Islands, Puerto Rico, and Hispaniola this weekend and early next 
week, potentially bringing heavy rainfall and some wind impacts to 
these areas, and interests there should monitor the progress of the 
depression. 


FORECAST POSITIONS AND MAX WINDS

INIT  14/1500Z 16.6N  49.6W   30 KT  35 MPH
 12H  15/0000Z 16.7N  51.5W   35 KT  40 MPH
 24H  15/1200Z 16.8N  53.9W   40 KT  45 MPH
 36H  16/0000Z 16.9N  56.5W   40 KT  45 MPH
 48H  16/1200Z 17.0N  59.3W   40 KT  45 MPH
 60H  17/0000Z 17.1N  62.0W   40 KT  45 MPH
 72H  17/1200Z 17.4N  64.6W   40 KT  45 MPH
 96H  18/1200Z 18.0N  68.5W   40 KT  45 MPH
120H  19/1200Z 19.1N  71.7W   30 KT  35 MPH...INLAND

$$
Forecaster Brown



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