Atlantic Hurricane and Tropical Cyclone Track Updates

Tropical Depression Peter Forecast Discussion

WTNT41 KNHC 221453

Tropical Depression Peter Discussion Number  16
NWS National Hurricane Center Miami FL       AL162021
1100 AM AST Wed Sep 22 2021

Peter is barely hanging on to its status as a tropical cyclone this 
morning. While still closed, the low-level circulation continues to 
look increasingly diffuse on satellite imagery. In addition, the 
convective activity, which lacks much organization, remains 
displaced well to the northeast by moderate to strong southwesterly 
vertical wind shear. A blend of the latest subjective satellite 
intensity estimates support keeping Peter as a 30-kt tropical 
depression this advisory. As has been the story for the last few 
days, Peter will continue to deal with a lethal combo of 25-35 kt 
southwesterly vertical wind shear while embedded in a relatively dry 
mid-level air environment. These factors should ultimately lead to 
Peter's demise as a tropical cyclone, with the latest NHC intensity 
forecast moving the timing up for post-tropical remnant low status 
to 24 hours. This degeneration could occur as soon as this afternoon 
if more organized convection does not soon return near the center. 
Alternatively, Peter may also open up into a trough at any time 
since the center continues to gradually lose definition.

Similar to prior nights, Peter made another jog to the left after 
overnight convection diminished near the center. More recently, the 
depression has begun a slow north-northwestward motion estimated at 
330/6 kt. The cyclone is expected to turn northward and then 
northeastward over the next 24 hours as low-level ridging breaks 
down south of a deep-layer trough located near Bermuda. The NHC 
track forecast early on is a bit west of the previous one due to the 
leftward initial position, but falls in line to a similar track 
after 24 hours, continuing to split the difference between the GFS 
and ECMWF models.

As Peter moves poleward away from Puerto Rico, Hispaniola, and the 
Virgin Islands, the threat of heavy rainfall for these regions 
associated with the system has diminished. 


INIT  22/1500Z 21.6N  66.9W   30 KT  35 MPH
 12H  23/0000Z 22.3N  67.2W   30 KT  35 MPH
 24H  23/1200Z 23.3N  67.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  24/0000Z 24.2N  66.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  24/1200Z 25.1N  66.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  25/0000Z 26.3N  65.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  25/1200Z...DISSIPATED

Forecaster Papin

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