[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT41 KNHC 221453
TCDAT1

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.


FORECAST POSITIONS AND MAX WINDS

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
This weather bulletin was brought to you by:
www.nashvilleweather.net