Official Discussion issued by the National Hurricane Center

Fifteen (AL152020) DATA RELEASED: 9/1/2020 3:00:00 PM UTC

Copy of official data

Tropical Depression Fifteen Discussion Number   4
NWS National Hurricane Center Miami FL       AL152020
1100 AM EDT Tue Sep 01 2020

The depression has become better organized this morning with the 
center embedded in the western side of a growing area of deep 
convection.  An earlier buoy report recorded adjusted maximum winds 
of 32 kt, and roughly half of the estimates show that the depression 
is a tropical storm.  Conservatively, the winds will be held at 30 
kt until we will see what the scatterometer shows this afternoon.  
Increasing shear is expected to limit any significant strengthening, 
although it does seem more likely than not that this system will 
barely make it to a tropical storm later today.  The shear is 
forecast to get quite strong by tomorrow afternoon, so weakening is 
anticipated by then, and persistence of that shear is expected to 
cause the cyclone to decay into a remnant low in about 48 hours.  
While the initial part of the forecast is a little higher than the 
last one, this change is really in the noise level for intensity 
prediction and is only noticeable because of the tropical storm 
threshold.

The initial motion has turned toward the east-northeast or 060/12 
kt.  There is reasonable agreement among the guidance that this 
motion will continue through tomorrow, and then become eastward 
during the next 2-3 days around the northern side of the subtropical 
ridge, followed by a northeastward turn by day 4. Similar to the 
last forecast, most of the uncertainty is with the speed, rather 
than the direction of the cyclone. The new forecast is closer to the 
faster guidance and the previous NHC track prediction.  Dissipation 
is shown at 120h, although a few models have it occuring as early as 
days 2-3.


FORECAST POSITIONS AND MAX WINDS

INIT  01/1500Z 34.7N  73.1W   30 KT  35 MPH
12H  02/0000Z 35.6N  71.1W   35 KT  40 MPH
24H  02/1200Z 36.5N  68.3W   35 KT  40 MPH
36H  03/0000Z 37.2N  65.1W   30 KT  35 MPH
48H  03/1200Z 37.3N  62.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
60H  04/0000Z 37.0N  59.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
72H  04/1200Z 37.0N  57.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
96H  05/1200Z 39.5N  52.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  06/1200Z...DISSIPATED

$$
Forecaster Blake