Official Discussion issued by the National Hurricane Center

Twenty (AL202020) DATA RELEASED: 9/14/2020 3:00:00 AM UTC

Copy of official data

Tropical Depression Twenty Discussion Number   6
NWS National Hurricane Center Miami FL       AL202020
1100 PM AST Sun Sep 13 2020

The depression continues to march west-northwestward with little 
change in its structure so far. Scatterometer data near 00Z revealed 
that the system is still elongated southwest to northeast with 
maximum winds near 30 kt. Convection has become a little more 
concentrated to the southwest of the depression's center during the 
past few hours, so perhaps this is a sign that it will start getting 
organized soon.

As long as the depression remains disorganized, only minimal 
strengthening is likely. However, once the system comes together, 
all indications are that it will strengthen, perhaps significantly 
so. The cyclone still has several days to strengthen within a 
low-shear/high-SST environment, and even the global models 
explicitly forecast the system to become a hurricane. The NHC 
intensity forecast is unchanged and still brings the depression to 
major hurricane strength by the middle of the week. Some of the 
dynamical hurricane models indicate it could strengthen faster than 
that, so this forecast could wind up being conservative.

The depression appears to be moving generally west-northwestward. A 
large mid-level ridge over the central Atlantic should keep the 
cyclone on this general heading for the next couple of days. After 
that, the ridge is forecast to move north and east, and the 
strengthening cyclone should turn toward the northwest in response. 
While the exact details vary from model to model, all of the 
dynamical track guidance supports this general scenario. The NHC 
forecast is based heavily on the model consensus and lies near the 
middle of the guidance envelope.


INIT  14/0300Z 13.0N  39.0W   30 KT  35 MPH
12H  14/1200Z 13.5N  41.2W   35 KT  40 MPH
24H  15/0000Z 13.9N  43.7W   45 KT  50 MPH
36H  15/1200Z 14.4N  45.9W   55 KT  65 MPH
48H  16/0000Z 15.0N  47.3W   70 KT  80 MPH
60H  16/1200Z 16.0N  48.7W   80 KT  90 MPH
72H  17/0000Z 17.2N  50.0W   90 KT 105 MPH
96H  18/0000Z 20.0N  52.4W  100 KT 115 MPH
120H  19/0000Z 23.0N  55.0W  100 KT 115 MPH

Forecaster Zelinsky