Hurricane Teddy Discussion Number  20
NWS National Hurricane Center Miami FL       AL202020
500 AM AST Thu Sep 17 2020

Several passive microwave overpasses have revealed that Teddy has 
developed a 25-nmi-wide closed eye, while GOES-16 infrared 
satellite data shows significant cooling of the cloud tops 
surrounding a ragged eye feature. As a result, satellite intensity 
estimates have increased, thus Teddy's intensity has been increased 
to 90 kt based on a Dvorak classification of T5.0/90 kt from SAB 
and a recent UW-CIMSS adjusted-ADT value of T5.7/105 kt.

The initial motion estimate based on the microwave satellite fixes 
is 305/10 kt. As described in previous discussions, the track 
forecast and reasoning both remain straightforward and unchanged for 
the next 72 h. The latest NHC model guidance is in excellent 
agreement that a deep-layer ridge situated over the central Atlantic 
will force Teddy on a northwestward track toward the western 
Atlantic.  There is a little less divergence among the models on 
days 4 and 5 then on previous runs, and this difference remains 
related timing differences on where and how fast the hurricane 
begins to recurve ahead of an approaching mid-latitude trough and 
frontal system moving off the coast of the eastern United States in 
about 3 days.  The new NHC track forecast is close to the previous 
advisory track now that it appears that the models have settled 
down, and lies close to the consensus models TVCA, HCCA, and FSSE.

The overall environmental conditions appear to be conducive for 
Teddy to continue to at least gradually strengthen for the next 
36-48 hours.  However, with sea-surface temperatures expected to be 
near 30 deg C in 48-72 hours when the vertical shear is going to be 
near zero, the intensity forecast at that time could be too low. For 
now, the official intensity forecast lies near the upper end of the 
guidance envelope, and shows Teddy's intensity leveling off after 36 
hours due to the very dry environment that the hurricane will be 
moving through, which could disrupt the inner-core convective 
pattern and eye feature.

FORECAST POSITIONS AND MAX WINDS

INIT  17/0900Z 18.3N  52.3W   90 KT 105 MPH
12H  17/1800Z 19.5N  53.5W   90 KT 105 MPH
24H  18/0600Z 20.9N  54.9W  100 KT 115 MPH
36H  18/1800Z 22.5N  56.5W  105 KT 120 MPH
48H  19/0600Z 24.3N  58.2W  105 KT 120 MPH
60H  19/1800Z 26.1N  60.2W  100 KT 115 MPH
72H  20/0600Z 27.6N  62.0W  100 KT 115 MPH
96H  21/0600Z 30.7N  64.0W   95 KT 110 MPH
120H  22/0600Z 36.0N  62.9W   90 KT 105 MPH

$$
Forecaster Stewart