Tropical Storm TEDDY Advisory Thu Sep 17

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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