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Hurricane Teddy Discussion Number  24
NWS National Hurricane Center Miami FL       AL202020
500 AM AST Fri Sep 18 2020
 
Teddy remains a powerful category 4 hurricane with a well-defined
eye and intense eyewall.  There have been occasional dry slots
that have eroded some of the convection in the eyewall and rain
bands, but these seem to be transient.  The satellite intensity
estimates currently range from 90 kt to 128 kt, and based on a
blend of that data, the initial intensity is set at 115 kt for this
advisory.
 
The hurricane is moving northwestward at 11 kt. Teddy is expected to 
continue moving northwestward at about the same forward speed during 
the next couple of days as it moves on the southwestern periphery of 
a subtropical high pressure system.  By the end of the weekend, when 
Teddy will likely be approaching Bermuda, a turn to the north or 
north-northeast is forecast to occur as a mid- to upper-level trough 
moves closer to the system.  However, the trough is expected to cut 
off, causing Teddy to turn slightly to the left early next week and 
approach Atlantic Canada in 4 to 5 days.  The models are in fairly 
good agreement, and only small changes were made to the previous NHC 
track prediction.

The major hurricane will likely maintain its intensity, or
fluctuate in strength, during the next day or so while it remains
in generally favorable conditions of low wind shear, warm waters,
and a fairly moist air mass.  However, the intensity models all
show a slow weakening trend after that likely due to Teddy tracking
over the cool SST wake left behind from Paulette and an increase in
shear by early next week.  Teddy is now forecast to transition to
a powerful extratropical cyclone by the end of the forecast
period based on the global model guidance.  The NHC intensity
forecast lies near the high end of the guidance envelope, in best
agreement with the LGEM dynamical-statistical model.
 
Teddy is producing a large area of high seas.  The maximum seas
estimated by TAFB near the core of the hurricane are around 40
feet.  Swells from Teddy are spreading far from the center, see
Key Messages below.
 
Key Messages:
 
1. Teddy is expected to approach Bermuda as a hurricane this
weekend and make its closest approach to the island late Sunday or
Monday. While the exact details of Teddy's track and intensity near
the island are not yet known, the risk of strong winds, storm surge,
and heavy rainfall on Bermuda is increasing.
 
2. Large swells produced by Teddy are expected to affect portions of
the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and
the southeastern United States during the next few days. These
swells could cause life-threatening surf and rip current conditions.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/0900Z 21.6N  55.4W  115 KT 130 MPH
 12H  18/1800Z 22.8N  56.5W  120 KT 140 MPH
 24H  19/0600Z 24.7N  58.1W  115 KT 130 MPH
 36H  19/1800Z 26.6N  59.9W  110 KT 125 MPH
 48H  20/0600Z 28.2N  61.6W  105 KT 120 MPH
 60H  20/1800Z 29.8N  62.7W  100 KT 115 MPH
 72H  21/0600Z 32.2N  62.8W   95 KT 110 MPH
 96H  22/0600Z 39.7N  61.9W   90 KT 105 MPH
120H  23/0600Z 46.0N  62.9W   65 KT  75 MPH...POST-TROP/EXTRATROP
 
$$
Forecaster Cangialosi
 
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