Hurricane Teddy Discussion Number  25
NWS National Hurricane Center Miami FL       AL202020
1100 AM AST Fri Sep 18 2020

There was little change to the structure of Teddy since early this 
morning up until the past hour or so, when the eye began to 
fill in slightly while the cloud tops over the southern portion of 
the circulation warmed a bit. However, new convection with very 
cold cloud tops near -80 degrees C have developed recently over 
the northwestern quadrant, so the cyclone could just be undergoing 
a temporary intensity fluctuation that typically occurs in powerful 
hurricanes. The latest Dvorak intensity estimates range from 102 kt 
to 116 kt, and the initial intensity is being held at 115 kt for 
this advisory. There will be staggered NOAA and U.S. Air Force 
Reserve Hunter aircraft investigating Teddy starting this morning 
and continuing into the late afternoon, so they will soon be able to 
provide updated details on the latest structure, size, and intensity 
of the hurricane.

The major hurricane continues to move northwestward, now at 10 kt. 
Teddy is expected to remain on that general course during the next 
couple of days as it moves on the southwestern periphery of a 
mid-level ridge.  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 off the 
northeastern U.S. coast. Early next week, the trough is expected to 
cut off, causing Teddy to turn slightly to the left and approach 
Nova Scotia in 4 to 5 days.  The models continue to be in good 
agreement on this scenario, and only small adjustments were made to 
the previous forecast track.

Teddy will likely fluctuate in intensity over the next day or so 
while it remains in favorable conditions of low wind shear, warm 
waters, and a fairly moist air mass.  By late this weekend, the 
hurricane is forecast to traverse over cooler waters churned up by 
Paulette last week. This should cause a weakening trend to begin. 
By Monday night, vertical wind shear is expected to drastically 
increase ahead of the approaching mid-latitude trough. This should 
not only weaken Teddy, but begin its transition to a large 
extratropical cyclone, and that transition should be completed 
before the end of the forecast period. The latest NHC intensity 
forecast is near the HFIP corrected consensus aid HCCA through 36 
h, and then trends toward the SHIPS and LGEM intensity guidance 
thereafter.

Teddy is producing a large area of high seas.  The latest maximum 
seas estimated by TAFB near the core of the hurricane are near 45 
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, there is a risk strong winds, storm 
surge, and heavy rainfall on Bermuda, and watches may be issued 
later today or tonight. 

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  18/1500Z 22.1N  56.1W  115 KT 130 MPH
12H  19/0000Z 23.3N  57.2W  115 KT 130 MPH
24H  19/1200Z 25.2N  58.9W  115 KT 130 MPH
36H  20/0000Z 27.1N  60.7W  110 KT 125 MPH
48H  20/1200Z 28.7N  62.2W  105 KT 120 MPH
60H  21/0000Z 30.7N  62.7W  100 KT 115 MPH
72H  21/1200Z 33.7N  62.2W   95 KT 110 MPH
96H  22/1200Z 41.4N  62.5W   80 KT  90 MPH
120H  23/1200Z 46.8N  62.0W   55 KT  65 MPH...POST-TROP/EXTRATROP

$$
Forecaster Latto