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#1017331 (Received by flhurricane at: 10:59 PM 16.Sep.2020)
TCDAT5

Hurricane Teddy Discussion Number 19
NWS National Hurricane Center Miami FL AL202020
1100 PM AST Wed Sep 16 2020

Teddy has been a perplexing hurricane thus far. The infrared
satellite presentation appears rather impressive, with the center
embedded beneath a Central Dense Overcast with cloud tops as cold
as -85 degrees Celsius. Despite the presentation, however, Dvorak
estimates from TAFB and SAB are a consensus T4.5/77 kt, and
objective estimates range between 70-75 kt. Teddy`s initial
intensity is therefore set just above these estimates at 80 kt.

A recent ASCAT pass indicated that Teddy`s center is a little
farther to the southwest than previously estimated. However, the
long-term motion remains toward the northwest (315/11 kt). The
track forecast remains straightforward the the next 3 days, with
the guidance in good agreement that a mid-tropospheric high over
the central Atlantic will drive the hurricane northwestward toward
the western Atlantic. There is a little more spread among the
track models on days 4 and 5, related to timing differences on
exactly where and how fast Teddy begins to recurve ahead of an
approaching mid-latitude trough coming from the northeastern United
States. The new NHC track forecast has been nudged westward during
the first 3 days to account for the initial position adjustment,
but otherwise it`s still close to the previous prediction even with
the increasing model spread on days 4 and 5.

An upper-level trough situated to the northwest of Teddy is causing
about 10-15 kt of deep-layer southwesterly shear over the
hurricane, and some model analyses suggest that there could be
stronger shear in a layer below the level of the upper-level
outflow. The deep-layer shear is expected to increase a bit during
the next day or so, but this should be offset by a favorable
thermodynamic environment, allowing for some intensification during
that time. The shear might relax by days 3 and 4, but then the
thermodynamic environment becomes a little less conducive for
strengthening. In particular, Teddy may move over the cold wake
of Hurricane Paulette, and the SHIPS guidance indicates that
relatively warm upper-level temperatures could be a negative
factor. All that said, the NHC intensity forecast lies near the
top end of the guidance envelope, showing Teddy peaking in
intensity in a couple of days and then only gradually weakening
through the end of the forecast period.


FORECAST POSITIONS AND MAX WINDS

INIT 17/0300Z 17.8N 51.5W 80 KT 90 MPH
12H 17/1200Z 18.9N 52.6W 85 KT 100 MPH
24H 18/0000Z 20.3N 54.1W 95 KT 110 MPH
36H 18/1200Z 21.8N 55.6W 100 KT 115 MPH
48H 19/0000Z 23.5N 57.1W 100 KT 115 MPH
60H 19/1200Z 25.3N 59.1W 95 KT 110 MPH
72H 20/0000Z 27.0N 61.1W 95 KT 110 MPH
96H 21/0000Z 30.0N 64.0W 90 KT 105 MPH
120H 22/0000Z 35.0N 64.0W 90 KT 105 MPH

$$
Forecaster Berg