Official Discussion issued by the National Hurricane Center

Paulette (AL172020) DATA RELEASED: 9/12/2020 3:00:00 PM UTC

Copy of official data

Tropical Storm Paulette Discussion Number  23
NWS National Hurricane Center Miami FL       AL172020
1100 AM AST Sat Sep 12 2020

Paulette's structure is going through a bit of an evolution as the 
deep-layer shear backs from southwesterly to southeasterly.  Most 
of the deep convection had waned earlier this morning, but new 
convection is beginning to develop near the center as the cyclone 
reconstitutes itself.  For now, the initial intensity remains 60 
kt.  An overnight AMSR microwave pass showed that Paulette has 
well-defined low-level banding features, and this structure should 
allow the cyclone to strengthen as vertical shear falls below 10 kt 
during the next 12-24 hours.  Strengthening is anticipated to 
continue through day 3, and after that time, gradual weakening is 
possible due to increasing southwesterly shear.  The intensity 
guidance has been fairly stable for the past few forecast cycles, 
and no significant changes were required to this new NHC intensity 
forecast, which lies close to the HCCA model and just a bit above 
the intensity consensus.  Paulette is likely to be strengthening 
while it makes its closest approach to Bermuda in about 48 hours, 
and the GFS-based SHIPS and HWRF models each suggest that there is 
a possibility of it becoming a major hurricane in 72 hours.

Paulette is moving northwestward (310/13 kt), with a break in the 
subtropical ridge located due north of the storm.  The ridge may 
strengthen briefly over the next day or so, causing Paulette to 
move west-northwestward for a short time, but it should resume the 
northwestward motion by late Sunday.  After that time, an 
approaching longwave trough over the northeastern United States 
will erode the ridge eastward, causing Paulette to recurve sharply 
toward the north and then northeast between days 2 and 3.  The 
hurricane is then expected to accelerate east-northeastward toward 
the north Atlantic on days 4 and 5, embedded within the 
mid-latitude flow.  The track guidance is well clustered and has 
not shown any significant shifts over the past few forecast cycles. 
Therefore, the new NHC track forecast is similar to the previous 
one.


Key Messages:

1. Paulette is expected to approach Bermuda as a hurricane on
Sunday and be near the island Sunday night and Monday.  A prolonged 
period of strong winds, storm surge, and heavy rainfall is expected 
on Bermuda beginning late Sunday evening, and a hurricane warning 
has been issued for the island.  Preparations to protect life and 
property should be rushed to completion.

2. Swells produced by Paulette are affecting portions of the
Leeward Islands, the Greater Antilles, the Bahamas, and Bermuda, 
and are expected to spread westward to the east coast of the United 
States during the next day or two. These swells could cause 
life-threatening surf and rip current conditions.


FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 27.5N  57.2W   60 KT  70 MPH
12H  13/0000Z 28.5N  59.1W   65 KT  75 MPH
24H  13/1200Z 29.5N  61.4W   75 KT  85 MPH
36H  14/0000Z 30.8N  63.6W   80 KT  90 MPH
48H  14/1200Z 32.4N  64.8W   85 KT 100 MPH
60H  15/0000Z 34.2N  64.2W   90 KT 105 MPH
72H  15/1200Z 35.8N  61.5W   95 KT 110 MPH
96H  16/1200Z 39.0N  54.5W   90 KT 105 MPH
120H  17/1200Z 42.0N  47.0W   75 KT  85 MPH

$$
Forecaster Berg