Tropical Storm Paulette Discussion Number  17
NWS National Hurricane Center Miami FL       AL172020
1100 PM AST Thu Sep 10 2020

Paulette has been fighting off intense vertical wind shear, which is 
analyzed by UW-CIMSS to be on the order of 35-40 kt out of the 
southwest. Deep convection with cold cloud tops of -70 to -80 
degrees C have persisted near and to the northeast of the center 
throughout the evening. A late arriving ASCAT overpass revealed that 
Paulette is stronger than previously analyzed, with believable wind 
vectors of 50-55 kt in the northeastern quadrant. There were some 
values even higher than these. However, the ASCAT ambiguities and 
satellite imagery suggest most of those are either rain contaminated 
or too close to the edge of the ASCAT pass to be trustworthy. 
Nonetheless, the other values indicate that the initial intensity is 
now at least 55 kt.

The SHIPS guidance suggests that the current shear over Paulette 
will begin to gradually decrease tomorrow and continue to decrease 
into the weekend. By late Saturday the guidance indicates the shear 
could fall to 10 kt or less. By that time, the cyclone is forecast 
to be traversing over waters with SSTs near 29 C. The only negative 
environmental factor could be some dry air in the vicinity of the 
system. However that same dry air has not seemed to have that much 
of an effect on Paulette as of late. With shear expected to remain 
fairly strong the next 24 h, no strengthening is anticipated during 
that time. After 24 h, Paulette should gradually intensify into 
early next week. The NHC intensity forecast for this advisory has 
been increased across the board. In the near term this change is due 
to the adjusted initial intensity. Beyond 24 h, the latest NHC 
forecast is close to a blend of the multi-model consensus values, 
including the HFIP corrected consensus and the Florida State 
Superensemble. 

Paulette is now moving northwest, or 305/09 kt. There is no change 
to the forecast track reasoning from the previous advisory. The  
forecast models are in good agreement between a generally northwest 
to west-northwestward motion over the next 3-4 days as the cyclone 
is steered around a subtropical ridge to its north. Around day 4, 
about the same time the system would be making its closest approach 
to Bermuda, a turn to the northeast is expected as the system 
rounds the western periphery of the ridge. The latest NHC track 
forecast is little changed from the previous one, and is near the 
tracks of the various consensus aids. It should be noted that there 
is sufficient spread in the track guidance such that it is too soon 
to know what types of impacts Paulette could have on Bermuda early 
next week.


Key Messages:

1.  Paulette is expected to approach Bermuda as a hurricane this
weekend and make its closest approach to the island on Monday and
Tuesday.  While the exact details of Paulette's track and intensity
near the island are not yet known, the risk of strong winds, storm
surge, and heavy rainfall on Bermuda continues to increase.

2.  Swells produced by Paulette are expected to affect portions of
the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda,
and the southeastern United States into the weekend.  These swells
could cause life-threatening surf and rip current conditions.


FORECAST POSITIONS AND MAX WINDS

INIT  11/0300Z 22.7N  50.9W   55 KT  65 MPH
12H  11/1200Z 23.4N  52.4W   55 KT  65 MPH
24H  12/0000Z 24.6N  54.1W   55 KT  65 MPH
36H  12/1200Z 26.1N  55.8W   60 KT  70 MPH
48H  13/0000Z 27.6N  57.6W   65 KT  75 MPH
60H  13/1200Z 28.9N  59.9W   70 KT  80 MPH
72H  14/0000Z 30.0N  62.3W   80 KT  90 MPH
96H  15/0000Z 32.6N  65.0W   85 KT 100 MPH
120H  16/0000Z 35.0N  62.5W   90 KT 105 MPH

$$
Forecaster Latto