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Tropical Storm Paulette Discussion Number 21
NWS National Hurricane Center Miami FL AL172020
1100 PM AST Fri Sep 11 2020
Paulette remains sheared and asymmetric, with all its deep
convection north of its low-level center of circulation. Despite the
shear, ASCAT-B data that just arrived showed maximum winds near or
just over 55 kt. Since that instrument tends to under-sample the
maximum winds, the initial intensity is increased to 60 kt.
An upper-level low located to the west of Paulette is responsible
for the southerly shear currently affecting the cyclone. Global
model forecasts suggest that the shear will continue for another day
or so, and only slight strengthening is likely through that period.
By Sunday, the upper-level low will move farther southwest and the
tropical cyclone will encounter a very favorable upper-air pattern.
Paulette will likely strengthen further in response, possibly at a
fast rate. All of the intensity guidance indicates that Paulette
will be a hurricane when it nears Bermuda early Monday, and it could
approach major hurricane strength early next week. The NHC intensity
forecast has not changed since the last advisory. It is worth
mentioning that Paulette could experience a period of slow
development for the next 24 hours, followed by quick
intensification, rather than the more steady strengthening shown by
the NHC forecast. It is also important to note that the average NHC
intensity errors are around 10-15 kt at 48-72 h, the range at which
Paulette will likely be nearest to Bermuda.
Paulette has jogged slightly right of track during the past few
hours, but the overall NHC forecast track is not different from the
previous advisory. A building mid-level ridge to the north of
Paulette will likely steer the tropical storm generally
west-northwestward or northwestward for the next 2-3 days. The
cyclone is then expected to turn northeastward and accelerate in
that direction ahead of a mid-latitude trough. The model spread
remains relatively low, especially for the first few days.
Confidence is high that Paulette will move near Bermuda early
Monday, though it is still too soon to specify exactly how close it
will get. The NHC forecast is based heavily on the TVCA and HCCA
consensus aids and is not far from any of the global model forecast.
1. Paulette is expected to approach Bermuda as a hurricane on
Sunday and Monday. A prolonged period of strong winds, storm surge,
and heavy rainfall on Bermuda beginning Sunday night is becoming
more likely. A tropical storm watch is in effect and a hurricane
watch could be required for the island early Saturday.
2. Swells produced by Paulette are affecting portions of the
Leeward Islands and will continue to spread westward to 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 12/0300Z 25.8N 54.8W 60 KT 70 MPH
12H 12/1200Z 27.1N 56.5W 65 KT 75 MPH
24H 13/0000Z 28.5N 58.8W 65 KT 75 MPH
36H 13/1200Z 29.6N 61.2W 70 KT 80 MPH
48H 14/0000Z 30.7N 63.7W 80 KT 90 MPH
60H 14/1200Z 32.1N 65.1W 85 KT 100 MPH
72H 15/0000Z 33.8N 65.0W 90 KT 105 MPH
96H 16/0000Z 37.0N 60.0W 95 KT 110 MPH
120H 17/0000Z 40.0N 54.0W 85 KT 100 MPH