131
WTNT42 KNHC 132039
TCDAT2

Hurricane Paulette Discussion Number 28
NWS National Hurricane Center Miami FL AL172020
500 PM AST Sun Sep 13 2020

Paulette has recovered from the dry air intrusion that was eroding
the eastern eyewall this morning. A ring of deep convection with
cloud tops ranging from about -50 to -65 C now completely surrounds
a partially cleared eye. An Air Force Hurricane Hunter aircraft
investigating the hurricane earlier this afternoon measured peak
flight-level winds of 84 kt, which reduces to about 67 kt at the
surface. However, since that time there has been steady improvement
in the satellite presentation, and the latest Dvorak satellite
T-numbers from TAFB and SAB are now at 4.5, supporting increasing
the initial intensity to 75 kt for this advisory.

Paulette is expected to remain in a low-shear environment over warm
SSTs for the next 24-36 h, so gradual strengthening is likely during
that time. Around 48 h from now, vertical wind shear is forecast to
rapidly increase ahead of an approaching mid- upper level trough.
This should cause the cyclone to begin weakening. By 72 h, Paulette
is expected to be over waters less that 26 degrees C and should
remain over cooler waters for the remainder of the forecast period.
Around that same time, global models are indicating that the cyclone
will begin to interact with a frontal boundary associated with the aforementioned trough. This should induce a gradual transition of
Paulette to an extratropical cyclone, and that transition should be
completed by 120 h, if not sooner. The latest NHC intensity forecast
is little changed from the previous one and shows Paulette
continuing to strengthen as it passes near or over Bermuda early
Monday. The forecast also shows Paulette becoming a major hurricane
by Monday night, after the cyclone has moved away from Bermuda. This
intensity forecast is in good agreement with the HFIP corrected
consensus, HCCA.

Paulette is moving northwestward at 11 kt, to the southwest of a
mid-level ridge. There is no change to the forecast track reasoning.
This northwest motion should continue until just after the cyclone
passes Bermuda Monday morning. Later on Monday, the hurricane should
turn north, then northeastward, as it rounds the periphery of the
ridge. After turning northeastward, the cyclone is expected to
accelerate as it gets picked up in the mid-latitude flow ahead of
the approaching trough. Later on in the forecast period a slower
eastward motion is indicated once the trough bypasses the cyclone.
The latest NHC forecast was nudged only slightly to the left of the
previous one, and is in agreement with tightly clustered global and
regional track guidance. Tropical storm conditions should reach
Bermuda in the next couple of hours, with hurricane force winds
arriving there overnight.

Key Messages:

1. Paulette is expected to approach Bermuda as a hurricane today
and will be near the island tonight and Monday. A prolonged
period of strong winds, storm surge, and heavy rainfall is expected
on Bermuda beginning this evening, and a hurricane warning is in
effect 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, Bermuda, and
the east coast of the United States. These swells could cause
life-threatening surf and rip current conditions.


FORECAST POSITIONS AND MAX WINDS

INIT 13/2100Z 30.6N 63.1W 75 KT 85 MPH
12H 14/0600Z 31.8N 64.5W 85 KT 100 MPH
24H 14/1800Z 33.9N 64.8W 95 KT 110 MPH
36H 15/0600Z 36.1N 62.4W 100 KT 115 MPH
48H 15/1800Z 38.1N 57.8W 100 KT 115 MPH
60H 16/0600Z 40.3N 52.6W 95 KT 110 MPH
72H 16/1800Z 42.4N 47.4W 80 KT 90 MPH
96H 17/1800Z 45.5N 38.7W 60 KT 70 MPH
120H 18/1800Z 44.4N 34.1W 45 KT 50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Latto
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