ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM
 
Hurricane Paulette Discussion Number  27
NWS National Hurricane Center Miami FL       AL172020
1100 AM AST Sun Sep 13 2020
 
An Air Force Hurricane Hunter aircraft investigating Paulette this
morning found peak 700-mb flight-level winds of 92 kt, which reduces
to around 75 kt at the surface. However, around that same time the
peak winds measured by the SFMR instrument on board the aircraft
were only 58 kt. It is possible that the stronger winds suggested by
the flight-level values were not reaching the surface at that
location. Later on in the flight, the SFMR measured 64-kt winds in
the northwestern quadrant. Since there has been no notable change to
the structure of the hurricane since the aircraft was in the system
a few hours ago, the initial intensity is being held at 70 kt and is
a compromise of those two different peak values measured by the
aircraft.
 
Infrared satellite imagery has been showing some dry air intrusion 
over the eastern portion of the circulation, causing a break in the 
eyewall there over the past few hours. There is currently deep 
convection firing around the remainder of the eyewall, and therefore 
it is anticipated the dry air will be worked out of the system soon. 
Very low wind shear and warm waters will support strengthening over 
the next couple of days, and Paulette is expected to be a dangerous 
hurricane as it nears Bermuda Monday morning. The window for 
strengthening should continue for another 12-24 h after the cyclone 
passes Bermuda, and Paulette could become a major hurricane during 
that time. After 48 h, vertical wind shear is forecast to rapidly 
increase. After 72 h, Paulette is expected to cross the 26 degree C 
SST isotherm, and by 120 h those SSTs will be near 22 degrees C. 
The NHC forecast shows a weakening trend beginning after 48 h due to 
the negative environmental factors. By 120 h, the global models 
suggest that Paulette will have completed a transition to an 
extratropical cyclone.  The only change to the NHC intensity 
forecast from the previous advisory was a slight upward adjustment 
over the first few days due to the increase in strength found by 
the aircraft this morning. This forecast is in between the LGEM and 
HFIP corrected consensus, HCCA.
 
Paulette is now moving northwestward at 12 kt, to the southwest of a 
mid-level ridge. This motion should continue until just after the 
cyclone passes Bermuda. Later on Monday, the hurricane should turn 
north, then on Monday night 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 an approaching mid- to upper-level trough. Later on 
in the forecast period, a slower eastward motion is indicated once 
the aforementioned trough bypasses the cyclone. The latest NHC 
forecast track is little changed from the previous one through 48 h 
and lies in the middle of the latest global and regional track 
model guidance. Beyond 48 h, the NHC forecast is a little faster 
than the previous one, and lies near the tightly clustered consensus 
track guidance. On the forecast track, tropical storm conditions 
should reach Bermuda by this evening, 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  13/1500Z 29.9N  61.9W   70 KT  80 MPH
 12H  14/0000Z 30.9N  63.6W   80 KT  90 MPH
 24H  14/1200Z 32.8N  64.8W   90 KT 105 MPH
 36H  15/0000Z 35.0N  63.5W   95 KT 110 MPH
 48H  15/1200Z 37.0N  60.0W  100 KT 115 MPH
 60H  16/0000Z 39.1N  55.1W   95 KT 110 MPH
 72H  16/1200Z 41.4N  49.1W   85 KT 100 MPH
 96H  17/1200Z 43.9N  42.0W   65 KT  75 MPH
120H  18/1200Z 44.0N  36.6W   50 KT  60 MPH...POST-TROP/EXTRATROP
 
$$
Forecaster Latto
 
NNNN