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Hurricane Humberto Discussion Number  23
NWS National Hurricane Center Miami FL       AL092019
500 AM AST Wed Sep 18 2019

Humberto's satellite presentation continues to be outstanding with
a large ragged eye and surrounded by deep convection. The eye of the
hurricane is very near NOAA Buoy 41048 and most likely will passing
over it by the time this advisory is being released. The pressure
from the buoy has been dropping fast and is now at 961 mb and the
sustained winds have reached 58 kt with gusts to 78 kt. Based on
satellite appearance and continuity, the initial intensity is kept
at 100 kt. Another Hurricane Hunter aircraft will check the cyclone
in a few hours.

Some fluctuations in strength due to a potential eyewall replacement
are possible during the next 12 to 24 hours or so. After that time
very strong southwesterly wind shear should impact the hurricane
resulting in weakening. In 72 hours or earlier, the global models
show the system merging with a frontal zone, so the NHC forecast
calls for extratropical transition by that time.  The official
intensity forecast follows the corrected consensus HCCA and is not
very different from the previous one.

Humberto is accelerating, and satellite fixes yield an initial
motion toward the east-northeast or 065 degrees at 14 kt.  Humberto
is located at the base of a strong mid-to upper-level trough, and
the hurricane will likely interact with this amplifying trough. This
should force Humberto to turn toward the northeast and north-
northeast at a faster forward speed in 24-36 hours. Later in the
forecast period, the track guidance indicates that Humberto will
turn back toward the east-northeast while becoming embedded within
the mid-latitude westerlies. The NHC track forecast is very similar
to the previous one and is in the middle of the guidance envelope.


Key Messages:

1. Hurricane conditions are expected in Bermuda tonight and Thursday
morning, with tropical-storm-force winds expected to begin later
today. Residents there should follow advice given by local
officials.

2.  Storm surge and dangerous breaking waves could cause coastal
flooding tonight and Thursday along the southern coast of Bermuda.

3. Swells will continue to affect the northwestern Bahamas and the
southeastern coast of the United States from east-central Florida to
North Carolina during the next couple of days, creating life-
threatening surf and rip current conditions.


FORECAST POSITIONS AND MAX WINDS

INIT  18/0900Z 31.7N  69.6W  100 KT 115 MPH
 12H  18/1800Z 32.7N  67.2W  105 KT 120 MPH
 24H  19/0600Z 34.8N  63.5W  100 KT 115 MPH
 36H  19/1800Z 37.5N  61.0W   85 KT 100 MPH
 48H  20/0600Z 40.0N  59.5W   65 KT  75 MPH
 72H  21/0600Z 43.0N  53.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  22/0600Z 45.5N  38.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  23/0600Z 52.1N  23.0W   45 KT  50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Avila

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