[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 160237
TCDAT4

Hurricane Humberto Discussion Number  14
NWS National Hurricane Center Miami FL       AL092019
1100 PM EDT Sun Sep 15 2019

700 mb flight-level wind data from a NOAA P-3 Hurricane Hunter
aircraft investigating Humberto indicate that the system's intensity
is now 65 kt.  This is also supported by Dvorak classifications
from TAFB and SAB, and it makes the cyclone the third hurricane of
the 2019 Atlantic season.  Humberto's cloud pattern has continued to
gradually become better organized, with increasing coverage and
intensity of deep convection, and pronounced upper-level outflow
over the eastern semicircle of the circulation. The hurricane is
expected to traverse warm Gulf Stream waters for the next several
days, but the dynamical models forecast a significant increase in
southwesterly vertical shear through 72 hours.  In spite of the
latter unfavorable factor, the numerical guidance generally shows
intensification. This is likely at least partially due to some
baroclinic forcing caused by a strong mid-latitude trough to the
north and northeast of Humberto.  The official forecast is a blend
of the latest simple and corrected consensus models and is very
similar to the previous one.

Humberto continues to move very slowly and the latest aircraft and
satellite center fixes indicate that the motion is now
northeastward or 040/3 kt.  The hurricane has just rounded the
western periphery of a subtropical anticyclone and steering
currents are likely to remain weak for the next couple of days.  An
east-northeastward track with a very gradual increase in forward
speed is expected for much of the period while Humberto moves
between the subtropical high and stronger westerlies associated with
the trough to the north.  The new NHC track forecast is a little
slower than the previous one in 4-5 days, but not as slow as the
latest ECMWF and GFS global model runs.

Large swells from Humberto will affect portions of the northwestern
Bahamas and southeastern United States coast during the next few
days.  These swells are expected to produce dangerous surf
conditions and life-threatening rip currents.  See products issued
by your local weather office for additional information.


FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 29.4N  77.6W   65 KT  75 MPH
 12H  16/1200Z 29.8N  77.1W   70 KT  80 MPH
 24H  17/0000Z 30.1N  76.0W   75 KT  85 MPH
 36H  17/1200Z 30.5N  74.7W   80 KT  90 MPH
 48H  18/0000Z 30.8N  73.0W   85 KT 100 MPH
 72H  19/0000Z 31.8N  68.3W   95 KT 110 MPH
 96H  20/0000Z 35.0N  63.3W   80 KT  90 MPH
120H  21/0000Z 39.0N  60.0W   60 KT  70 MPH

$$
Forecaster Pasch
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