354 
WTNT43 KNHC 092032
TCDAT3

Hurricane Helene Discussion Number  10
NWS National Hurricane Center Miami FL       AL082018
500 PM AST Sun Sep 09 2018

Deep convection has increased in coverage and intensity over the
southern portion of the circulation, and microwave imagery suggests
that an inner core is beginning to develop.  Helene's maximum
winds are boosted to hurricane strength, 65 kt, based on Dvorak
Current Intensity numbers from SAB and TAFB.  The cyclone should
continue to traverse warm waters and be in a low-shear environment
for the next couple of days.  Therefore, additional intensification
is called for during the next 48 hours.  Afterwards, increasing
south-southwesterly shear should cause gradual weakening.  The
official intensity forecast is close to the model consensus, IVCN.

Helene is moving just north of due west, or 280/11 kt.  There are no
significant changes to the track forecast philosophy for this
advisory.  Helene should move generally west-northwestward along
the south side of a weak mid-level ridge for the next couple of
days.  After that, a mid-level trough digging along 40W-45W
longitude should induce a turn toward the northwest and eventually
north.  The official track forecast is very similar to the one from
the previous cycle through 72 hours, and is nudged a little to the
east after that time.  This is fairly close to the latest corrected
consensus guidance, HCCA.

FORECAST POSITIONS AND MAX WINDS

INIT  09/2100Z 13.4N  26.0W   65 KT  75 MPH
 12H  10/0600Z 13.9N  28.1W   75 KT  85 MPH
 24H  10/1800Z 14.5N  30.8W   85 KT 100 MPH
 36H  11/0600Z 15.2N  33.3W   90 KT 105 MPH
 48H  11/1800Z 15.9N  35.5W   90 KT 105 MPH
 72H  12/1800Z 18.0N  38.6W   80 KT  90 MPH
 96H  13/1800Z 21.5N  40.5W   65 KT  75 MPH
120H  14/1800Z 27.5N  41.5W   55 KT  65 MPH

$$
Forecaster Pasch