Official Discussion issued by the National Hurricane Center

Joyce (AL102018) DATA RELEASED: 9/16/2018 5:00:00 AM UTC

Copy of official data

Tropical Storm Joyce Discussion Number  15
NWS National Hurricane Center Miami FL       AL102018
500 AM AST Sun Sep 16 2018

What's left of the Joyce's associated deep convection is now
displaced about 80 miles to the north-northeast of the elongated
surface circulation.  There still may be some 35 kt winds in a
small area of deep convection where the coldest cloud tops (-65C)
are observed, therefore, the initial intensity is held at 35 kt for
this advisory.

There is no change to the intensity forecast philosophy.  The
surrounding environment is forecast to remains quite unfavorable
during the next 24 hours, although the warm 27C oceanic temperatures
could slightly counteract the negative effects of the harsh vertical
shear pattern.  Afterward, decreasing sea surface temperatures, a
more stable thermodynamic air mass, along with the stiff shear, is
forecast to induce gradual weakening and, ultimately, dissipation in
4 days.

The initial motion is estimated to be east-northeastward, or 075/15
kt.  The cyclone is embedded within the same mid-tropospheric
steering flow as Tropical Storm Helene, and Joyce should move
east-northeastward to eastward today.  Through day 3, Joyce should
turn southeastward to south-southwestward around the eastern
periphery of a subtropical ridge to its west as a vertically
shallow system.  The NHC forecast is similar to the previous
advisory, and is based on the better-performing consensus aids.


INIT  16/0900Z 34.0N  36.1W   35 KT  40 MPH
12H  16/1800Z 34.5N  33.4W   30 KT  35 MPH
24H  17/0600Z 34.6N  30.1W   30 KT  35 MPH
36H  17/1800Z 34.1N  27.8W   30 KT  35 MPH
48H  18/0600Z 32.9N  26.8W   25 KT  30 MPH
72H  19/0600Z 30.7N  28.5W   25 KT  30 MPH
96H  20/0600Z...DISSIPATED

Forecaster Roberts