Official Discussion issued by the National Hurricane Center

Joyce (AL102018) DATA RELEASED: 9/17/2018 5:00:00 AM UTC

Copy of official data

Tropical Depression Joyce Discussion Number  19
NWS National Hurricane Center Miami FL       AL102018
500 AM AST Mon Sep 17 2018

A few convective cells have redeveloped to the northeast of the
estimated center, but this new convection is quickly being displaced
eastward by very strong vertical shear.  Global model guidance
indicates that strong westerly or northwesterly shear should
persist over Joyce for the next couple of days.  Thus, even though
the system is over marginally warm SSTs, the combination of strong
shear and very dry air in the mid-levels should cause the cyclone
to degenerate into a remnant low by 48 hours.  It would not be
surprising, however, to see Joyce degenerate even sooner than that.
The official intensity forecast is the same as the previous one and
close to the HWRF model guidance.

The circulation is a bit elongated, making the center somewhat
difficult to locate.  The initial motion is a rather uncertain
090/15 kt.  There has not been much change to the track forecast
reasoning.  Joyce is currently on the north side of a mid-level
high pressure area.  Over the next couple of days, the cyclone
should turn southeastward, southward, and then southwestward
around the eastern periphery of the high.  The NHC track forecast
is in good agreement with the latest dynamical model consensus, and
not too different from the previous official forecast.


INIT  17/0900Z 34.2N  29.0W   30 KT  35 MPH
12H  17/1800Z 33.7N  27.2W   30 KT  35 MPH
24H  18/0600Z 32.6N  26.2W   30 KT  35 MPH
36H  18/1800Z 31.5N  26.3W   25 KT  30 MPH
48H  19/0600Z 30.5N  27.3W   20 KT  25 MPH...POST-TROP/REMNT LOW
72H  20/0600Z 29.0N  30.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
96H  21/0600Z...DISSIPATED

Forecaster Pasch