000
WTNT42 KNHC 080839
TCDAT2

TROPICAL STORM GRACE DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072015
500 AM AST TUE SEP 08 2015

The deep convection that developed during the evening hours has
expanded in coverage overnight, but very little banding or overall
organization of the thunderstorm activity exists.  The initial wind
speed remains 35 kt, which is supported by a TAFB subjective Dvorak
intensity estimate and a UW/CIMSS ADT current intensity number.  The
intensity forecast reasoning remains unchanged from the previous
advisory.  Increasing southwesterly to westerly vertical wind shear
and dry mid-level air along the forecast track should cause Grace to
weaken during the next few days.  Grace is forecast to weaken to a
tropical depression later today, and become a remnant low within
the next couple of days.  The system is expected to degenerate to a
trough by the time it reaches the eastern Caribbean.  Given the fast
motion of the system and the expected hostile conditions, this could
occur much sooner than shown in the official forecast.

The initial motion estimate remains 275/17 kt. Grace or its remnant
is forecast to continue moving quickly westward to the south of a
low- to mid-level ridge that is over the central Atlantic.  The
model guidance is again tightly clustered and the NHC forecast is
essentially an update of the previous track.

FORECAST POSITIONS AND MAX WINDS

INIT  08/0900Z 14.1N  41.0W   35 KT  40 MPH
 12H  08/1800Z 14.2N  43.7W   30 KT  35 MPH
 24H  09/0600Z 14.5N  47.2W   30 KT  35 MPH
 36H  09/1800Z 14.9N  50.6W   30 KT  35 MPH
 48H  10/0600Z 15.3N  54.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  11/0600Z 16.3N  60.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  12/0600Z...DISSIPATED

$$
Forecaster Brown