000
WTNT42 KNHC 090237
TCDAT2

TROPICAL DEPRESSION GRACE DISCUSSION NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072015
1100 PM AST TUE SEP 08 2015

Grace continues to produce disorganized bursts of convection near
and south of the low-level center, and a recent ASCAT-B overpass
shows that the cyclone still has a closed circulation.  The initial
intensity remains 30 kt based on satellite intensity estimates from
TAFB and SAB, although the scatterometer data suggests this could be
a little generous.  The cyclone is likely to produce intermittent
bursts of convection over the next day or two.  However, it is
moving through an environment of dry mid-level air and westerly
vertical shear that is forecast to increase to 25-30 kt by 72
hours - a combination that should cause further weakening. The new
intensity forecast is unchanged from the previous forecast, calling
for Grace to become a remnant low in about 36 hours and to dissipate
completely after 72 hours. There is a possibility, supported by most
of the global models, that Grace could degenerate into an open wave
before 72 hours.

The initial motion remains 275/16 kt.  A low- to mid-level
subtropical ridge should continue to steer Grace or its remnants
quickly westward until the system dissipates.  The new forecast
track is again an update of the previous track and lies near the
center of the tightly clustered guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT  09/0300Z 14.6N  45.8W   30 KT  35 MPH
 12H  09/1200Z 14.9N  48.3W   30 KT  35 MPH
 24H  10/0000Z 15.3N  51.8W   30 KT  35 MPH
 36H  10/1200Z 15.8N  55.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  11/0000Z 16.3N  58.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  12/0000Z 17.0N  65.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  13/0000Z...DISSIPATED

$$
Forecaster Beven