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TROPICAL STORM HOWARD DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092016
800 AM PDT TUE AUG 02 2016
Howard's convective structure has not changed much since the
previous advisory with the low-level center located just inside the
southern edge of a ragged central dense overcast. The initial
intensity remains 50 kt, which is supported by a blend of CI
numbers from TAFB and SAB. Howard's center is now moving over sea
surface temperatures between 25-26C, and it should reach sub-24C
waters in about 24 hours. Vertical shear, on the other hand,
probably won't be too hostile for another 2 to 3 days. Therefore,
gradual weakening is forecast to begin in 12-24 hours and should
continue through the end of the forecast period. The intensity
guidance is holding Howard's intensity up a little longer compared
to previous cycles, and the updated NHC intensity forecast follows
this trend beginning at the 48-hour forecast period, lying close to
a blend of the SHIPS and LGEM models. At this point, it is
expected that vertical shear would cause Howard to become
post-tropical by 72 hours, which is also a little later than
indicated in previous advisories. It should be noted that the IVCN
intensity consensus is 5-10 kt higher than the official forecast on
days 3-5, so additional adjustments to the forecast intensity and
cyclone status may be necessary if it appears that Howard could hold
on as a tropical cyclone longer than currently anticipated.
The initial motion remains 295/13 kt. Howard is located near the
southwestern periphery of the subtropical ridge, which is expected
to build westward during the next 24 hours. As a result, the storm
should continue west-northwestward for the next 48 hours, followed
by a westward motion on days 3-5 once the cyclone becomes
post-tropical and is steered by the low-level trade winds. There
is very little spread among the track models, and the NHC track
forecast is essentially an update of the previous forecast.
FORECAST POSITIONS AND MAX WINDS
INIT 02/1500Z 18.8N 128.9W 50 KT 60 MPH
12H 03/0000Z 19.7N 130.9W 50 KT 60 MPH
24H 03/1200Z 20.8N 133.6W 45 KT 50 MPH
36H 04/0000Z 21.6N 136.4W 40 KT 45 MPH
48H 04/1200Z 22.2N 139.3W 40 KT 45 MPH
72H 05/1200Z 22.8N 145.0W 35 KT 40 MPH...POST-TROPICAL
96H 06/1200Z 23.0N 150.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 07/1200Z 23.0N 155.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
$$
Forecaster Berg
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