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TROPICAL DEPRESSION IDA DISCUSSION NUMBER  25
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL102015
1100 AM AST THU SEP 24 2015

There has been no significant change in the satellite presentation
of the cyclone. Ida is a sheared system and consists of a broad
circulation with a cyclonically curved convective band around the
eastern side.  Based on a recent ASCAT pass the initial intenisty
has been lowered to 30 kt. The hostile shear environment will likely
continue today, but both the operational SHIPS and the experimental
SHIPS based on ECMWF fields lower the shear allowing for some
restrengthening. On this basis, the NHC forecast calls for little
change in intensity during the next day or two, and some minor
increase of the winds after that time.

Ida has begun to move toward the north-northeast at 4 kt. The
cyclone will become completely detached from the mid-level trough in
about 12 to 24 hours, and will be slowly steered toward the north
and north-northwest by the flow surrounding a developing subtropical
ridge. After that time, a stronger ridge will force Ida to turn
westward with some increase in forward speed. Track guidance is very
consistent with this westward turn, however, by then, the status of
Ida is highly uncertain. Ida could still be a tropical cyclone as
indicated in the NHC forecast or it will be degenerating into a
trough as indicated by the GFS.


FORECAST POSITIONS AND MAX WINDS

INIT  24/1500Z 20.2N  44.9W   30 KT  35 MPH
 12H  25/0000Z 20.8N  44.7W   30 KT  35 MPH
 24H  25/1200Z 21.5N  45.0W   30 KT  35 MPH
 36H  26/0000Z 22.5N  45.5W   30 KT  35 MPH
 48H  26/1200Z 23.5N  46.5W   35 KT  40 MPH
 72H  27/1200Z 24.5N  48.0W   40 KT  45 MPH
 96H  28/1200Z 24.5N  50.0W   40 KT  45 MPH
120H  29/1200Z 24.0N  52.0W   40 KT  45 MPH

$$
Forecaster Avila

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