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 387 
 WTNT44 KNHC 161434
 TCDAT4
 
 TROPICAL DEPRESSION NINE DISCUSSION NUMBER   1
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092015
 1100 AM AST WED SEP 16 2015
 
 Organized convection associated with the area of low pressure in the
 central tropical Atlantic has now increased to the point that the
 system is considered a tropical cyclone. The initial intensity is 25
 kt based on the latest Dvorak classifications and in agreement with
 earlier ASCAT wind data. Some southwesterly shear is already
 affecting the cyclone, with most of the convection displaced east
 and north of the estimated center position. The environment only
 becomes less favorable from this point forward, with the shear
 forecast to quickly increase in 12 to 24 hours and remain high
 through the remainder of the forecast period. In addition, the
 southwesterly flow aloft will bring dry mid- to upper-level air over
 the cyclone. As a result, only slight strengthening is shown in the
 NHC forecast following the trend of most of the intensity guidance.
 The cyclone is expected to weaken to a remnant low by 72 hours.
 After that time, the GFS and ECMWF models show the system weakening
 and perhaps opening up into a trough in about 5 days, so the
 official forecast shows dissipation at that time.
 
 The initial motion estimate is 340/07, as the depression is moving
 into a weakness in the Atlantic subtropical ridge. This north-
 northwestward to northwestward motion should continue for the next
 2 to 3 days, with a turn toward the west-northwest forecast by 96
 hours as the shallow cyclone comes under the steering influence of
 the low-level trade wind flow. The NHC track forecast is close to
 the middle of the guidance envelope and near a blend of the GFS and
 ECMWF forecasts.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  16/1500Z 15.0N  43.1W   25 KT  30 MPH
  12H  17/0000Z 16.0N  43.6W   25 KT  30 MPH
  24H  17/1200Z 17.3N  44.1W   30 KT  35 MPH
  36H  18/0000Z 18.5N  44.6W   30 KT  35 MPH
  48H  18/1200Z 19.7N  45.6W   25 KT  30 MPH
  72H  19/1200Z 22.0N  47.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
  96H  20/1200Z 24.0N  50.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 120H  21/1200Z...DISSIPATED
 
 $$
 Forecaster Brennan
 
 
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