Issued at 1100 AM AST Fri Sep 14 2018 330 WTNT44 KNHC 141432TCDAT4Tropical Depression Isaac Discussion Number 28NWS National Hurricane Center Miami FL AL0920181100 AM AST Fri Sep 14 2018Deep convection has been increasing near the center of Isaac, butvisible imagery indicates that the circulation has becomemore elongated from northeast to southwest. It is possible thatIsaac is in the process of losing a well-defined center, but we willknow more about the wind structure in a few hours since the NOAAHurricane Hunter aircraft should be in the area. The initial windspeed is held at 30 kt.Vertical shear has decreased near Isaac, with some outflow in thewestern semicircle noted and consolidation of the convection.Still, this area of the eastern Caribbean isn't known as thegraveyard for nothing, and the system might just be too shallow anddisorganized to take advantage of the changing environment. Almostall of the dynamical models, save the UKMET, show the cyclone movingwestward to west-northwestward at a slower forward speed during thenext few days and degenerating into an open wave in the centralCaribbean Sea. This solution is also supported by fewer members ofthe GFS and ECMWF ensemble now maintaining a coherent system in thelong range. Little change is made to the previous track andintensity forecasts, and we will see what the aircraft finds thisafternoon and if the 1200 UTC model cycle maintains the dissipationtrend.FORECAST POSITIONS AND MAX WINDSINIT 14/1500Z 14.9N 67.3W 30 KT 35 MPH 12H 15/0000Z 15.0N 69.0W 30 KT 35 MPH 24H 15/1200Z 15.1N 71.3W 30 KT 35 MPH 36H 16/0000Z 15.2N 73.3W 25 KT 30 MPH 48H 16/1200Z 15.6N 75.3W 25 KT 30 MPH 72H 17/1200Z 17.0N 79.5W 25 KT 30 MPH 96H 18/1200Z...DISSIPATED$$Forecaster Blake

More...