Issued at 500 AM AST Fri Sep 14 2018 207 WTNT44 KNHC 140832TCDAT4Tropical Depression Isaac Discussion Number 27NWS National Hurricane Center Miami FL AL092018500 AM AST Fri Sep 14 2018Northwesterly shear continues to take a toll on Isaac. Although thesystem is still producing areas of deep convection, an ASCAToverpass that arrived shortly after the release of the previousadvisory, indicated that the circulation had become even lessdefined. The ASCAT data also showed that the winds are belowtropical storm strength, therefore the initial intensity has beenreduced to 30 kt.Moderate to strong northwesterly shear and dry mid-level air arelikely to cause additional weakening, and Isaac is forecast todegenerate into an open wave within the next several days, but thiscould occur much sooner if the current trends continue.When the system reaches the western Caribbean Sea the shear mayrelax somewhat and moisture levels are expected to be higher. Theseconditions could allow for regeneration of the system, but the ECMWFand GFS both show Issac weakening and moving over the westernCaribbean as an open wave, and the NHC forecast follows thisscenario.A low- to mid-level ridge over the southwestern Atlantic continuesto steer Isaac westward, and this general motion should continueuntil dissipation occur. The new track forecast is once againessentially an update of the previous advisory.FORECAST POSITIONS AND MAX WINDSINIT 14/0900Z 15.0N 65.5W 30 KT 35 MPH 12H 14/1800Z 15.1N 67.3W 30 KT 35 MPH 24H 15/0600Z 15.2N 69.7W 30 KT 35 MPH 36H 15/1800Z 15.2N 72.0W 25 KT 30 MPH 48H 16/0600Z 15.4N 73.8W 25 KT 30 MPH 72H 17/0600Z 16.4N 77.7W 25 KT 30 MPH 96H 18/0600Z...DISSIPATED$$Forecaster Brown

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