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#800092 (Received by flhurricane at: 4:38 PM 01.Sep.2015) TCDAT1 TROPICAL STORM FRED DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015 500 PM AST TUE SEP 01 2015 Fred's weakening appears to have ceased for the moment. Deep convection developed just north of the center since the previous advisory and the overall organization of the tropical cyclone has changed little during the day. A blend of the various Dvorak T-numbers and the earlier ASCAT data support maintaining an initial intensity of 45 kt. The intensity forecast reasoning remains unchanged from the previous forecast. Fred will be moving into an area of increasing southwesterly shear and a less conducive thermodynamic environment. This should cause the tropical cyclone to gradually weaken during the next several days, and Fred is expected to become a tropical depression in about 36 hours and degenerate to a remnant low in 2 to 3 days. The initial motion estimate is 300/10 kt. Fred should continue moving west-northwestward to the south of a deep-layer ridge over the eastern Atlantic during the next 2 to 3 days. The global models predict that the western portion of the ridge will weaken after 72 hours when a trough deepens over the central Atlantic. After this occurs, the remnant low should turn northwestward and northward in the low-level southeasterly flow. The model guidance has shifted significantly westward this cycle, with most of the models showing a weaker Fred moving more westward. The NHC forecast has been adjusted accordingly, however it lies to the north of the model consensus after 36 hours to maintain some continuity from the previous advisory. FORECAST POSITIONS AND MAX WINDS INIT 01/2100Z 18.8N 28.1W 45 KT 50 MPH 12H 02/0600Z 19.4N 29.4W 40 KT 45 MPH 24H 02/1800Z 20.0N 31.0W 35 KT 40 MPH 36H 03/0600Z 20.6N 32.5W 30 KT 35 MPH 48H 03/1800Z 21.3N 34.1W 30 KT 35 MPH 72H 04/1800Z 22.0N 37.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 05/1800Z 23.0N 40.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 06/1800Z 25.0N 42.0W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Brown |