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#872715 (Received by flhurricane at: 4:38 PM 22.Aug.2016) TCDAT1 TROPICAL DEPRESSION FIONA DISCUSSION NUMBER 24 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016 500 PM AST MON AUG 22 2016 A new burst of convection has developed near the center of Fiona during the past several hours. However, this increase was not significant enough to affect the subjective satellite intensity estimates, which remain at 30 kt. This is also in good agreement with earlier ASCAT data. The dynamical models forecast that the current westerly vertical shear will subside somewhat by 36-48 hours as Fiona moves under an upper-level trough into an area of easterly upper-level winds to the north of the trough. By 72 hours, the models forecast the cyclone or its remnants to encounter a second trough, which should produce another round of strong southwesterly shear. The intensity forecast is still based on the premise that the cyclone will not be able to respond to the brief period of more favorable conditions, and it calls for Fiona to gradually decay and become a remnant low in about 48 hours. This should be followed by the system weakening to a trough after 96 hours. The initial motion is 285/15. The guidance remains in good agreement on the forecast track through 72 hours, with Fiona moving west-northwestward to northwestward toward a weakness in the subtropical ridge. Beyond that time, the guidance diverges, with the ECMWF turning the remnants of the system northeastward while the GFS and UKMET show a westward turn. The new forecast track is again a compromise between these extremes in showing a slow north-northwestward motion. Overall, the track guidance has shifted westward since the previous advisory, and as a result the forecast track has also shifted a little to the west. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 25.1N 61.3W 30 KT 35 MPH 12H 23/0600Z 25.6N 63.1W 30 KT 35 MPH 24H 23/1800Z 26.5N 65.0W 30 KT 35 MPH 36H 24/0600Z 27.4N 66.7W 30 KT 35 MPH 48H 24/1800Z 28.3N 67.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 25/1800Z 30.5N 69.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 26/1800Z 31.5N 70.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 27/1800Z...DISSIPATED $$ Forecaster Beven |