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| #872634 (Received by flhurricane at: 10:47 AM 21.Aug.2016) TCDAT1 TROPICAL STORM FIONA DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016 1100 AM AST SUN AUG 21 2016 Strong westerly shear continues to take a toll on Fiona. After becoming devoid of convection overnight, new convective cells have developed around the small circulation, but there is not much organization to the thunderstorm activity. Besides, the clouds tops are already being sheared eastward by strong upper-level westerly flow. Satellite intensity estimates are gradually decreasing, so the initial wind speed has been lowered to 35 kt. Fiona will be moving through a hostile environment consisting of strong westerly shear and dry mid-level air during the next day or two. This should result in some additional weakening, and Fiona is forecast to become a tropical depression during the next 24 hours, and a remnant low in a couple of days. If the small circulation can survive the next 72 hours or so, environmental conditions could be conducive for regeneration late in the forecast period. The GFS and UKMET models maintain a weak low over the western Atlantic through day 5, while the ECMWF depicts an open trough of low pressure by 72 hours. The NHC forecast maintains continuity with the previous forecast, and shows dissipation around day 5. Fiona is moving west-northwestward or 295/14 kt. A low- to mid-level ridge over the central Atlantic should continue steering the cyclone west-northwestward during the next couple of days. Fiona will be nearing a break in the ridge over the western Atlantic by mid-week which should cause a northwestward turn and reduction in forward speed. The new NHC track forecast has been adjusted slightly southward and is located between the latest multi-model consensus and the previous NHC track prediction. FORECAST POSITIONS AND MAX WINDS INIT 21/1500Z 22.9N 53.3W 35 KT 40 MPH 12H 22/0000Z 23.6N 55.5W 35 KT 40 MPH 24H 22/1200Z 24.3N 58.1W 30 KT 35 MPH 36H 23/0000Z 25.0N 60.3W 30 KT 35 MPH 48H 23/1200Z 25.8N 62.2W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 24/1200Z 27.7N 65.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 25/1200Z 30.5N 67.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 26/1200Z...DISSIPATED $$ Forecaster Brown |
