000 WTNT41 KNHC 301450 TCDAT1 TROPICAL STORM FRED DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015 1100 AM AST SUN AUG 30 2015 Visible satellite imagery indicates that convection associated with the tropical cyclone continues to organize. A curved band of convection now wraps almost completely around the center and recent images show that a small CDO feature has developed. An earlier WindSat microwave overpass also revealed a well-defined inner core. Dvorak T-numbers from TAFB and UW/CIMSS are around 3.0, and based on these the initial intensity is raised to 45 kt. The environment ahead of Fred appears conducive for strengthening during the next 24 to 36 hours. During that time, there will be sufficient mid-level moisture, the shear is expected to remain low, and the cyclone will be traversing sea surface temperatures of 27 to 28C. Therefore, steady strengthening is anticipated and the SHIPS and LGEM models bring Fred to hurricane status within 24 hours. Strengthening is also supported by the GFS and ECMWF models, which both show the cyclone deepening while it moves through the Cape Verde Islands. After 36 hours, lower sea surface temperatures, increasing southwesterly shear, and a more stable environment should cause weakening. Fred is moving northwestward at about 11 kt. The tropical storm is forecast to move northwestward toward a break in the subtropical ridge to the north of the Cape Verde Islands. In a couple of days, the ridge is forecast to build westward, which should cause Fred to turn west-northwestward. As Fred weakens and become a more shallow cyclone late in the period, a westward to west-northwestward motion is expected. The NHC track is near the consensus of the ECMWF and GFS models through 72 hours. Later in the period, the NHC forecast shows a weaker system moving more westward, and this track is along the southern edge of the guidance in best agreement with the ECMWF. Based on this track and intensity forecast, the Meteorological Service of the Cape Verde Islands has issued a Hurricane Warning for those islands. Please note that the track/cone graphic, an automatically generated product, does not have the capability of displaying warnings for the Cape Verde Islands. FORECAST POSITIONS AND MAX WINDS INIT 30/1500Z 13.4N 19.9W 45 KT 50 MPH 12H 31/0000Z 14.3N 21.3W 55 KT 65 MPH 24H 31/1200Z 15.7N 23.1W 65 KT 75 MPH 36H 01/0000Z 17.2N 25.1W 65 KT 75 MPH 48H 01/1200Z 18.3N 27.1W 65 KT 75 MPH 72H 02/1200Z 19.5N 31.5W 55 KT 65 MPH 96H 03/1200Z 20.5N 35.5W 45 KT 50 MPH 120H 04/1200Z 21.0N 39.5W 40 KT 45 MPH $$ Forecaster Brown