ZCZC MIATCDAT1 ALL TTAA00 KNHC DDHHMM TROPICAL STORM FRED DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015 1100 PM AST SUN AUG 30 2015 Fred has been maintaining strong convection in its CDO, and microwave data show a well-defined inner core. Subjective and objective Dvorak intensity estimates have not increased over the past several hours, however. The current intensity estimate is 60 kt, which is slightly above the most recent ADT values from UW-CIMSS. Upper-level outflow is well-defined over the tropical cyclone. The system should remain over marginally warm sea surface temperatures with moderate vertical shear for the next day or so, and sounding data from Sal in the Cape Verde Islands indicate that the Saharan Air Layer is not very prominent ahead of Fred. Given these conducive factors in the short term, the storm is likely to strengthen into a hurricane overnight. By 36 hours, vertical shear is forecast to increase significantly and a weakening trend should be underway by that time. Late in the forecast period, model guidance shows very dry low- to mid-level air affecting Fred with the shear remaining strong. This should result in the cyclone degenerating to a depression by the end of the period. The official intensity forecast is similar to the SHIPS and LGEM guidance and is the same as the previous one. Geostationary and microwave satellite imagery show that Fred continues on its northwestward trek. The track forecast reasoning is unchanged from the previous package. For the next few days, a weakening mid-level subtropical ridge over the eastern Atlantic should result in the tropical cyclone continuing northwestward with decreasing forward speed. Late in the forecast period, the ridge builds westward a bit and this, along with the weakening cyclone responding more to the lower-level flow, is likely to result in a turn to the left with time. The official track forecast is close to a consensus of the ECMWF and GFS solutions and lies on the southern side of the guidance suite. This is basically an update of the previous NHC track prediction. 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 31/0300Z 15.3N 22.4W 60 KT 70 MPH 12H 31/1200Z 16.2N 23.7W 70 KT 80 MPH 24H 01/0000Z 17.5N 25.5W 70 KT 80 MPH 36H 01/1200Z 18.8N 27.3W 65 KT 75 MPH 48H 02/0000Z 19.6N 29.0W 60 KT 70 MPH 72H 03/0000Z 20.8N 32.8W 50 KT 60 MPH 96H 04/0000Z 22.0N 36.5W 40 KT 45 MPH 120H 05/0000Z 23.0N 39.5W 30 KT 35 MPH $$ Forecaster Pasch NNNN