ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM DARBY DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016 900 PM MDT TUE JUL 12 2016 This evening's satellite presentation shows a considerable amount of improvement in Darby's cloud pattern. It appears as though the northeasterly shear, which was curtailing development, is decreasing. Deep convection has developed over the circulation center with -75C cloud tops, and a strong curved banding feature is evident in the western portion of the cyclone. Dvorak satellite intensity estimates are T3.5 from both agencies, and the initial intensity is increased to 55 kt for this advisory. Further strengthening is expected, and the majority of the intensity guidance indicates that Darby will become a hurricane in 12 hours. Models, particularly the LGEM, Decay SHIPS, and the FSU ensemble, are showing a stronger hurricane in 48-60 hours compared to earlier runs, and the forecast follows suit. Gradual weakening is forecast beyond day 3 as Darby traverses decreasing sea surface temperatures. Darby is moving a little to the left of the previous advisory, now 260/9 kt. The cyclone should continue on a general westward track during the next 48 hours south of a well established mid- to upper level ridge extending from Mexico. The GFDL and the GFS are still indicating a stronger break in the ridge beyond day 3 as a mid-latitude trough approaches the west coast of the United States. The other global models indicate the ridge maintaining strength through day 5. The official forecast basically splits the two solutions and sides with the multi-model consensus and the FSU superensemble. FORECAST POSITIONS AND MAX WINDS INIT 13/0300Z 15.4N 110.4W 55 KT 65 MPH 12H 13/1200Z 15.3N 111.8W 65 KT 75 MPH 24H 14/0000Z 15.3N 114.1W 75 KT 85 MPH 36H 14/1200Z 15.4N 116.4W 80 KT 90 MPH 48H 15/0000Z 15.5N 118.9W 85 KT 100 MPH 72H 16/0000Z 16.2N 123.3W 85 KT 100 MPH 96H 17/0000Z 16.8N 127.2W 75 KT 85 MPH 120H 18/0000Z 17.7N 131.1W 65 KT 75 MPH $$ Forecaster Roberts NNNN