ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM HURRICANE DARBY DISCUSSION NUMBER 22 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016 800 PM PDT SAT JUL 16 2016 Darby has finally responded to the cooler SSTs, with a weakening in the central convection and the eye becoming less distinct. The current intensity is reduced to 90 kt which is a blend of Data-T and Current Intensity numbers. The cyclone is expected to traverse ocean waters of near 25 deg C, along the northern edge of the strong gradient of SST, for the next few days. Even though the shear is forecast to remain low for the next 2-3 days, the combination of cooler waters and a more stable air mass should result in continued weakening. Near the end of the forecast period, the SSTs under Darby will begin to warm a bit. By that time, however, increasing west-southwesterly shear should prevent restrengthening. Center fixes are in good agreement, which is not surprising given that an eye has been apparent, and the initial motion continues at 285/9 kt. A narrow mid-level subtropical ridge to the north of Darby is expected to remain in place for the next several days. This steering pattern should cause the tropical cyclone to move on a mainly westward heading for the next 4 days or so. By the end of the forecast period, the weakening system should be steered more by the low-level tradewind flow, and turn to a slightly south of westward heading. The official track forecast is very close to the previous one, and is a blend of the latest GFS and ECMWF solutions. A drifting buoy, ID 46906, near the southern eyewall of Darby, measured a pressure of 980.1 mb around 0200 UTC. FORECAST POSITIONS AND MAX WINDS INIT 17/0300Z 18.2N 125.8W 90 KT 105 MPH 12H 17/1200Z 18.4N 127.2W 85 KT 100 MPH 24H 18/0000Z 18.7N 129.1W 75 KT 85 MPH 36H 18/1200Z 18.9N 131.2W 65 KT 75 MPH 48H 19/0000Z 19.1N 133.2W 55 KT 65 MPH 72H 20/0000Z 19.8N 138.0W 45 KT 50 MPH 96H 21/0000Z 19.6N 142.5W 40 KT 45 MPH 120H 22/0000Z 18.5N 147.5W 35 KT 40 MPH $$ Forecaster Pasch NNNN