ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM HURRICANE DARBY DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052016 300 PM MDT WED JUL 13 2016 Darby is taking on a different shape as the vertical shear gradually decreases. Convective bursts with overshooting tops have been occurring near the center, and a broken band of convection wraps around the southern and western part of the circulation. Subjective and objective Dvorak estimates are unanimously T4.0, and Darby is therefore being upgraded to a 65-kt hurricane. Ocean temperatures near Darby are between 28-29 degrees Celsius, and even though SSTs decrease some out ahead of the hurricane, microwave data suggest that the ocean is warming up after the passages of Blas and Celia. Vertical shear is also expected to be low during the next few days, and Darby should continue strengthening for the next 36-48 hours. The NHC intensity forecast is not too different from the previous forecast, and it is near or just above the upper bound of the intensity guidance. The latest fixes indicate that Darby is beginning to gain latitude again, and the 12-hour average motion is 270/10 kt. Mid-level ridging to the north of the hurricane is expected to change very little over the next five days, and Darby should therefore maintain a consistent westward track through the forecast period. The track guidance has shifted a little to the north on this cycle, and there is very little cross-track difference noted among the models. However, there are some along-track speed differences, with the ECMWF showing a faster motion due to a stronger depiction of the mid-level ridge. The updated NHC track forecast has been nudged northward and is a little faster than the previous forecast, lying close to a consensus of the GFS and ECMWF. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 15.4N 113.6W 65 KT 75 MPH 12H 14/0600Z 15.6N 115.3W 75 KT 85 MPH 24H 14/1800Z 16.0N 117.8W 85 KT 100 MPH 36H 15/0600Z 16.4N 120.3W 90 KT 105 MPH 48H 15/1800Z 16.8N 122.7W 90 KT 105 MPH 72H 16/1800Z 17.3N 126.7W 75 KT 85 MPH 96H 17/1800Z 17.8N 130.7W 65 KT 75 MPH 120H 18/1800Z 18.5N 135.0W 55 KT 65 MPH $$ Forecaster Berg NNNN