000 WTPZ45 KNHC 130839 TCDEP5 Hurricane Darby Discussion Number 16 NWS National Hurricane Center Miami FL EP052022 1100 PM HST Tue Jul 12 2022 Darby has been gradually weakening over ocean surface temperatures near or just below 26 degrees Celsius. Satellite imagery show the eye has filled in and the extent of the cold cloud tops has shrunk. A scatterometer pass at 0545 UTC over the inner core revealed a very small storm. Dvorak CI-numbers from SAB and TAFB estimated the intensity of Darby at 90 kt. However, objective satellite intensity estimates ranged between 82 to 87 kt from UW/CIMSS ADT and SATCON and have been decreasing. The initial intensity has been lowered to 85 kt to represent a blend of all of these estimates and the current trend. The less conducive environmental conditions appear to be taking a toll on this tiny storm. Based on satellite imagery, Darby is completely surrounded by a dry mid-level air mass. The hurricane is also expected to remain over marginal sea surface temperatures and these two factors should continue to gradually weaken Darby over the next day or so. The vertical wind shear is predicted to increase quickly in a couple of days which should rapidly weaken Darby into a remnant low in about 72 hours. The official intensity forecast is shifted slightly lower than the previous advisory and below much of the consensus guidance. Given the small size of this cyclone, it would not be surprising if Darby weakened even faster than indicated here. Darby continues to move westward at about 14 kt while it is steered by a subtropical ridge to its north. Over the next 24 hours, the system is expected to reach a slight weakness in the ridge and turn west-northwestward temporarily. While Darby weakens further it will likely turn west once again and follow the low-level steering flow until it dissipates. The NHC track forecast is slightly south of the previous prediction beyond 36 hours and close to the model consensus aids. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 14.7N 133.9W 85 KT 100 MPH 12H 13/1800Z 15.0N 136.0W 80 KT 90 MPH 24H 14/0600Z 15.7N 138.6W 70 KT 80 MPH 36H 14/1800Z 16.2N 141.2W 60 KT 70 MPH 48H 15/0600Z 16.5N 143.6W 50 KT 60 MPH 60H 15/1800Z 16.6N 146.4W 40 KT 45 MPH 72H 16/0600Z 16.5N 149.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 17/0600Z 16.3N 156.2W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 18/0600Z...DISSIPATED $$ Forecaster Pasch/Bucci