ZCZC HFOTCDCP3 ALL TTAA00 PHFO DDHHMM TROPICAL STORM DARBY DISCUSSION NUMBER 52 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP052016 500 AM HST SUN JUL 24 2016 The center of Darby is difficult to find early this morning. The low level circulation of the system continues to reorganize after its encounter with the Big Island late Saturday. Even after the center emerged over the ocean west of the island Saturday evening, most of the circulation in the eastern semicircle was disrupted as it flowed around the volcanic peaks of nearly 14 thousand feet. A 1153z VIIRS image confirmed our earlier estimate of the center based on infrared satellite imagery and radar data. The satellite fix agencies estimates of current intensity ranged from 2.0/30 kt at JTWC and SAB to 2.5/36 kt at PHFO. The CIMSS ADT estimate was 2.1/31 kt. We are maintaining Darby as a 35 kt tropical storm for this advisory, since the system appears to be becoming better organized. Another flight by the 53rd Weather Reconnaissance Squadron is scheduled to fly into Darby a few hours after sunrise this morning to determine the location and intensity of the system as its circulation continues to churn over the warm ocean waters west of the Big Island. The initial motion is estimated to be 300/08 kt. This west-northwest motion is expected to continue this morning, followed be a turn to the northwest later today. This northwest motion will then likely continue during the next three days. The forecast models are showing this general motion due to the influence of a weakness developing in the mid-level ridge to the north of the tropical cyclone later today. This weakness is due to a deep-layer low that remains nearly stationary far north of the Hawaiian Islands. The updated track forecast is close to the previous and closely follows the latest multi-model consensus TVCN and the latest GFEX. The intensity forecast is maintaining Darby as a minimal tropical storm through 36 hours. The warm water temperatures and ample ocean heat content depicted in the most recent CIRA analyses south of the main Hawaiian Islands are likely sufficient to maintain a tropical storm. The latest SHIPS, as well as the IVCN consensus guidance, appear to indicate Darby may be able to remain a minimal tropical storm. However, within 48 hours, all of the guidance indicates steady weakening will occur, as increasing vertical wind shear and gradually cooling waters lie along the forecast track. The latest forecast again indicates weakening to a remnant low in 72 hours, with dissipation expected by the end of the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 24/1500Z 19.8N 157.3W 35 KT 40 MPH 12H 25/0000Z 20.7N 158.4W 35 KT 40 MPH 24H 25/1200Z 21.9N 159.7W 35 KT 40 MPH 36H 26/0000Z 23.4N 161.1W 35 KT 40 MPH 48H 26/1200Z 24.9N 162.6W 30 KT 35 MPH 72H 27/1200Z 28.0N 165.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 28/1200Z 32.0N 167.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 29/1200Z...DISSIPATED $$ Forecaster Houston NNNN