057 WTPA43 PHFO 162041 TCDCP3 Tropical Storm Greg Discussion Number 12 NWS Central Pacific Hurricane Center Honolulu HI EP082023 1100 AM HST Wed Aug 16 2023 Greg continues to be affected by southeasterly vertical wind shear, and pulsing deep convection remains largely displaced to the north and west of a partially exposed low-level circulation center. JTWC and SAB came in with a current intensity of 2.5/35 kt, and HFO estimated 3.5/55 kt, while CIMSS ADT was down at 37 kt. Given that the satellite presentation is slightly degraded, a blend of these inputs supports dropping the official intensity to 40 kt with this advisory. Greg remains on a relatively steady forward motion that is slightly north of due west, 280/12 kt. A low- to mid-level ridge far to the north will keep the tropical cyclone moving along a general westward track through the next 36 hours, causing Greg to pass well south of Hawaii. A turn toward the west-southwest is forecast on Friday as the weakening tropical cyclone is steered by a deepening ridge to the north. The official forecast track was changed little from the prior advisory and lies near TVCE in the middle of a tightly clustered guidance envelope. The intensity forecast is more challenging. Relatively light, southerly vertical wind shear has been rather disruptive, leading to the pulsing deep convection near the center of Greg. Conditions will change little during the next 24 hours or so, and the official forecast indicates no change in intensity, which is higher than all guidance. Beyond 24 hours, guidance continues to split into two camps. The dynamical guidance shows steady weakening as a deep, strengthening ridge to the north imparts westerly to northwesterly vertical wind shear, while the statistical guidance continues to suggest some intensification. Given the tropical cyclone's inability to resist the current shear environment, the official forecast follows the steady weakening trend at the higher end of the dynamical guidance envelope beyond 24 hours, and Greg is expected to become a post-tropical remnant low this weekend. FORECAST POSITIONS AND MAX WINDS INIT 16/2100Z 11.9N 152.5W 40 KT 45 MPH 12H 17/0600Z 12.1N 154.3W 40 KT 45 MPH 24H 17/1800Z 12.2N 156.6W 40 KT 45 MPH 36H 18/0600Z 12.1N 159.1W 35 KT 40 MPH 48H 18/1800Z 11.8N 161.7W 35 KT 40 MPH 60H 19/0600Z 11.3N 164.4W 30 KT 35 MPH 72H 19/1800Z 11.0N 167.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 20/1800Z 10.1N 171.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 21/1800Z...DISSIPATED $$ Forecaster Wroe