000 WTPA42 PHFO 241438 TCDCP2 Hurricane Douglas Discussion Number 17 NWS Central Pacific Hurricane Center Honolulu HI EP082020 500 AM HST Fri Jul 24 2020 Douglas remains a powerful hurricane early this morning, although the satellite presentation has degraded quite a bit since last evening, with eye of the tropical cyclone now nearly completely cloud filled. The latest current intensity estimates from the satellite agencies came in with 5.5 (102 knots) from PHFO and SAB, 5.0 (90 knots) from JTWC, while ADT came in at 5.9 (112 knots). Taking a blend of the estimates above and accounting for recent satellite trends, the intensity with this advisory will be lowered to 105 knots. Douglas continues to move rapidly to the west-northwest, with an initial motion set at 295/16 knots. Hurricane Douglas recently moved over slightly cooler sea surface temperatures (SSTs) of around 78F, and this seems to have been enough to lead to the weakening seen in satellite imagery. Despite relatively low vertical wind shear values forecast to affect the tropical cyclone during the next couple days, SSTs will remain unfavorable for intensification. The official intensity forecast calls for steady weakening during the next couple days as Douglas nears Hawaii, with the cyclone expected to be a category 1 hurricane or strong tropical storm approaching the eastern end of the state late Saturday night or Sunday. Continued weakening is then forecast as Douglas tracks westward over or near the other main Hawaiian islands and west of the state early next week. Depending on the amount of interaction with the high terrain of the Big Island and Maui, the tropical cyclone could weaken faster than indicated in the official forecast, which follows a blend of the corrected consensus and statistical model guidance. Douglas is forecast to move rapidly off to the west-northwest during the next couple days toward a weakness in the sub-tropical ridge north of the Hawaiian islands. The subtropical ridge is forecast to strengthen north of the state over the weekend, and this should steer the tropical cyclone westward over or very near the Hawaiian Islands Sunday through Monday, before exiting to the west of the state. The official forecast continues to hug the southern end of the guidance envelope out of respect for the ECMWF, but if model trends continue, this track may need to be adjusted further northward in future advisory packages. Based on the latest intensity and track forecasts, Hurricane or Tropical Storm watches will likely be required for portions of the eastern end of the state (Big Island and the Maui County Islands) later today. Key Messages: 1. Douglas is expected to move near or over portions of the main Hawaiian Islands Sunday through Monday, and there is an increasing chance that strong winds, dangerous surf, and heavy rainfall could affect portions of the state beginning late Saturday night or Sunday. Interests on the Hawaiian Islands should continue to monitor the progress of Douglas and the official forecasts as they evolve during the next few days. FORECAST POSITIONS AND MAX WINDS INIT 24/1500Z 16.4N 141.9W 105 KT 120 MPH 12H 25/0000Z 17.4N 144.3W 95 KT 110 MPH 24H 25/1200Z 18.6N 147.5W 85 KT 100 MPH 36H 26/0000Z 19.6N 150.4W 75 KT 85 MPH 48H 26/1200Z 20.5N 153.4W 70 KT 80 MPH 60H 27/0000Z 21.1N 156.1W 65 KT 75 MPH 72H 27/1200Z 21.7N 158.8W 55 KT 65 MPH 96H 28/1200Z 22.5N 165.0W 50 KT 60 MPH 120H 29/1200Z 23.5N 171.5W 45 KT 50 MPH $$ Forecaster Jelsema