000 WTPA41 PHFO 230858 TCDCP1 Tropical Storm Hone Discussion Number 4 NWS Central Pacific Hurricane Center Honolulu HI CP012024 1100 PM HST Thu Aug 22 2024 The satellite appearance of Hone has degraded since the previous advisory package, with deep convection now limited to near the low level circulation center. The latest subjective Dvorak intensity estimates came in at 2.5 for PHFO and SAB, and 2.0 for JTWC. The objective intensity estimates ADT/AiDT from UW-CIMSS came in at 37 knots each. A recent and timely ASCAT MetOp-B pass sampled a large portion of the eastern semicircle of Hone, with a large swath of 35 to 40 knot winds. As a result, the initial intensity of Hone has been increased slightly to 40 knots with this advisory. Air Force Reserve Reconnaissance Aircraft will give us a better idea of the intensity, structure, and size of Hone Friday morning. The initial motion for this advisory is set at 280/12 knots. This general motion is expected to continue during the next several days as Hone is steered by a large subtropical ridge to the north. A decrease in forward speed and a slight turn towards the west-northwest is expected during the first half of next week as a weakness develops in the subtropical ridge north of the system. The official forecast track lies nearly on top of the track from the previous advisory, and closely follows the tightly clustered consensus guidance. Environmental conditions will change little during the next few days. Hone will remain in an environment characterized by low to moderate vertical wind shear, sea surface temperatures around 26 to 27C, and sufficient deep layer moisture. This is expected to support gradual strengthening of the system as it moves in a general westward direction during the next couple of days. It appears that there is a window for further intensification Sunday through Tuesday as the system tracks south of the Hawaiian Islands. Hone will be moving into an area with sea surface temperatures of 27C and higher ocean heat content, while the westerly vertical wind shear remains at light to moderate levels. This could allow Hone to reach Hurricane strength and the current official forecast reflects this. Beyond day 4, westerly vertical wind shear increases sharply to between 30 and 35 knots, and some drier mid-level air appears to begin entraining into the system. This should result in a weakening trend by day 5. The intensity forecast is close to the intensity consensus during the next several days, and is roughly a blend of the statistical and dynamical consensus guidance from days 3 through 5. KEY MESSAGES: 1. There is the potential for excessive rainfall and flash flooding on portions of the Big Island starting later Saturday, continuing through Sunday and lingering into Monday as a large area of moisture associated with Hone. The heaviest rainfall will likely occur over windward and southeast facing slopes. 2. Tropical storm conditions are possible on the Big Island later Saturday into Sunday. Winds are expected to be strongest where they blow downslope from higher terrain, over headlands, and through passes. 3. Swell generated by Hone is expected to reach the Hawaiian islands Saturday night into Sunday. This swell could cause life-threatening surf and rip currents. Listen for later advisories and possible warnings from the National Weather Service. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 16.1N 144.8W 40 KT 45 MPH 12H 23/1800Z 16.3N 146.7W 40 KT 45 MPH 24H 24/0600Z 16.7N 149.5W 45 KT 50 MPH 36H 24/1800Z 17.1N 152.3W 50 KT 60 MPH 48H 25/0600Z 17.4N 154.7W 55 KT 65 MPH 60H 25/1800Z 17.8N 157.0W 60 KT 70 MPH 72H 26/0600Z 18.4N 158.9W 65 KT 75 MPH 96H 27/0600Z 19.5N 161.5W 65 KT 75 MPH 120H 28/0600Z 20.0N 165.0W 50 KT 60 MPH $$ Forecaster Jelsema