ZCZC HFOTCDCP1 ALL TTAA00 PHFO DDHHMM Hurricane Hone Discussion Number 12 NWS Central Pacific Hurricane Center Honolulu HI CP012024 1100 PM HST Sat Aug 24 2024 Hone is passing by around 50 nautical miles south of South Point on the Big Island of Hawaii this evening, where it is within radar range. Combined radar and data from the Air Force Reserve reconnaissance aircraft support raising the intensity to 65 knots, making Hone a Category 1 Hurricane. Despite recent subjective Dvorak estimates suggesting a slightly lower intensity, the satellite presentation has evolved markedly from this afternoon, with cold cloud tops near -80 C reinforcing the aircraft-based intensity. Additionally, a dropsonde report measured a central pressure of 991 mb, depicting a significant decrease from this afternoon. The initial intensity is raised to 65 kt for this advisory. The initial motion of Hone is set at 280/10, consistent with the previous forecast cycle. This slightly north of due west trajectory is expected to persist over the coming days, influenced by the subtropical ridge to the north. However, as Hone passes near the Big Island overnight into Sunday, the mountainous terrain could influence local steering currents, potentially leading to localized and short-term deviations in the storm's motion and intensity. A gradual slowing in forward speed is anticipated Sunday into Monday as the ridge weakens slightly. As we move into the early to mid portion of the week, Hone is projected to encounter increasing vertical wind shear, which is expected to weaken the storm and make it more shallow. This change in conditions will allow the low-level trade wind flow to steer the system toward the west-southwest. The official forecast track remains nearly identical to the previous advisory and is closely aligned with the tightly clustered consensus guidance. Environmental conditions affecting Hone will remain steady over the next 24 h, with sea surface temperatures between 26 C and 27 C, light to moderate vertical wind shear, and sufficient mid-level moisture. This supports maintaining a steady trend through Sunday. Although sea surface temperatures are forecast to rise to around 27 C Sunday night and beyond as Hone continues westward, increasing vertical wind shear will gradually weaken the storm Sunday night through the middle of next week. The intensity forecast closely follows dynamical consensus guidance. KEY MESSAGES: 1. Tropical Storm conditions are expected on the Big Island beginning through early Sunday. Winds are expected to be strongest downslope of higher terrain, over headlands, and through passes. 2. Hone is expected to produce storm total rainfall of 6 to 12 inches over mainly windward and southeast facing slopes of the Big Island, with locally higher amounts possible. Rainfall totals of 2 to 4 inches will be possible over portions of the smaller islands, mainly windward. 3. Swells generated by Hone will continue through Sunday as this system continues westward. Expect dangerous conditions with life-threatening surf and rip currents. FORECAST POSITIONS AND MAX WINDS INIT 25/0900Z 18.2N 155.3W 65 KT 75 MPH 12H 25/1800Z 18.6N 157.0W 65 KT 75 MPH 24H 26/0600Z 19.0N 159.2W 60 KT 70 MPH 36H 26/1800Z 19.2N 161.4W 55 KT 65 MPH 48H 27/0600Z 19.3N 163.6W 50 KT 60 MPH 60H 27/1800Z 19.6N 166.0W 50 KT 60 MPH 72H 28/0600Z 19.9N 167.9W 45 KT 50 MPH 96H 29/0600Z 20.7N 171.1W 35 KT 40 MPH 120H 30/0600Z 21.2N 174.4W 30 KT 35 MPH $$ Forecaster Jelsema/Gibbs NNNN