000 WTPA41 PHFO 242039 TCDCP1 Tropical Storm Hone Discussion Number 10 NWS Central Pacific Hurricane Center Honolulu HI CP012024 1100 AM HST Sat Aug 24 2024 Cloud tops around Tropical Storm Hone have warmed noticeably since the overnight convective bloom, but satellite loop shows overall structure remained steady over the past six hours. Movement remains steady as well as the intermediate position at 18Z was exactly along the overnight forecast track. Latest data from U.S. Air Force Reserve Hurricane Hunter aircraft showed maximum sustained winds of 51 knots. This is slightly higher than subjective Dvorak satellite derived intensities of 45 kt from CPHC and JTWC. Direct observations take precedence and the initial intensity for Hone will be maintained at 55 kt. A dropsonde measured a central pressure of 1000 mb, a slight increase from last night. The initial motion is set at 280/13, unchanged from the last full forecast cycle. Slightly north of due west, this motion is expected to continue over the next several days due to the influence of a subtropical ridge to the north. Some slowing in forward motion is anticipated as the ridge weakens slightly. Hone is expected to pass near or just south of the Big Island of Hawaii later today through early Sunday, where a Tropical Storm Warning remains in effect. By the middle of the coming week, Hone will likely become increasingly shallow as vertical wind shear increases, allowing low-level trade wind flow to steer the system toward the west-southwest. The official forecast track is nearly identical to the previous advisory and closely follows the tightly clustered consensus guidance. Environmental conditions affecting Hone will remain steady over the next 24 hours, with sea surface temperatures between 26C and 27C, light to moderate vertical wind shear, and marginally sufficient mid-level moisture. Slow strengthening is expected to continue through tonight. Sea surface temperatures are forecast to rise to around 27C beyond 24 hr. However, guidance presents a rather compelling case for capping Hone's intensity at 60 kt Sunday and Monday, just below hurricane strength. As Hone continues westward, increasing vertical wind shear may weaken it later Monday through the middle of next week. The intensity forecast closely follows dynamical consensus guidance. KEY MESSAGES: 1. There is the potential for excessive rainfall and flash flooding on portions of the Big Island of Hawaii starting this afternoon and continuing through Sunday as a large area of moisture associated with Hone moves through. The heaviest rainfall will likely occur over windward and southeast facing slopes. 2. Tropical Storm conditions are expected on the Big Island, beginning as early as this evening and continuing through early Sunday. Winds are expected to be strongest downslope of higher terrain, over headlands, and through passes. 3. Swells generated by Hone will impact the Hawaiian islands through Sunday, creating life-threatening surf and rip currents. Please consult surf products from the National Weather Service in Honolulu. FORECAST POSITIONS AND MAX WINDS INIT 24/2100Z 17.7N 153.2W 55 KT 65 MPH 12H 25/0600Z 18.1N 155.1W 55 KT 65 MPH 24H 25/1800Z 18.5N 157.3W 60 KT 70 MPH 36H 26/0600Z 18.8N 159.6W 60 KT 70 MPH 48H 26/1800Z 19.0N 161.8W 60 KT 70 MPH 60H 27/0600Z 19.3N 163.8W 55 KT 65 MPH 72H 27/1800Z 19.5N 165.6W 50 KT 60 MPH 96H 28/1800Z 20.2N 168.8W 40 KT 45 MPH 120H 29/1800Z 21.3N 172.0W 30 KT 35 MPH $$ Forecaster Powell