000 WTPA41 PHFO 240902 TCDCP1 Tropical Storm Hone Discussion Number 8 NWS Central Pacific Hurricane Center Honolulu HI CP012024 1100 PM HST Fri Aug 23 2024 The appearance of Tropical Storm Hone has improved significantly from earlier this afternoon, with deep convection over the low-level circulation center and convective banding nearly encircling the storm. The latest Subjective Dvorak intensity estimates came in at 2.5 from all fix agencies with UW-CIMSS ADT and AiDT coming in at 32 and 36 knots respectively. Valuable information was received from a U.S. Air Force Reserve Hurricane Hunter aircraft which sampled Hone once again this evening. The aircraft sampled maximum sustained flight level winds of 56 knots, which reduces to 50 knots at the surface, max SFMR winds of 43 knots, and maximum MBL winds of 54 knots, which reduces to 45 knots at the surface. Taking a blend of these data and accounting for the improvement in structure of the system, the initial intensity will be increased to 50 knots with this advisory package. The central pressure of Hone was lowered to 998 mb due to dropsonde data obtained by the aircraft. The initial motion has shifted a bit further north of due west, and is set at 285/12 for this advisory. This general motion, slightly north of due west, will continue during the next several days as Hone is steered by a deep subtropical ridge to the north. However, some slowing of the forward motion is expected as the deep ridge to the north of Hone weakens slightly. Along this track, Hone will be passing near or just south of the Big Island of Hawaii late Saturday into early Sunday, and a Tropical Storm Warning remains in effect for the Big Island of Hawaii. By the middle of next week, Hone will likely become increasingly shallow as vertical wind shear increases, allowing the low level trade wind flow to steer the system toward the west. The official forecast track has been nudged a bit north of the previous advisory due to the recent movement trends of the system, and closely follows the tightly clustered consensus guidance. Environmental conditions will change little during the next 24 hours, with sea surface temperatures between 26C and 27C, light to moderate vertical wind shear, and marginally sufficient mid-level moisture. As a result, the forecast calls for continued slow strengthening. Beyond 24 hours, sea surface temperatures increase to around 27C and ocean heat content becomes more favorable as well. This should allow Hone to reach Hurricane strength Sunday through Monday, before increasing vertical wind shear weakens the system Monday night through the middle of next week. The intensity forecast follows dynamical consensus guidance closely and is similar to the previous advisory package. KEY MESSAGES: 1. There is the potential for excessive rainfall and flash flooding on portions of the Big Island of Hawaii starting Saturday afternoon and continuing through Sunday as a large area of moisture associated with Hone moves over parts of the Hawaiian Islands. The heaviest rainfall will likely occur over windward and southeast facing slopes. 2. Tropical storm conditions are possible on the Big Island Saturday afternoon 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 later tonight, then spread to the remainder of the state through the rest of the weekend. These swells will produce life-threatening surf and rip currents. Listen for later advisories and possible warnings from the National Weather Service. FORECAST POSITIONS AND MAX WINDS INIT 24/0900Z 17.4N 150.5W 50 KT 60 MPH 12H 24/1800Z 17.7N 152.6W 55 KT 65 MPH 24H 25/0600Z 17.9N 154.9W 60 KT 70 MPH 36H 25/1800Z 18.3N 157.1W 65 KT 75 MPH 48H 26/0600Z 18.7N 159.2W 65 KT 75 MPH 60H 26/1800Z 19.0N 161.1W 65 KT 75 MPH 72H 27/0600Z 19.4N 162.9W 60 KT 70 MPH 96H 28/0600Z 20.0N 166.5W 45 KT 50 MPH 120H 29/0600Z 20.6N 170.5W 35 KT 40 MPH $$ Forecaster Jelsema