{"id": "1213254401388249095", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-25T09:00:00Z", "msg": "843\nWTPA42 PHFO 250850\nTCDCP2\n \nHurricane Nolo Discussion Number  19\nNWS Central Pacific Hurricane Center Honolulu HI   EP152026\nIssued by NWS National Hurricane Center Miami FL\n1100 PM HST Thu Sep 24 2026\n \nAn Air Force Reserve reconnaissance mission has provided some \nconflicting data regarding Nolo's current intensity. On one hand, \nthe plane measured a peak flight-level wind of 81 kt in the \nsoutheastern eyewall, which reduces to an intensity of 70-75 kt. On \nthe other hand, the central pressure has not fallen since the \nprevious mission, with the latest dropsonde data suggesting around \n985 mb, and the 700-mb height has risen a bit. For now, the initial \nintensity is raised conservatively to 70 kt. Deep convection is \nbecoming more symmetric around the eye, which is a bit ragged and \nelliptical.\n\nThe initial motion remains north-northeastward, or 030/4 kt, with \nNolo being steered by a deep-layer trough located west of the \nHawaiian Islands. This trough is expected to weaken and drift \nwestward during the next 24-36 hours, with strong mid-level ridging \ntaking its place over and north of Hawaii. As a result, Nolo is \nexpected to come to a crawl by Friday night and early Saturday and \nthen begin to move south of due west through Sunday. The track \nguidance has again shifted southward, responding to the \nstrengthening ridge, and the NHC forecast lies near the northern \nedge of the envelope, closest to the Google DeepMind ensemble mean \n(GDMI). With nearly every other major model lying south of the \nofficial forecast, additional southward shifts in future \nadvisories are possible, but not yet a guarantee.  The previously \nmentioned deep-layer trough is expected to re-amplify later in the \nforecast period, which is expected to cause Nolo to turn \nnorthwestward and then north-northwestward by Monday and Tuesday.\n\nVarious shear analyses suggest that Nolo is experiencing moderate \ndeep-layer shear out of the south-southeast, which may be \ncontributing to the broken eyewall on the east side. However, the \nshear is expected to abate during the next 24-36 hours, and along \nwith warm sea surface temperatures, should support continued \nstrengthening. There is a bit of model disagreement on exactly how \nmuch strengthening will occur, but it is noteworthy that the \ntypically skillful HCCA model, as well as HAFS-A, shows Nolo \nreaching high-end category 4 strength in 3-4 days. As a result, the \nNHC intensity forecast has been increased slightly at that forecast \ntime. Weakening is anticipated by days 4 and 5 due to a marked \nincrease in southwesterly shear east of the trough.\n\n \nKey Messages:\n \n1. Nolo is expected remain south of the Big Island of Hawaii \nthrough Saturday before turning westward and moving away from the \nisland.  Tropical storm conditions are expected to begin on the Big \nIsland Friday night with hurricane conditions possible on Saturday, \nparticularly in areas of steep terrain.  Residents should follow \nadvice given by local officials, including evacuating if told to do \nso.\n \n2. The time to finish preparations for significant heavy rain and \nflooding impacts on the Big Island is now as heavy rain increases in \nboth coverage and intensity on Friday. Periods of heavy rain are \nexpected to continue across the Big Island and Maui through the \nweekend. Life-threatening, catastrophic flooding and mudslides are \npossible, especially in areas of steep terrain across the eastern \nand southern portions of the Big Island and Maui. Across the \nremainder of Hawaii, lesser rainfall totals are expected, with \nisolated flooding possible.  \n \n3. Large and damaging waves are likely along portions of the\nBig Island's coastline into the weekend.\n \n4. A Tropical Storm Watch is in effect for Maui County where\ntropical storm conditions are possible beginning on Saturday.\nInterests elsewhere in Hawaii should closely monitor the latest\nforecast updates and ensure that they have their preparedness plans\nin place.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  25/0900Z 15.5N 155.6W   70 KT  80 MPH\n 12H  25/1800Z 16.0N 155.4W   85 KT 100 MPH\n 24H  26/0600Z 16.6N 155.2W   90 KT 105 MPH\n 36H  26/1800Z 16.7N 155.6W   95 KT 110 MPH\n 48H  27/0600Z 16.5N 156.7W  100 KT 115 MPH\n 60H  27/1800Z 16.2N 158.5W  110 KT 125 MPH\n 72H  28/0600Z 16.4N 160.5W  120 KT 140 MPH\n 96H  29/0600Z 18.5N 163.5W  110 KT 125 MPH\n120H  30/0600Z 21.3N 164.5W   85 KT 100 MPH\n \n"}