{"id": "1213397081734545415", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-25T21:00:00Z", "msg": "241\nWTPA42 PHFO 252056\nTCDCP2\n \nHurricane Nolo Discussion Number  21\nNWS Central Pacific Hurricane Center Honolulu HI   EP152026\nIssued by NWS National Hurricane Center Miami FL\n1100 AM HST Fri Sep 25 2026\n\nThe eye of Nolo is becoming better defined on South Point Hawaii \nradar as well as on the latest satellite imagery, though is still a \nbit ragged.  The Air Force Reserve Hurricane Hunters have found \npeak 700-mb flight-level winds of 106 kt, which generally \ncorrespond to surface winds of about 95 kt using standard reduction \nfactors.  However, the radius-of-maximum winds is pretty large, \nsome dropsonde data suggests it isn't quite mixing down at a normal \nrate, and the central pressure is fairly high around 978 mb.  These \nfactors point to a somewhat lower current wind speed, so the \ninitial intensity is set to 90 kt.  \n\nNolo is gradually bending leftward, with the current motion \nestimated at 015/4 kt.  Nolo should slow down by late tonight and \nstart to drift westward on Saturday as the steering flow changes \nfrom an upper-level trough over the far northwestern Hawaiian \nIslands to a building ridge north of the main Hawaiian Islands.  \nThis ridge is forecast to push Nolo faster to the west by Sunday \nbefore eventually the cyclone is likely to turn more to the \nnorth-northwest early next week due to another encounter with that \nupper trough.  The new model guidance is fairly close to the last \ncycle, and no significant changes were made to the last NHC \nforecast.  \n\nSome increase in shear, along with nearby dry air, could briefly \narrest Nolo's strengthening trend for the next day or so.  After \nthat time, most of the guidance is showing Nolo becoming a very \nstrong hurricane with decreasing shear and increasing ocean heat \ncontent.  The new forecast is leveled off tonight, but then is \nraised from the last one early next week, and I wouldn't be \nsurprised if Nolo ended up stronger in 2-3 days given the upper- \nlevel wind pattern.  Weakening is still expected by days 4 and 5 due \nto forecast strong southwesterly shear east of the trough.\n \nKey Messages:\n \n1. Nolo is expected to 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 tonight 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 late today. 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  25/2100Z 16.5N 155.4W   90 KT 105 MPH\n 12H  26/0600Z 16.9N 155.3W   95 KT 110 MPH\n 24H  26/1800Z 17.1N 155.7W   95 KT 110 MPH\n 36H  27/0600Z 17.0N 157.0W  100 KT 115 MPH\n 48H  27/1800Z 16.8N 158.8W  110 KT 125 MPH\n 60H  28/0600Z 17.2N 160.8W  125 KT 145 MPH\n 72H  28/1800Z 18.4N 162.6W  120 KT 140 MPH\n 96H  29/1800Z 21.5N 164.4W   95 KT 110 MPH\n120H  30/1800Z 23.5N 165.0W   70 KT  80 MPH\n \n"}