{"id": "1208299454857281538", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-07T21:00:00Z", "msg": "346\nWTPA44 PHFO 072048\nTCDCP4\n \nHurricane Lowell Discussion Number  47\nNWS Central Pacific Hurricane Center Honolulu HI   EP122026\nIssued by NWS National Hurricane Center Miami FL\n1100 AM HST Mon Sep 07 2026\n  \nThe satellite presentation of Lowell has slightly degraded during\nthe past several hours, with the Air Force Hurricane Hunter showing\nslowly rising central pressures.  There is also a tilt on recent\nmicrowave imagery due to increasing southwesterly shear, and the\nlow-level center is a bit west of the ragged eye in conventional\nsatellite data.  Although the peak flight-level winds at 700 mb \nwere 113 kt, the plane also reported the loss of an eyewall, which \nsuggests the standard 90 percent rule will be too high for a \nsurface wind reduction.  Thus, the initial wind speed is set to    \n95 kt, which also is close to the most recent JTWC and HFO \nclassifications. \n \nThe initial motion is north-northeastward or 030/15 kt.  Lowell's\nmotion should gradually bend leftward due to the steering from a\nmid- to upper-level low north of Hawaii and a building ridge to the\nnortheast.  The latest guidance is almost the same as before,\nmoving the center just west of Niihau tonight, and the new NHC\ntrack in the short-term is only nudged slightly eastward.  After\npassing the main Hawaiian Islands, Lowell will likely get wrapped\naround the aforementioned upper-level low and take a westward turn\nafter 48 hours.  At long range, the system could turn northwestward\ndue to a new trough interaction, but hopefully it won't survive due\nto its weakened state.  The new forecast is very similar to the\nprevious one, and south of the latest GFS/ECMWF models.\n \nLowell should slowly weaken today due to increasing shear and \ndecreasing SSTs. A more rapid weakening should occur after it \npasses Hawaii overnight as shear gets quite high, and it moves \nover even cooler waters.  Model guidance is showing a much weaker \nsystem by midweek, and the new NHC forecast follows that trend.  \nBeyond Wednesday, only a gradual loss of strength is forecast due \nto shear lessening while the system is over marginally warm waters. \nLowell could be transitioning to a post-tropical cyclone at day 5, \nbut the possible trough interaction is leading to a wide range of \nsolutions from re-strengthening to a quick dissipation.  For now, \nthe forecast will follow the guidance mean, and it should be \nmentioned this is a low-confidence long-range prediction.\n \n \nKEY MESSAGES:\n \n1. Kauai County: The core of Lowell is forecast to pass near Niihau \ntonight and early Tuesday, and damaging hurricane conditions are \nexpected during that time, with the highest winds atop mountains and \non windward and leeward slopes. Large damaging waves will impact \nexposed portions of the coastline, producing dangerous coastal \nflooding and inundation of low-lying areas through early Tuesday. \n\n2. Periods of heavy rainfall will increase in coverage over the \nHawaiian Islands today and continue through Wednesday. This \nmay produce significant flash flooding and mudslides, especially \nacross Kauai County and portions of the Big Island. \n\n3. Oahu: Tropical storm conditions are expected to begin tonight. \nStrong, damaging wind gusts could cause tree damage and power \noutages, especially in areas of higher terrain. \n\n4. Large swells will produce life-threatening surf and rip current \nconditions during the next several days across portions of the \nHawaiian Islands.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  07/2100Z 18.7N 161.8W   95 KT 110 MPH\n 12H  08/0600Z 20.9N 161.1W   85 KT 100 MPH\n 24H  08/1800Z 23.8N 160.8W   65 KT  75 MPH\n 36H  09/0600Z 25.9N 161.1W   55 KT  65 MPH\n 48H  09/1800Z 27.5N 162.4W   50 KT  60 MPH\n 60H  10/0600Z 27.9N 164.8W   45 KT  50 MPH\n 72H  10/1800Z 27.6N 167.4W   40 KT  45 MPH\n 96H  11/1800Z 27.6N 171.0W   40 KT  45 MPH\n120H  12/1800Z 30.0N 172.0W   35 KT  40 MPH\n \n"}