{"id": "1208369860164780034", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-08T03:00:00Z", "msg": "530\nWTPA44 PHFO 080246\nTCDCP4\n \nHurricane Lowell Discussion Number  48\nNWS Central Pacific Hurricane Center Honolulu HI   EP122026\nIssued by NWS National Hurricane Center Miami FL\n500 PM HST Mon Sep 07 2026\n\nLowell's core structure this afternoon continues to gradually decay\nas it interacts with an upper-level trough and vertical wind shear\nincreases. The eye is no longer observed on satellite imagery, nor\nin radar data from Kauai (PHKI), or from the Air Force Reserve\nHurricane Hunters making center fixes. As Lowell interacts with the\nupper-level trough, the flight-level winds on the eastern side of\nthe storm have increased, with the earlier recon mission finding 700\nmb winds up to 131 kt. However, a dropsonde launched in the area of\nmaximum wind suggested that the flight level wind reduction to the\nsurface was much higher than usual, which makes sense because these\nwinds aloft occurred in an area with few convective echos from the\nPHKI radar. This information provides justification to hold Lowell's\ninitial intensity at 95 kt for this advisory. Another Air Force\nReserve Hurricane Hunter Mission is in the hurricane right now and\nwill continue to provide updated data this evening into the\novernight hours.\n \nThe hurricane's initial motion remains north-northeastward at 025 \ndegrees at 16 kt. Lowell's interaction with a mid- to upper-level \ntrough has led to the storm accelerating to the north-northeast \ntoday as the hurricane is steered between this feature and an \nextensive deep-layer ridge to the east of the Hawaiian Islands. The \nhurricane should maintain this motion with a subtle bend back left \nas it makes its point of closest approach to Kauai tonight. \nUltimately the upper-level trough is forecast to weaken and or lift \nout, with the mid-level ridging building build back to the northwest \nof Lowell. This synoptic pattern should result in the the cyclone \nturning sharply to the northwest and then west in the 36-60 h time \nframe, with the NHC track following the most reliable HFIP Corrected \nConsensus Approach (HCCA) and Google DeepMind (GDMI) aids. At long \nrange, some of the global models continue to hint at another \npossible trough interaction in 96-120 h, and the NHC track forecast \nshows another bend back northwest at that time. However, there \nremains substantial uncertainty in both the deterministic and \nensemble track guidance by the end of the forecast period.\n \nLowell's inner-core structure has been gradually decaying due to \nincreasing vertical wind shear, though the ongoing trough \ninteraction is also enhancing the flight level winds on the \nhurricane's eastern side as it accelerates. While it is possible \nsome baroclinic processes may help to maintain the hurricane's wind \nfield tonight, high shear and decreasing sea-surface temperatures \n(SSTs) should soon result in significant weakening after Lowell \npasses the Hawaiian Islands. Model guidance continues to show Lowell \nweakening below hurricane intensity by tomorrow afternoon, and that \nis reflected in the latest NHC intensity forecast in 24-36 h. \nThereafter, more gradual weakening is expected as the shear \ndecreases and Lowell remains over marginally warm SSTs. Like the \ntrack forecast, the intensity forecast in 96-120 h remains quite \nuncertain, as it is unclear how Lowell's weakened circulation will \ninteract with the next upper-level trough, with solutions ranging \nfrom strengthening to dissipation. The long-range intensity forecast \nremains low confidence, and the official forecast opts to remain \nclose to the guidance mean.\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  08/0300Z 20.3N 161.3W   95 KT 110 MPH\n 12H  08/1200Z 22.7N 160.7W   85 KT 100 MPH\n 24H  09/0000Z 25.3N 160.6W   60 KT  70 MPH\n 36H  09/1200Z 27.2N 161.5W   50 KT  60 MPH\n 48H  10/0000Z 28.2N 163.5W   45 KT  50 MPH\n 60H  10/1200Z 28.2N 166.0W   45 KT  50 MPH\n 72H  11/0000Z 27.9N 168.5W   40 KT  45 MPH\n 96H  12/0000Z 28.0N 171.0W   40 KT  45 MPH\n120H  13/0000Z 30.5N 171.5W   35 KT  40 MPH\n \n"}