Tropical Cyclone Discussion
031 WTPA44 PHFO 071452 TCDCP4 Hurricane Lowell Discussion Number 46 NWS Central Pacific Hurricane Center Honolulu HI EP122026 Issued by NWS National Hurricane Center Miami FL 500 AM HST Mon Sep 07 2026 Lowell is a well-organized hurricane with a distinct eye and cold cloud tops in the eyewall, though overnight microwave imagery still showed evidence of concentric eyewalls. Intensity estimates are about the same as 6 hours ago, so the initial wind speed is held at 100 kt. Another Air Force Hurricane Hunter aircraft is scheduled to be in the cyclone in a few hours for a better estimate. The initial motion is north-northeastward or 025/12 kt. A cut-off mid- to upper-level low is slowly moving westward to the north- northwest of Hawaii, which should allow the storm to gradually bend more to north during the next 24 hours. However, this northward turn has been delayed from expected, and the guidance has shifted about 30 n mi to the east of the last forecast. NHC's new forecast follows that trend, bringing the hurricane closer to the western Hawaiian Islands. The new forecast necessitates a Tropical Storm Watch for Oahu, and any further eastward adjustments could require a warning later today or this afternoon. Beyond 2 days, Lowell should swing westward as it merges with the upper-low, a few hundred miles north of the northwestern Hawaiian Islands. The forecast is shifted westward at long range, and the system could be close to dissipating as a tropical cyclone on day 5 based on the latest global model forecast. Lowell is starting to encounter increasing shear and cooling waters, which should cause a gradual weakening today, though it is still expected to be a large hurricane as it passes near or just west of Niihau. Rapid weakening is in the forecast after it moves north of the main Hawaiian Islands due to very strong shear and marginal water temperatures. Model guidance is in poor agreement in the medium range due to the upper-level trough interaction, and little change is made to the last forecast at long range. KEY MESSAGES: 1. The core of Lowell is forecast to pass near or just west of Niihau tonight and early Tuesday, and damaging hurricane conditions are expected to begin in Kauai County tonight and continue through Tuesday morning, with tropical storm conditions expected to begin later today. Higher wind gusts are expected atop mountains and on windward and leeward slopes. 2. Periods of heavy rainfall will increase in coverage over the Hawaiian Islands today and continue through Wednesday. This may produce significant flash flooding and mudslides, especially across Kauai county and portions of the Big Island. 3. Large damaging waves are expected to impact exposed portions of Kauai County and are likely to produce coastal flooding and inundation of low-lying areas through early Tuesday. 4. Large swells will produce life-threatening surf and rip current conditions across the remainder of the Hawaiian Islands during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 07/1500Z 17.5N 162.6W 100 KT 115 MPH 12H 08/0000Z 19.5N 161.7W 95 KT 110 MPH 24H 08/1200Z 22.4N 160.9W 85 KT 100 MPH 36H 09/0000Z 25.1N 160.8W 70 KT 80 MPH 48H 09/1200Z 27.0N 161.5W 55 KT 65 MPH 60H 10/0000Z 27.8N 163.5W 50 KT 60 MPH 72H 10/1200Z 27.8N 166.0W 45 KT 50 MPH 96H 11/1200Z 27.5N 170.0W 40 KT 45 MPH 120H 12/1200Z 29.0N 172.0W 35 KT 40 MPH