Tropical Cyclone Discussion
709 WTPA44 PHFO 061449 TCDCP4 Hurricane Lowell Discussion Number 42 NWS Central Pacific Hurricane Center Honolulu HI EP122026 Issued by NWS National Hurricane Center Miami FL 500 AM HST Sun Sep 06 2026 An Air Force Reserve Hurricane Hunter aircraft completed a mission in Lowell a few hours ago and measured peak 700-mb flight-level winds of 114 kt, which typically equates to an intensity of 100-105 kt. However, dropsonde data from the plane also indicated that the central pressure (943 mb) was a bit lower than previously estimated. For that reason, Lowell's currently intensity is held at 110 kt, which is also very close to the latest UW-CIMSS DPRINT and SATCON estimates. Lowell is in the midst of its anticipated sharp turn, and the current motion is north-northwestward (335/5 kt). The steering continues to be dominated by a cutoff mid-/upper-level low located about 350 n mi north-northeast of Hawaii, which is forecast to move west-southwestward and cause Lowell to accelerate toward the north and north-northeast through Monday night. The track guidance is tightly packed through that period, although some of the better-performing models (HCCA and GDMI) lie along the eastern edge of the envelope. That required an additional eastward nudge in the official forecast, bringing Lowell's center near or over the island of Nihoa in 48 hours and about 100 n mi west of Kauai County. After the center passes the Hawaiian Islands, model guidance is in good agreement that Lowell will turn westward by early Friday, but there is some disagreement on the sharpness of that turn. Vertical shear is expected to remain low for another 12 hours, so fluctuations in intensity will still be possible through this afternoon. South-southwesterly shear is forecast to increase to strong levels by tonight, which should induce a gradual weakening trend while Lowell is passing the Hawaiian Islands. However, even with the weakening, Lowell is not expected to change much in size, and tropical storm conditions are forecast to spread across Kauai and Niihau by Monday afternoon, necessitating the issuance of a tropical storm warning. Lowell is forecast to weaken to a tropical storm by early Wednesday after passing the Hawaiian Islands, and continued weakening is expected through the end of the week due to continued shear, marginal sea surface temperatures, and dry mid-level air. KEY MESSAGES: 1. Lowell is forecast to pass west of Kauai County late Monday into early Tuesday. A Tropical Storm Warning is now in effect for Kauai County, including Kauai and Niihau, where tropical storm conditions are expected to begin Monday afternoon and continue through Tuesday morning. Strong wind gusts will be possible atop mountains and on windward and leeward slopes. 2. Heavy rainfall associated with Lowell will begin to impact the Hawaiian Islands today and continue through early this week. Periods of heavy rain may produce significant flash flooding and mudslides, especially across Kauai County and portions of the Big Island. 3. Large swells from Lowell are expected to produce life-threatening surf and rip current conditions across portions of the Hawaiian Islands during the next several days. Surf along exposed portions of Kauai County could also produce coastal flooding and inundation of low-lying areas Monday through Monday night. FORECAST POSITIONS AND MAX WINDS INIT 06/1500Z 14.7N 163.8W 110 KT 125 MPH 12H 07/0000Z 15.6N 163.9W 110 KT 125 MPH 24H 07/1200Z 17.5N 163.3W 105 KT 120 MPH 36H 08/0000Z 20.0N 162.5W 100 KT 115 MPH 48H 08/1200Z 23.0N 161.9W 90 KT 105 MPH 60H 09/0000Z 25.4N 162.0W 75 KT 85 MPH 72H 09/1200Z 26.9N 162.8W 65 KT 75 MPH 96H 10/1200Z 27.9N 166.6W 50 KT 60 MPH 120H 11/1200Z 27.7N 170.6W 40 KT 45 MPH