Tropical Cyclone Discussion
196 WTPA42 PHFO 151453 TCDCP2 Tropical Storm Lala Discussion Number 13 NWS Central Pacific Hurricane Center Honolulu HI CP012026 Issued by NWS National Hurricane Center Miami FL 500 AM HST Sat Aug 15 2026 A ragged eye-like feature has formed in radar imagery from the South Point, Hawaii, radar site, even though Lala's satellite presentation has not improved much since the previous advisory. Radar velocities are as high as 55-60 kt between 10,000 and 15,000 ft in deep convection to the northeast of the center. Along with satellite estimates, these data support holding Lala's intensity at 55 kt. Lala's current motion remains west-northwestward, or 285/11 kt, but that is likely to change later today as the circulation begins to interact with terrain of the Big Island. Dynamical model fields suggest that the center may get pulled northwestward into or near the Big Island later this afternoon while at the same time a leeside trough or broad low forms west of the island. This may cause a discontinuous track that is reflected in the official forecast points or track forecast cone. After the cyclone reconstitutes itself west of the Big Island, it is likely to turn toward the west on Sunday and continue on that path for several days due to high pressure north of the Hawaiian Islands. A shortwave trough moving across the northern Pacific around the middle of next week may weaken the ridge enough to allow Lala to turn toward the west-northwest and then northwest, potentially approaching western portions of the Northwestern Hawaiian Islands. Lala has about 12 hours left for some strengthening before the center reaches the Big Island, and the NHC forecast continues to show the storm becoming a hurricane near the southern coast of the Big Island. Even if the storm only manages to strengthen slightly, there is no practical difference between a 60-kt tropical storm and a 65-kt hurricane, especially since hurricane-force gusts are expected on the Big Island regardless. Weakening is expected after the circulation interacts with the Big Island, and it will likely take a few days for the storm to re-organize. Environmental conditions appear conducive to support intensification in 3-5 days. The intensity guidance has not changed much of this cycle, and the new NHC forecast is very similar to the previous one. Lala's center is sufficiently well defined in radar imagery that we plan to start hourly updates at 6 AM HST (1600 UTC) via the Tropical Cyclone Update product (HFOTCUCP2). These hourly updates will continue as long as the center remains well defined in radar imagery. Key Messages: 1. Damaging hurricane-force winds are expected on the Big Island of Hawaii later today, with the strongest wind gusts expected in areas of higher terrain. Tropical-storm-force winds are already beginning on the Big Island, and preparations should now be complete. Tropical-storm-force wind gusts are also beginning across portions of the smaller islands and should continue through Sunday. 2. Heavy rainfall will continue to increase over the Big Island this morning and then spread westward across the remainder of the island chain over the weekend. This rainfall will produce life-threatening flooding and mudslides, especially in areas of steep terrain. 3. Large and dangerous waves are expected across portions of the Hawaiian Islands this weekend. Surf is already building along east-facing shores and will increase along exposed southern shores as Lala passes through the region. This heavy surf may cause localized coastal flooding and significant beach erosion. FORECAST POSITIONS AND MAX WINDS INIT 15/1500Z 17.8N 154.6W 55 KT 65 MPH 12H 16/0000Z 18.7N 155.5W 65 KT 75 MPH 24H 16/1200Z 19.9N 158.1W 55 KT 65 MPH 36H 17/0000Z 20.3N 160.9W 50 KT 60 MPH 48H 17/1200Z 20.5N 163.2W 50 KT 60 MPH 60H 18/0000Z 20.6N 165.4W 55 KT 65 MPH 72H 18/1200Z 20.7N 167.3W 60 KT 70 MPH 96H 19/1200Z 21.6N 170.5W 65 KT 75 MPH 120H 20/1200Z 23.5N 172.7W 70 KT 80 MPH