(BIVN) – As of 6 a.m., Tropical Storm Lala was located 100 miles southeast of South Point on Hawaiʻi island, heading west northwest at 13 mph.
Lala has yet to grow stronger, still maintaining sustained winds of 65 mph. Some strengthening is still possible Saturday, and Lala could be near or at hurricane intensity while it is near the south-side of Hawaiʻi island.
“Some erratic motion is likely later today and tonight while Lala interacts with the Big Island of Hawaii,” the Central Pacific Hurricane Center stated.
A Hurricane Warning remains in place for Hawaiʻi island. In an updated statement issued at 6 a.m., forecasters reported tropical-storm-force wind gusts “are occurring at elevated locations on the Big Island and Maui.”
On Hawaiʻi island, a wind gust of 45 mph (72 km/h) was reported at Puʻuloa, and a wind gust of 44 mph (71 km/h) at Waimea.
A Flood Advisory has been issued for parts of Hilo, Puna, and Hāmākua. Lala is expected to produce rainfall totals of 10 to 20 inches across the Big Island, with maximum totals of 25 inches possible, forecasters warned.
A High Surf Warning is in effect for east-facing shores. “For the Big Island, dangerously large surf increasing from 15 to 20 feet this morning to 18 to 22 feet for the windward coast and as high as 25 to 30 feet for the southeast coast this afternoon,” the National Weather Service said.
From a Central Pacific Hurricane Center discussion posted at 5 a.m. on Saturday morning:
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.
