In brief: Neither Atlantic system appears to have much of a future ahead of itself. However, Tropical Storm Lala will hit Hawaii, probably as a hurricane this weekend. We detail the impacts and put some historical context around it below.
Atlantic update
Development odds on Invest 92L have been nudged back this morning, while Invest 94L is basically unchanged. Neither system looks especially great and neither has particularly good long-term prospects.
For Invest 92L, it will continue into the islands tonight and tomorrow, then across the southern Caribbean as a remnant. No further development is expected once in the Caribbean.
For 94L, the prognosis might be a little less grim. It’s playing the Tortoise and the Hare game, where slow and steady wins the race. In this case, “winning the race” is basically just acquiring status as a depression or tropical storm. It will move slowly west and west-northwest across the Atlantic, arriving at the doorstep of the islands by about early to midweek next week. The slow movement likely exposes it to strong wind shear at times. This will likely keep a lid on development prospects to some extent, which is why this carries about a 50/50 chance versus an 80/20 chance or something.
Neither Google Deep Mind, nor the AIFS really do much with this system. Even the occasionally robust European ensemble has little. Basically, 94L seems destined to be not much of anything.
Behind 94L, we don’t have any real specific systems of note, so the Atlantic continues onward quietly.
Tropical Storm Lala and Hawaii
Lala was named yesterday, shortly after our morning post. It’s a strong tropical storm now, with max sustained winds of 60 mph. Expect Lala to become a hurricane later today.
Lala is in an environment of low shear now, only around 6 kts or so out of the west, per tcatlas.org. If there’s one health issue with Lala, it’s that it’s got a bit of dry air stuck in the mid-levels of the storm. So while it’s doing well, it has some underlying issues that could impede it at some point. But for now, we’re on the way to hurricane intensity with Lala by later today in all likelihood.
As Lala comes west, it will begin to “feel” the impact of the Big Island of Hawaii. Mauna Kea is almost 14,000 feet tall, so that obviously has some impact on approaching storms. In this case, it will likely slow Lala down and may lead to erratic motion. As this happens, a boatload of rain will fall on the east/southeast facing side of the Big Island.
Upwards of 25 inches of rain could fall on the eastern part of the Big Island, on the east slope of Mauna Loa, south of Hilo in Puna, and just inland from Kilauea. Of course, having two monster peaks in Mauna Kea and Mauna Loa means the west side of Hawaii gets rain shadowed. So the Kona region may only see 1 to 4 inches of rain. Look for high totals on the east shore of Maui from Hana into the Upcountry, heading up to Haleakalā. Lower totals are likely for the other islands.
Obviously, concerns about flooding and mudslides will be high in southeastern parts of Hawaii and flood watches are posted for the Big Island and Maui.
Beach erosion and coastal flooding are possible in the islands, especially on the Big Island. And obviously, rough surf advisories are posted with the increasing swells likely ahead of Lala.
With breezy and dry conditions ahead of Lala’s circulation, there could be some elevated wildfire risk today (Friday) in the islands.
Lala is expected to be a category 1 hurricane as it passes the Big Island, so wind gusts will be strong, especially given the terrain impacts of the Big Island and Maui. Winds will be less of a concern farther to the north and west in the island chain.
Intensity-wise, Google’s Deep Mind shows Lala becoming a borderline category 2 storm as it passes the Big Island. Notice how it weakens after 48 hours. Land interaction may significantly disrupt Lala and it will need some time on the other side of the islands to get itself back together. Either way, this is likely to be a significant storm in terms of impact for Hawaii. This may be the most significant storm since 2014’s Tropical Storm Iselle on the Big Island.
Iselle was a hurricane ultimately, but a tropical storm as it passed through the Big Island. With Lala expected to be a hurricane and coming dangerously close to a direct hit, this could be a historic storm for the Big Island. A Hawaiian island last took a direct hit from a hurricane in 1992, when much stronger Hurricane Iniki hit Kauaʻi.
Folks in Hawaii should be prepared for Lala.