In brief: Invest 94L’s future is obliteration, as the Atlantic settles back down. Tropical Storm Lala will bear down on Hawaii today and tomorrow with strong winds and heavy rainfall.
Atlantic update
The risk of any tropical development in the Atlantic has all but vanished at this point, with the odds of Invest 94L developing down to 10 percent today.
Satellite view of Invest 94L on Saturday morning. (WeatherFront)
This is very reminiscent of 2025, when the models would get a little excited about a wave in the Atlantic, only to have it stumble and faceplant in the end. Invest 94L looks to be obliterated by wind shear and dry air issues.
The next one to watch will be the next wave to emerge off Africa. At this point, I see no reason why this won’t meet a similar fate to 92L and 94L. We’ll keep watching.
Tropical Storm Lala
Meanwhile near Hawaii, Lala is beginning to bear down on the Big Island. Some of the higher elevation locations are gusting over 50 mph now.
Tropical Storm Lala approaching the Big Island on Saturday morning. (WeatherFront)
There is still some chance that Lala could attain hurricane intensity on approach to the Big Island, but it’s not going to change the forecast impacts much. Strong winds, heavy rain, and rough seas remain the story.
As Lala passes the Big Island, the interaction with the mountains is likely to lead to some erratic movement and weakening. It will re-emerge on the other side, jostle north a bit, and then go back on its west-northwest track.
Rain forecast from Tropical Storm Lala as it passes Hawaii. (NOAA WPC)
The total forecast rainfall from Lala has not changed a significant amount since yesterday, with upwards of 25 inches possible on the windward side of the Big Island. Yesterday, when I was discussing major impacts to the Big Island, I neglected to include 2018’s Hurricane Lane. Although it passed well south and west of the islands, it slowed, weakened, and allowed for punishing rains of almost Harvey levels to impact the Big Island. Lane’s problem was that it slowed and nearly stalled. In this case, Lala should continue moving. So generally speaking, while there will be serious rainfall with Lala, we probably aren’t looking at something like that.
Winds will likely cause some damage, especially in Maui and on the Big Island. The strongest winds will be in the high terrain and downwind from the higher mountains, with tropical storm force winds a possibility across the entire island chain. For places like Oahu, the intensity of the wind may depend a bit on how far north Lala comes before turning back west-northwest.
The forecast track of various Google AI models and the European ensemble around Hawaii. (Google Deep Mind)
There’s a lot of spread still, with some model ensemble members coming only within about 60 to 80 miles of the other islands. So folks outside the hardest impacted areas will need to take this seriously.
After tomorrow, Lala will be on its way west and the cleanup can begin.
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.
(WeatherFront)
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.
Of the 51 members of the AIFS, as an example above, only about 5 to 10 percent keep 94L coherent past the islands, most on the very low end of intensity too. (Tomer Burg)
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.
TS Lala this morning. (WeatherFront)
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.
Forecast rain totals for Lala (NHC NOAA)
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.
Google Deep Mind intensity forecast for Lala over the next 72 hours. (tcatlas.org)
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.
Known hurricane history around Hawaii since the 1800s. (tcatlas.org)
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.
In brief: The Atlantic tropics remain noisy but not exactly substantive. Invests 92L and 94L are both expected to attempt to develop but likely struggle. Meanwhile, Hawaii should prepare for a tropical storm impact this weekend.
Atlantic side of business
In yesterday’s post we noted that, “there’s another system in the far north Atlantic that is not a threat to land, but we could see a throwaway depression or “C” storm before it dissipates.” Indeed, if you blinked, you may have missed that Tropical Storm Cristobal formed yesterday, and is on the way to dissipating today.
(WeatherFront)
It appears as a “naked swirl,” or something more out of Cinnabon’s test kitchen. I’m just saying. Cristobal has thus far matched Arthur in ACE, which is to say less than 1, which is to say, basically a rounding error in a typical season. But weak storms count too, so there you have it.
Invest 92L
Meanwhile, south of Cristobal in the Atlantic Main Development Region (MDR) remains Invest 92L, a somewhat healthier looking tropical disturbance today.
Invest 92L keeping the thunderstorms going today. (WeatherFront)
92L isn’t exactly well organized but it’s better than it looked 24 hours ago. Models remain sort of split on whether or not this gets to a point if it actually develops, but given the look this morning, my hunch is that it will find a way. Still, wind shear is currently an issue, especially just north of the disturbance. And models are in decent agreement that it’s unlikely to pass much farther along than tropical depression status, keeping it generally poorly organized. This should allow for a due west track into the Caribbean, where doom awaits 92L’s future.
Invest 92L may become a depression before moving into the Windward or southern Leeward Islands this weekend. (Weathernerds.org)
For the islands, this looks like a bit of a rainmaker but not much beyond that. Once in the Caribbean, it will be greeted by another shot of 20 to 30 knots of wind shear to the face, which should shred it apart. At this point, we don’t really expect any remnant to track as it continues west, so for the Gulf and western Caribbean, this is probably nothing to be worried about. We’ll obviously let you know if that changes.
Invest 94L
To the east of 92L is our latest Invest, 94L. While 94L looks less impressive than 92L this morning, it is carrying some thunderstorms, and it may be more apt to develop, as 92L has helped “seed” the lane in front of 94L with added moisture. It, too will have ample wind shear to fend off, however. The Atlantic is not for the weary of tropical systems right now. If 94L can survive that with some structure in tact, it may have a better long-term prognosis than its partner to the west.
Invest 94L will have to manage shear, but it may have a slightly better long term prognosis than 92L. (WeatherFront)
Assuming it survives, it may begin to develop a bit more east of the islands. Otherwise, it is likely to meet a somewhat similar fate to Invest 92L. If it does develop, it will likely hook northwest and north into the open Atlantic. Currently, about 20 percent of reasonably decent ensemble members do this. And within the tropical models, the majority keep 94L below tropical storm intensity.
Forecast models are not bullish on Invest 94L’s future intensity. (Tropical Tidbits)
Conditions appear hostile overall, but it’s possible we sneak a depression out of this perhaps.
Right now, we just aren’t seeing the setup required to generate meaningful, higher end tropical activity. This is what was expected this summer, and it appears that’s what we’re getting.
Pacific potential
A good news/bad news type situation setting up for Hawaii. The good news is that it does not appear that Invest 93C, which has been reclassified as Potential Tropical Cyclone One-C is going to be a big time hurricane as it passes Hawaii. The bad news is that we do expect tropical storm impacts in Hawaii by this weekend.
PTC-1C’s forecast from the NHC. (NOAA)
The system is struggling to organize initially because of its sprawling nature. Over the next day or so, we should see it begin to consolidate around a formal center and slowly organize. Modeling is in decent agreement in a track near or just south of the Big Island, as well as slow, steady intensification. This should allow for a moderate tropical storm to track near Hawaii on Saturday. We should see tropical storm watches issued later today.
Rain totals from the European operational model show as much as 10 inches of rain or even more on parts of the Big Island and high amounts on Maui as well. (WeatherFront)
The European model has a track fairly close to the NHC’s track right now, just south of the Big Island. This allows for 10 inches or more of rain on the east and southeast facing slopes, with downwind rain shadowing lowering amounts to an inch or so on the northwest edge of the island. A similar story on Maui. These amounts may change in the coming days as the storm track and organization is finalized. This will increase the risk of flooding and mudslides on the Big Island this weekend.
Obviously, winds will be a concern too and will be honed in on as we get a bit closer. Some wind speeds could be enough to cause some damage in localized parts of the islands pending terrain effects. And fire weather may tick up as a concern tomorrow ahead of the storm. Interests in Hawaii should find local sources and follow them and heed the advice of local officials ahead of this storm.
In brief: Invest 92L in the Atlantic is struggling to organize and it likely is en route to eventually dying off in the Caribbean. Behind 92L, another system has some development chances as well heading toward next week. And in Hawaii, folks should continue monitoring Invest 93C, which should become a depression or storm today or tomorrow, approaching Hawaii this weekend as a tropical storm or perhaps lower-end hurricane.
A sorta busyish Atlantic
We are now up to about an 80 percent chance of development in the Atlantic today from the tropical wave we’ve been watching. It’s been tagged as Invest 92L as well, so we get more things to watch on it as it moves. Satellite tells you that this system is not exactly crushing it this morning.
Satellite view of Invest 92L Wednesday AM. (WeatherFront)
Despite the lack of meaningful storms, there is a definitive “twist” to the disturbance right now, so it’s getting somewhere.
(Tropical Tidbits)
I would expect we see a depression out of this within a day or so.
The environment surrounding Invest 92L is not exactly ideal. While the system itself is somewhat cocooned in a small area, it has to deal with significant wind shear just north and on the southeast flank, as well as oodles of Saharan dust immediately north. Basically, there is going to be a functional limit on this system’s intensity because even if it does grow, it will immediately “feel” the shear and dry air more aggressively.
(University of Wisconsin CIMSS)
So what does that mean going forward? Well, Invest 92L, whatever it is, should be approaching the Lesser Antilles in about 3 to 4 days. As it gets there, it will have a couple choices. Either go north out to sea through a weakness in high pressure in the Atlantic, or continue west into the gauntlet that is the highly sheared Caribbean.
Upper air pattern look from European model on Saturday showing Invest 92L approaching the islands. (WeatherFront)
When dealing with tropics, we usually have a rule that goes “weaker west.” In other words, if 92L struggles, it will likely just keeping plodding west into the Caribbean. At that point, it would almost certainly succumb to wind shear, and that’d be that. If 92L can get a modest organization together, it would be more apt to “feel” the weakness in between the areas of high pressure in the Atlantic, the escape hatch if you will. In that case, it would likely turn north and probably end up heading out to sea. I think the smart money is to the west into the Caribbean.
Note, behind 92L is another tropical wave. You can see it on that Euro model depiction above. This one is currently flagged with 30% development odds. At this point, modeling seems to be very mixed on the future of this system. The AIFS and Euro are a little more excited, whereas Google’s modeling (both operational and the 1,000 member ensemble) are lukewarm.
AIFS ensemble. (Weathernerds.org)
The AIFS ensemble is above, and if you live on the East Coast, you’re probably looking at that and saying, “Um.” But the reality is a.) I’m not sure we even get to this point yet. And b.) This assumes the next wave even develops at all. The overall pattern is supportive of keeping any storm tracking north into the Atlantic out at sea, so if I live on the coast, I wouldn’t be sweating either of these waves right now. We’ll keep you posted.
There’s another system in the far north Atlantic that is not a threat to land, but we could see a throwaway depression or “C” storm before it dissipates.
Hawaii risks?
Shifting into the Pacific, we continue to track Invest 93C. Odds of development of this system remain high, but admittedly, it has been sluggish to really get going. This is decent news for Hawaii.
Invest 93C (to the east is Invest 99E as well) is slowly organizing just east of Hawaii. (WeatherFront)
What to make of this? Well, the system itself is trying to get organized near that little red “x” on the image above. It looks close to maybe becoming a depression, so we’ll see we get that today. We are about 4 days out from Hawaii impacts. Over the last couple days, the upper end intensity of this disturbance seems to have faded a bit in the modeling. It is having to fight off a good deal of shear, but that should ease up in the next couple days. Likely, we see a depression, then tropical storm by tomorrow or Friday. As it approaches Hawaii this weekend, we should expect some degree of heavy rain, flash flooding, and gusty, possibly damaging winds on some of the islands. There’s still ample uncertainty on the exact track and intensity, so specifics are tough to nail down.
Another potential risk is wildfire ahead of the storm as winds increase and humidity drops. This will be something to also monitor in the next couple days as this system organizes and approaches.
