Maybe we can get something going in the Atlantic? Plus, an anatomy of another southern Connecticut flooding event

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In brief: Today we update on a disturbance east of Bermuda that is flailing a bit and has a low probability of development. We also take a deep dive into the flooding that hammered southwestern Connecticut on Sunday.

Tropical Atlantic

We begin today in the Atlantic, where the odds of open Atlantic tropical development have waxed and waned over the last few days, and in very 2025-26 fashion, they seem to be struggling mightily.

An early AM satellite view of the Atlantic disturbance east of Bermuda. (WeatherFront)

On satellite, you can see that this thing is not even challenging invest status right now, let alone heading for development. Over the next few days, the disturbance behind these clouds will drift west, inching toward Bermuda. Any development risk is very low and would almost certainly be very slow initially. Wind shear in the area is fairly low, but this disturbance is fairly broad in size and just does not seem really able to congeal around a tighter center in the modeling.

Google Deep Mind’s WeatherNext3 model has about a 20 percent or so chance of development. (Google)

Google’s WeatherNext model still does hold out some chance it can do something, with about 20 percent or so of the members of WeatherNext 3 showing development. The larger 1,000 member ensemble shows about 40 percent odds of development. It’s somewhat notable that the ensemble members that do develop this system in many cases make it a stronger one. So, I think the points here are: This is unlikely to impact land, the chances of development remain in the 20 to 40 percent range, and if it can develop, it has potential to become a stronger storm. We’ll keep watching for educational purposes.

What else?

You had to ask? The answer is nothing. Right now. I will say we are beginning to see some “noise” in various ensemble members that suggest something could be afoot near the Gulf or in the deep Atlantic at some point over the next 10 to 14 days, but there is nothing specific we can zero in on right now. So at this point, it’s the meteorological equivalent of uncorroborated information. We will keep watching and get more specific if and when the need arises.

Anatomy of another Connecticut flooding event

This summer was the wettest on record at the primary observing site in southwest Connecticut, in Bridgeport. By about an inch, 2026’s 21.24″ in Bridgeport bested 1972’s 20.23″ for wettest summer since 1948. We just added the 13th wettest day on record this past weekend, when Bridgeport recorded 4.25 inches of rain over the course of about 3 to 4 hours. Some parts of Fairfield County and east of New Haven were hit even harder.

Radar estimated rainfall from Sunday in southwestern Connecticut. (WeatherFront)

Stamford reported 7.47″ of rain, while just east near Darien, we had a 7.40″ report, and a 7.19″ report east of Norwalk in Westport, which was particularly hard hit. This is now the second significant flash flooding event since I moved here this summer. So you can say I am to blame, I suppose. But in all seriousness, this is not a laughing matter, and the Northeast has been a magnet for increasingly intense rainfall in recent years. 2026 is now the record holder in Bridgeport for number of hours that saw 1 inch of rain in an hour or more, at 5 of them. Folks on the Gulf Coast will read this and say “That’s cute,” but here in the Northeast, once you hit 1 inch per hour, that’s when serious problems can begin. Two of those hours came during the major January winter storm, another occurred on July 21st, a fourth on August 23rd, and the fifth on Sunday.

The two big ones on Sunday and back in July came as something of a surprise, in the sense that “Wow, I didn’t realize it rain that hard for that long.” But also in the sense that forecasts weren’t necessarily calling for 7 inches of rain. Even as the rain began Sunday morning, the NWS in New York City had called for locally higher amounts of 3 to 5 inches of rain in southern Connecticut. And a flood watch was indeed in place and had been for many hours prior to the onset of rain. The area was under a slight risk (level 2/4) for excessive rainfall.

(NWS New York City)

We have been under several flood watches this summer and 10 so far this year (compared to 5 in 2025 and 11 in 2024), so there may be an element of fatigue settling in, or the fact that it was on a weekend when folks were a little less tuned in may have also contributed to the surprising element. But short of underdoing the peak forecast totals a little, this was a pretty decent forecast. And there was good reason to believe that 5″+ totals were a distinct possibility in this area ahead of time.

Why is that? First, let’s look at the HREF/REFS details. The HREF probability matched mean product, which I have spoken highly of, showed 5 to 7 inches of rain possible over Long Island Sound on Saturday morning’s 12z run.

HREF Probability matched mean total rainfall from Saturday morning’s forecast. (NOAA SPC)

The max total of any one forecast in the ensemble did exceed 7 inches. Corroborating this was the REFS model which showed a healthy probability of 5 inches or more of rainfall over the same area highlighted above. So at the least, looking at this, some other data, and subsequent runs, it was evident that someone could see 5 inches or more of rainfall and they’d probably be adjacent to Long Island Sound.

You could have also looked at the NWS’s experimental urban rain rate dashboard (URRD) and seen at least some hints of a somewhat significant flooding event possible. While no point forecasts are available for southwest Connecticut, the Port Jefferson, Long Island location would have been helpful and instructive in this case.

A screenshot of the URRD from Saturday morning for Sunday’s rain event. (NOAA)

What can we pick out on here? Well, if we look at 6 hour rain totals, we can see that the ensemble probability of seeing a 6 hour average rainfall recurrence interval (ARI) of 10 years was significant. And even looking at the chart on the bottom left, there were several members of the plume in the 10, 25, or 50+ year ARI. The 10 year corresponds to about 3.4 to 4 inches over 6 hours. 50 to 100 year recurrence intervals would be between 5 and 6 inches. What ultimately fell was closer to a 200 to 500 year ARI. What does that mean in normal person language? It means that the rains that fell on Sunday typically only occur every 200 to 500 years in basically a static climate (based on NOAA Atlas 14 data which came out for New York and Connecticut over 10 years ago). We know that the climate is warming and able to hold more water vapor than when these ARIs were calculated, thus the true ARI is probably less than that by several years.

But the takeaway here? Modeling did an adequate job of predicting both the scope, coverage, and intensity of the rain if you were willing to buy in. Easier said than done sometimes, but I’d argue these tools do a pretty solid job in most instances. While the placement was imperfect, I can tell you as someone who lived in Houston for 14 years, it’s hard to do much better than that.

Scanning the Atlantic for any whiff of activity and still mostly struggling

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In brief: The Atlantic is in a very, very quiet place tropically, and that should mostly continue. There is some potential for an open Atlantic system out there in a week, which we discuss below.

It’s September 12, 2026, and for the hurricane season to date, in terms of accumulated cyclone energy (ACE), the Atlantic is running at 7 percent of normal to date. Not for the entire season, for the season so far. We’ve blown past 1915’s 2.53 ACE to sit at 4.4. So, as far as we know, it’s not the least active ever. But in the modern era, we’re not even close.

Accumulated cyclone energy today is currently obscenely low for the season. (Colorado State)

1983’s 17.4 ACE is the modern value that’s being challenged. One storm can blow this out, but at this point, we’re sitting rarefied air.

It is literally the opposite in the Eastern Pacific which is sitting at over 190 percent of normal activity to date. If the season ended today, it would be the 12th most active on record. Thus, we’ll be challenging some big years.

So where do we go from here? The next item to watch will be a potential disturbance in the middle of the Atlantic Ocean, several hundred miles east of Bermuda in about 5 to 7 days. Models are somewhat mixed on exactly how things go here, but Google’s Deep Mind model is fairly aggressive in developing this one.

A number of Google Deep Mind ensemble members develop a system in the open Atlantic near or east of Bermuda in about a week or so. (Google)

Obviously we can’t say a whole lot about this right now given the model dispersion of outcomes and the lack of a genuine disturbance to really track at this point. But it does appear that whatever this is won’t bother the Gulf or Caribbean. However, folks in Bermuda may want to keep tabs on this. Some of the model ensemble members do develop this one a little more aggressively than others. So perhaps this is a candidate for our first true textbook storm of the season. It’s not abnormal to see stronger storms in the higher latitudes of the Atlantic in El Nino summers. Let’s see where this goes.

Beyond that, there is next to nothing in modeling to zero in on over the next 2 weeks. Generally speaking, if something were to develop, it would probably have to be courtesy of a dying cold front in the Gulf of Mexico or off the Southeast coast. We don’t see any meaningful sign of that right now.

Enjoy the weekend!

Monday Miscellany: Lowell, an Atlantic update, and a look at a Cape Breton Island flood

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In brief: Hurricane Lowell will impact Hawaii over the next 24 to 36 hours, perhaps significantly so west of Oahu. The Atlantic remains quiet. And we take a deep-ish dive into a squirrely, significant Atlantic Canada flooding event.

Hurricane Lowell

Hurricane Lowell is heading toward the western Hawaiian Islands, with its center likely to track a bit closer to Ni’ihau than we discussed on Saturday, only about 40 miles or so west of the island and with a wider eastern flank, capable of producing strong winds on Kauai and even perhaps Oahu. Thankfully, Alan Gerard at Balanced Weather has an excellent summary of the impacts and details on Lowell to check out. I’ve done this long enough to know that sometimes, you don’t need to reinvent the wheel!

(NOAA/NHC)

Atlantic Basin

We continue to see no sign of any meaningful tropical activity in the Atlantic for the next 7 to 10 days. Yesterday’s Euro subseasonal outlook gave us 20 percent of normal activity or less over the next 2 weeks.

The Pacific should rage on while the Atlantic remains quiet. (ECMWF)

If there is any risk over the next week or so, it would be on the lower end of the scale in the northwest Gulf of Mexico. A weak but slow moving mid-level disturbance is likely to generate showers and thunderstorms near the Texas and Louisiana coasts this week. In about 95 percent of cases like this, nothing happens. but in the off-chance that a complex of storms happens to form near the coast and drift offshore, it wouldn’t be out of the realm of the possible to see it try to develop a surface low.

A mid and upper level low pressure system will hang near the Texas and Louisiana coasts later this week. (WeatherFront)

Again, this is highly unlikely to do anything except bring unsettled weather back to Texas and Louisiana, but it’s the time of year where you just tap back in a few days from now to make sure nothing’s changed.

Otherwise, I can’t really sniff anything else of note out.

Cape Breton flooding

Thank you to reader Alison for flagging this one. A pretty intense storm hit parts of the Canadian Maritimes this weekend, specifically Cape Breton Island and parts of the northeast mainland of Nova Scotia. How much rain has fallen in the last 72 hours? A lot.

Totals as high as 12 inches (300 mm) fell on parts of Cape Breton Island. (NOAA)

A gauge at Ingonish Harbour on the south coast of the Cape Breton Highlands picked up over 12 inches of rain (300 mm), while another gauge measured over 11 inches (280 mm) at North River Bridge. Many locations saw 6 to 9 inches (150-230 mm) of rain across Cape Breton.

The rain fell in two bursts, one on Friday, followed by a heavier one on Saturday. Some places saw additional rain on Sunday as well. The culprit was a slow moving upper low that basically cut off from the jet stream and sat over Nova Scotia this weekend. Interestingly, the GFS model had forecast upwards of 150-200 mm of rain on Thursday night into Friday morning, so a signal for torrential rain was there. Whether or not you wanted to trust it was another matter. The usually more trustworthy European model had significantly underforecast rain, especially on Cape Breton Island.

Friday morning’s GFS model rainfall forecast for this weekend did an admirable job over Nova Scotia and Cape Breton Island. (Tropical Tidbits)

The European AIFS model did better than its physics-based counterpart. That is also interesting because the line on AI modeling is typically that it cannot capture the tail (extreme) events. While it still underdid the rainfall this weekend, the AIFS did a much better job than the European operational model. It’s tough to get a good handle on how Google’s new AI model did with minimal available data still, but their WeatherNext 2 performed better than the AIFS, though not as good as the GFS.

Bottom line: This was a marginally predictable event. Upper lows can notoriously cause locally heavy rainfall under the wrong circumstances. And looking at a sample of radar data from Nova Scotia, you can see how this event was playing out at 4:30 AM local time.

Radar capture from Saturday morning in Nova Scotia around 4 AM Atlantic Time. (RadarScope)

A surface analysis from the same time shows a somewhat convoluted pattern over Cape Breton Island, with winds broadly out of the northeast or east, but varying levels of some convergence boundaries showing up on the map. It’s not exactly a grab your attention sort of map in real-time, but in hindsight, I can see how this may have aided this particular rain event.

A surface map around 3 AM AT on Saturday shows subtle boundaries that may have aided in storm redevelopment over Cape Breton Island. (NOAA)

But nothing appeared necessarily extreme about this event. Precipitable water levels were somewhere in the 85th-ish percentile, which while high is not exactly extreme. The only other thing I can point to is that water temperatures in this part of the Atlantic are running quite warm. So perhaps that also played a role. The Environment Canada rainfall warnings called for 80 to 120 mm of total rain on Thursday and 100 to 150 mm of rain by Friday evening. Again, it was predictable to a point, but it does appear that some subtle influences took this from a heavy rain event to a pretty bad flooding event. Thoughts with all those impacted.

Lowell will impact the western Hawaiian Islands after Labor Day while Marie flings some rare September rain toward SoCal

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In brief: Hurricane Lowell may not be a direct hit on Hawaii, but it will still deliver some noteworthy impacts to the western Hawaiian Islands after Monday. Hurricane Marie is going to fling some moisture for a rare September rain in LA and SoCal this weekend as well.

Hurricane Lowell

Lowell is a powerful, high-end major hurricane with 150 mph maximum sustained winds near the center. It is modestly imperfect, however, as some dry air or modest wind shear has eroded parts of the center’s thunderstorm activity a little bit.

(WeatherFront)

Still, Lowell is about as formidable as they get in this part of the world. Lowell’s forward speed, as expected is beginning to slow a bit, and it’s moving just north of due west. As ridging gets eroded by an approaching mid-level area of low pressure, Lowell will turn more to the north or even north northeast for a time. That trajectory will determine how close it passes to the western Hawaiian Islands.

Google Deep Mind’s operational model takes Lowell about 60-80 miles west of Ni’ihau or about 75 to 100 miles west of Kauai. (Google)

Per the most recent operational run of Google’s WeatherNext cyclone model, the track is slightly to the east of some other guidance, with a few outlier ensemble members taking Lowell within about 75 miles of Kauai and not far west of Ni’ihau. This would place those islands on the east flank of the storm, the stronger side, though perhaps far enough east of the center to avoid severe problems. Still, heavy rain is a possibility, and the current forecast calls for up to 10 inches of rain on Kauai.

Heavy rain is likely on Kauai and Ni’ihau. (NOAA WPC)

Confidence drops off some to the east of there, with the other islands more likely to see perhaps 1-4 inches of rain, with higher amounts in the southern facing slopes of the Big Island and Maui. The current forecast says perhaps up to 10 inches, but that may be a bit high depending on how close or far Lowell ultimately tracks.

Lowell is expected to be a borderline major hurricane when making its closest pass to the western islands. So, obviously strong winds are a concern. However, with Lowell passing just far enough west, it may mean the difference from some isolated damaging winds in the westernmost islands or something more serious. Obviously, the exact final track of Lowell is critical here in determining how strong those winds are. The HAFS-A forecast below takes the center about 40 to 50 miles farther west than perhaps it will go, so some of those stronger winds (yellow shading) will come very, very close to Ni’ihau and Kauai.

HAFS-A model wind gust forecast for Tuesday night’s close pass of Lowell. (WeatherFront)

Folks in Hawaii, especially on the populated Kauai should be following the advice of local officials and emergency managers. Presumably most hotels and resorts have plans for these scenarios as well, so heed their guidance too.

The rest of the tropics

Elsewhere, Hurricane Marie is not a threat to land directly, but some moisture is going to fling off it and toward southern California, especially in the Los Angeles area. This outward band of rain could produce around a tenth to a quarter-inch of precip across SoCal, even into the desert. Slightly higher totals are possible in the San Gabriel or San Bernardino Mountains. While that may not sound like much, consider that this is about 750 percent of normal. In other words, it does not usually rain in SoCal in September!

An unusual smattering of rain is likely Sunday into Monday in SoCal. (WeatherFront)

In addition to the rain, surf conditions are going to be a little nasty for the average person. Watch for coastal flooding, rip currents, and the high surf. Hopefully the surfers find ways to enjoy this.

Elsewhere, the Atlantic looks to remain quiet through all of next week.