The Eyewall

One-sentence summary

A disturbance in the north-central Atlantic presently remains the only area of note over the next 7 to 10 days, and it will not threaten any land.

Happening now: Mid-ocean madness!

That subheading is a bit dramatic, but it’s been quiet enough of late, so we’ll let that go. Anyway, as we gaze upon the open Atlantic between Bermuda and the Azores this morning, we can see an area of cloudiness and storminess sitting over that part of the world. Yesterday, it received the invest designation, meaning meteorologists have enough evidence to run some additional modeling on this area.

Invest 94L has about a 60 percent chance of developing over the next few days before it runs out of support in the open Atlantic. It will not threaten any land, and at worst, it should become a minimal tropical storm. Chaotic steering currents and a weak system will make 94L, whatever it becomes, susceptible to being bullied around, and as such, the potential track looks a bit like a horseshoe.

This type of track, odd as it seems, is not that uncommon in this part of the world. When storms develop out in the hinterlands of the basin, they can do weird things, because they are often and weak and just going to get pushed around by whatever influences exist at the time in those areas. We’ve seen storms do loop-de-loops, curly-Qs, stutter steps, somersaults (ok not really), and more. So, yes, it looks difficult to wrap your head around perhaps, but it’s not uncommon. That it is happening in mid-July does make it a bit uncommon, as we’ve discussed this week.

Anyway, over the next few days, 94L will possibly rev up, rev down, and eventually falter as it has to manage shear and cooler waters.

The medium-range (days 6 to 10): Nothing for now

There is nothing of note in the medium-range that we can see at this time. I will note, however, that one way to get a homebrew-type storm (a system that forms somewhat unexpectedly close to the coast) is to pile complexes of thunderstorms into the Gulf of Mexico. Over the next week or so, that’s sort of what we may see happen, as areas of thunderstorms meander around the eastern periphery of high pressure anchored over Texas and the Southwest.

As of today, I see no reason to think that any of this would form. But with enough “oomph” it becomes something to watch. For now, that’s not expected, but I at least want to point it out to you so you can see a little more of what we look at and why we don’t just rip and read models verbatum.

Fantasyland (beyond day 10): Let’s look way out beyond day 10

As of today, nothing is showing up out there in the distant future. Things look quiet into most of days 10 to 15 or so.

The ECMWF model recently completed a major upgrade that allows a 100 member ensemble to run once a day to produce a forecast 3 to 6 weeks out in time. In other words, it runs the model 100 times with various tweaks to produce various outcomes. One product it does produce out 3 to 4 weeks is a tropical cyclone frequency and accumulated cyclone energy (ACE) forecast. I try not to read too much into these, as they can be somewhat noisy. Just this week, they suggested more activity in weeks 3 and 4. But as of yesterday’s run, that had backed off.

Still, it’s a nice tool to have. It currently shows near average activity for weeks 3 and 4, sort of what I would have expected when looking at the bigger picture right now. That is not to say that things cannot get active in that timeframe, just that sitting here today, we don’t necessarily expect it to happen. There are some hints that later in week 4 or week 5 (mid-August), we may see the Atlantic develop a more favorable “background state,” which could lead to a more hospitable environment for tropical systems. We will see how that progresses forward in time. For now, rest easy and enjoy the quiet!

One-sentence summary

The majority of the tropical Atlantic will remain fairly quiet, however it appears increasingly possible that a tropical system could form several hundred miles east of Bermuda during the next week.

Happening Now: No worries for most

In the Atlantic this week all eyes are, improbably, on an area of low pressure located about 500 miles to the east-northeast of Bermuda. As Matt pointed out on Tuesday, historically this is a very unlikely place for a tropical system to form in mid-July. But as we’ll discuss a bit more below, this is not a normal year. The seas in the Central Atlantic Ocean are fairly warm for this time of year.

The National Hurricane Center gives this system a 50 percent chance of becoming a tropical depression or storm over the next seven days before it would likely fizzle out, moving further north into waters less favorable for development. Given that this system almost certainly will remain out at sea, it should ultimately be of little concern to to us in terms of impacts. Unless you’re a fish. Or run a shipping company.

The medium range (days 6 to 10): Let’s talk about the Gulf of Mexico

Beyond the system in the Central Atlantic, there’s not much to say in terms of activity. But that’s perfectly normal for mid-July, when there’s often a lull in the tropics. However, I do think the warm water that’s allowing the Central Atlantic system to form offers us a cautionary tale.

If we turn our gaze to the Gulf of Mexico, we see very high sea surface temperatures. If you live anywhere along the coast, from Brownsville, Texas to Miami, Florida, you’ve probably noticed the very warm nights this summer. This is due, in part, to temperatures in the Gulf of Mexico that are running from 1 to 5 degrees Fahrenheit above normal. This onshore flow adds to the overall mugginess of the air.

This is not a concern now for tropical activity, as wind shear remains fairly robust across the Gulf, inhibiting storm formation. But it will become a significant concern as we get into August and September, when wind shear tends to relax a bit. I’m not making any concrete predictions here, but with sea surface temperatures this warm, if tropical systems do form they will have the potential to become very strong, very quickly.

Fantasyland (beyond day 10): Still quiet

Fortunately, there remains no sign of anything notable in the extended range right now. This is likely to change as we get toward the end of July and into August, but for now things are quiet.

One-sentence summary

The majority of the Atlantic will remain fairly quiet, but the far north may see a weak system develop by the weekend that could gradually drift toward the Azores.

Happening Now: No worries for most

The Atlantic has some action out there today, but none of the systems at this point looks like a serious threat, and certainly nothing that would threaten any land. There’s a tropical wave in the islands today, bringing some showers and storms. A rather robust wave just emerged off Africa, but it’s already losing some steam.

But the main system we’re watching will come to fruition in the medium range, so we’ll get into that below.

All in all, things are currently quiet from an impacts standpoint.

The medium range (days 6 to 10): Can the North Atlantic do it?

When we look at formation points of northern Atlantic storms throughout history between July 11th and July 20th, one area we generally can usually rule out for storm origin is east of about 55°W longitude. We’re going to be watching exactly that area this week and weekend for potential development.

The National Hurricane Center has a 50 percent chance of development over the next week as of this writing. Curious and puzzling are words that come to mind, but when the Atlantic is as warm as it is, I guess this should not come as a shock. Whatever the case, we are watching this disturbance east of Bermuda in particular that will slide eastward over the next few days.

We can say a couple things about this system, should it develop. First, from the spaghetti plot below, which shows all the European ensemble members, 51 of them run with different tweaks in their starting points (to generate a more realistic spread of potential outcomes), we get a broadly north then east-moving system for several days. The map stops at day 7, and that’s a pretty wide dispersion of outcomes. In time, there’s also some chance the system meanders as far as the Azores, which could lead to eventual impacts there, though I’m not ruling that in just yet. But a fairly broad spectrum of potential track outcomes leads to above average uncertainty over the next 5 to 7 days.

The other thing you can say is that most modeling does keep this system on the lower end of the intensity spectrum. Wind shear and relatively “cooler” water should eventually take a toll on whatever this is and cap it at a reasonably manageable intensity. Again, if it develops.

A lot of ifs here, but it’s something. Certainly unusual and a curiosity. Thankfully it remains relatively away from land impacts. We’ll see how this goes in the days ahead.

Fantasyland (beyond day 10): Quiet

No sign of anything menacing us in the extended range right now. Modeling continues to non-specifically hint at some more activity in this timeframe, but there’s nothing we can hang our hats on and focus on showing up out there.

One-sentence summary

While tropical development is not expected over the next week or so, there are a couple features to keep tabs on in the Atlantic.

Happening now: Watching the Atlantic

After the weekend, we start the second week of July off with a couple items of note in the Atlantic. Just to be clear here, we aren’t necessarily expecting anything important to come from this, but given the warm ocean waters, it’s not the worst idea in the world to keep an eye on things.

Let’s start with the current picture of dust and disturbances.

You can see a pretty healthy area of dust stretching across the Atlantic from Africa to the Caribbean islands. Surely not the most impressive we’ve ever seen, but it’s definitely there. Anyway, most of the dust stretches across 20°N latitude until you get close to the Caribbean. Underneath that band of dust is a tropical wave. This has shown flashes of coherence through the weekend, and the European ensemble model in particular has at times latched onto this becoming A Thing over the next few days. Frankly, it’s hardly impressive looking today, likely battling some of the dust on its periphery and running into a wall of shear on its west side.

Modeling has gotten a good deal less excitable about this wave, so I don’t think it merits close watching, but we’ll see how it goes over the next day or two.

The medium range (days 6 to 10): Watching the far north Atlantic

Outside of that disturbance above, we had mentioned last week that the far north Atlantic might see some noise this week. Indeed, we have a pair of disturbances sitting up there. An actual surface low should develop in the coming days from the smaller area of storms at left on the image below (exiting Bermuda) and we may see this area become a development one.

The National Hurricane Center is assigning about 30% odds for that to occur. If it does happen, the system would likely meander somewhat incoherently, as if it were 2 AM and last call around the North Atlantic generally toward the Azores over time. We’ll see if it become a threat to those islands. For now, we’ll say this is not a big deal but does bear a little watching.

Fantasyland (beyond day 10): Mostly quiet

The good news is that despite the slight uptick in “noise” today, the day 10+ period does not look that interesting right now. Not to say that things will not change, but at this point, I’m not seeing much of anything that warrants a lot of our attention.

Sidebar: New England flooding

Flooding in New England is not uncommon. The region has a long history of flooding events, often with remnant tropical systems. But what is expected today, particularly without the involvement of a tropical system is troubling. That region is in line for some serious rain and flooding today, as a pipeline of moisture extends from the warm Gulf up through the warm Atlantic into New England.

The Weather Prediction Center has parts of northern New York and Vermont in their rare “high risk” category for excessive rainfall, which usually correlates strongly to bad outcomes. Significant to catastrophic flooding is expected in parts of New England and New York today because of this setup. Rainfall warnings extend into Quebec as well.

It’s also a good opportunity for us to look at sea-surface temperature anomalies and see just how warm things are right now.

There is hardly any cooler than normal water to be found anywhere in the Atlantic, Gulf, or Caribbean. This is one reason why it’s tough to forecast a slow hurricane season. At any rate, our thoughts are with the folks in New England that will be dealing with a very rough go of it today.