Never call it a bust: Hurricane season takes a late August siesta, so what’s going on?

Coming into this hurricane season, there were breathless forecasts calling for anywhere from 20 to even 30 named storms from some folks. Government forecasts were more conservative but even they were the most active we’ve ever seen from NOAA. Colorado State, too. So, as we sit here on August 21st with next to nothing showing up in modeling for the next 7 to 10 days, it’s reasonable for the general public to ask questions about those forecasts.

Back on day one of hurricane season this year, we published a piece about ways this hurricane season could essentially fail, or at least turn out “less bad.” We advertise ourselves as no hype, which as comments occasionally show has good elements and bad elements (we seriously thank you all for your support and readership — and constructive feedback only helps us to do better!). But the question was basically “Are we overhyping this season?” And the answer was no: All the elements that you would want in place for a historically active season were in place. All those big time forecasts were justified.

One of our potential fail modes was if La Niña developed too slowly. Indeed, the pace of the La Niña development this season, while uneven, has generally lagged the strongest projections. At least officially. Here’s a look at the May 1st European model ensemble outlook for the ENSO 3.4 region, the box of temperatures we look at to basically designate La Niña or El Niño.

The spring forecasts for La Niña have (to this point) turned out a little too aggressive. But directionally, they’ve been fairly correct. (ECMWF)

We should begin closing in on an official La Niña designation in the next month or two, but we aren’t quite there yet. Keep in mind, this is by no means a perfect representation of things, and sometimes the atmosphere can behave more Niña-like even if we aren’t officially there yet. But this has not developed as aggressively as some modeling showed in developing in spring.

So, at a very, very distant level, perhaps that has something to do with it. Michael Lowry, in his excellent daily newsletter pointed out yesterday that wind shear has become almost too extremely reversed this month. Typically, during a La Niña, there is more of an easterly component from the wind that counteracts or reduces the usual west to east winds that can cause shear in the Atlantic, detrimental to hurricane development. In a twist of fate, there’s so much of an easterly component to the upper level winds this year that it’s actually causing easterly shear. Otherwise, we might be a good bit busier at the moment. If you look at the basin as a whole since June 1st, winds have been generally lighter than usual in the Caribbean and much of the Atlantic and a bit stronger than usual in the southwest Atlantic and in the Gulf.

Upper-level winds have been generally below average this summer in some key tropical development areas. As such, we’ve accumulated some bang for our buck this season so far. (NOAA PSL)

Let’s dig a little deeper. One thing that’s legitimately fascinating to me right now is what’s happening in terms of upper level background support in the atmosphere. Using a variable known as velocity potential, we can see that in historically active hurricane seasons, you would expect to see a significant area of rising air in the Indian Ocean, bleeding a bit into Africa (green on the top map below). Opposite to that, there would be a significant area of sinking air in the Eastern Pacific Ocean (brown colors below). Why is this important? In order to generate an active outbreak of storms in the Atlantic, you need disturbances tracking across Africa, which tend to get supported by rising air over and just east of there. You also prefer to see the Pacific undergoing sinking air, as a way to keep it from ‘robbing’ the favorable conditions for storminess. Sinking air suppresses thunderstorm development and tends to dry out the air a bit.

So what’s going on right now? So far this August, we’ve actually *had* what we would expect from a hyperactive season in the Indian Ocean. Click to enlarge the image below.

A comparison of velocity potential in hyperactive seasons (top) vs so far this August (bottom). While we have what we’d expect for a period of high activity, something is out of phase inhibiting things. (Eric Webb/NOAA)

We have a ton of rising air in the Indian Ocean this month (purple & blue on the bottom map above). We have that extending into Africa. This is what you’d expect for a busy season. Where it differs, however is exactly where the sinking air (red/orange in the bottom panel above) is located. In a typical hyperactive season, this is focused over the Eastern Pacific. This year, it’s focused on the eastern side of South America. This is Matt speculating wildly here, but: I suspect that we’re seeing the right ingredients in place, but I think we are seeing them out of phase. The rising air in the Indian Ocean extends deeper into the Pacific, and there is more of a neutral Eastern Pacific signal right now. This is helping boost activity in the Pacific.

Today’s 7 day outlook in the Pacific includes Hurricane Gilma and two other disturbances that are likely to organize. (NOAA NHC)

The problem with the tropics is that support like this generally moves from west to east, and eventually this will change. So the quiet now may change in a very, very quick way come September when this (presumably) shifts. For now, the Atlantic is still seeing rampant dust and a slightly displaced intertropical convergence zone (ITCZ) which is sending disturbances off Africa too far north and into dust. So they die off earlier. This too will change.

Widespread Saharan dust (pink, red, orange) extends across much of the Atlantic, and as disturbances are coming off farther north than usual, they’re hitting the dust head on. (University of Wisconsin CIMSS)

In fact, if you look at the forecast of African Easterly Waves (AEWs) from the latest GFS model, you can see this southward shift approaching heading into the next week or two. The waves lined up over Africa are about 5 to 10 degrees farther south in latitude about 4 days from now, which means they will emerge farther south and in more of a traditional area less exposed to Saharan dust in late August and September.

Tropical waves are going to begin emerging off Africa farther south than they have been recently, which should ultimately lead to a boost in activity heading into September. (Quinton Lawton, University of Miami)

So, yes, things are almost certainly going to pick up soon.

Despite perception, this season’s current accumulated cyclone energy is running nearly 3 times higher than usual! We’ve amassed as much ACE so far this season as we’d typically see by the peak day of hurricane season (September 10th). We’ve done this on the backs of only five storms so far, three of which have been hurricanes, and one of which (Beryl) smashed early season records in the Caribbean and Atlantic.

Accumulated cyclone energy (ACE) this season has been historically high despite the perceived slow start to the season. (Kim Wood/University of Arizona)

So despite the perception that this season has been slow to start, it actually has not been. In fact, 2024 is in rarefied air in terms of ACE to date. This perception might have to do with storm inflation, or the idea that we are naming more storms today than we did, say, 20 or 30 years ago. In 2020, basically the benchmark for recent historically active seasons, today marked the formation date for Hurricane Laura, the 12th named storm of the season. Here we are in 2024 sitting at five, and it’s no wonder the perception is skewed. Despite having more than twice as many storms to this point in 2020, we only had half the ACE (26 vs. 55 this year). 2020 kept churning out mostly sloppy storms until Laura, and then things got nasty. We’ve had three legitimate hurricanes this year and only about one “throwaway” storm (Chris). The takeaway message here is that: We can make up ground in September very, very fast. Very fast.

So, no, this season’s extremely active hurricane seasons have not been a bust so far, and they probably won’t end up being a bust overall. We’ve had a “bang for our buck” season so far with quality storms over quantity as, say, in 2020. And while we are in a lull now, the setup is probably going to change in 7 to 10 days to allow things to crank up in September. Never call it a bust. If it is one, we can discuss why in November. For now, use this quiet time to review your hurricane preparedness plans and supply kits. And stay tuned here for the latest through September.

Ernesto exiting, as the Atlantic tropics should settle down for a bit now

Headlines

  • Ernesto will exit out to sea tonight and tomorrow, brushing southern Newfoundland with some impacts on the way out.
  • The Atlantic looks quiet through early next week.
  • If we want to scope out trouble that isn’t showing up on models, we’ll watch a Gulf disturbance this weekend and early next week; unlikely to develop but will bring some welcome rain chances back to Texas.

Ernesto finds the exit ramp

After impacting Bermuda and sending a bunch of rough surf toward the Atlantic coast of the U.S. and Canada, Hurricane Ernesto is on the way out the door today.

Hurricane Ernesto is accelerating off to the northeast, while flinging clouds and perhaps some modest impacts to southeastern Newfoundland. (Weathernerds.org)

Ernesto is now moving northeast at 28 mph and taking on that “look” of a storm in transition from tropical system to post-tropical low pressure. Winds are 90 mph with Ernesto, and the wind field remains large, with tropical storm force winds expanding out 220 miles from the center. As Ernesto makes its closest pass to Newfoundland tonight, wind, rain, and rough seas will likely impact the Avalon Peninsula.

Ernesto’s track will bring it close to the Avalon Peninsula of Newfoundland tonight before it exits out to sea. (Canadian Hurricane Centre)

With Ernesto moving along quickly, conditions should deteriorate there quickly tonight, then improve quickly tomorrow. By tomorrow night, Ernesto should be full extratropical/post-tropical and racing east-northeast across the Atlantic. And that closes the book on the fifth storm of 2024.

A lull for a moment

The Atlantic basin will shut down post-Ernesto for a moment or two. Or three. Who knows. Tropical activity over the next 7 days is expected to be basically non-existent.

A plot of European ensemble tropical systems over the next 7 days shows virtually nothing after Ernesto. (Weathernerds.org)

How long this lull lasts is tough to say. We’ll dive more into the context of all this and how this season stacks up vs past seasons a little later this week (and key reasons to not write it off as a “bust” in mid-August). For now, I don’t see anything really of note out there over the next 7 to 10 days. I do believe conditions will shift more favorable for activity as the calendar flips to September. But that’s an average confidence feeling right now.

If we want to dig for trouble that could surprise us, we could maybe look in the Gulf this weekend or next week. It appears that a disturbance is going to swing in either off the Atlantic or from inland thunderstorms across the Southeast and into the northeast Gulf of Mexico by this weekend. From there it will follow its way around the periphery of a Central Plains ridge of high pressure across the Gulf toward Texas.

Mid-level disturbance may be worth watching as it swings across the Gulf this weekend or early next week. Not expected to develop, but it should bring increasing rain chances to Texas next week. (Tropical Tidbits)

Again, we’re looking for surprise trouble here, which is to say that no model currently develops this at all. And that’s the most likely outcome. But, we’ll keep tabs on it just in case. Regardless, this will probably bring an increase in rain chances to Texas next week, which has gone fairly dry this month. Most rain will be welcome.

But aside from that, I think we’re on a pre-peak break in the Atlantic through early next week. We’ll take it.

Ernesto approaching Bermuda, and it will fire off rough seas and dangerous rip currents on the East Coast this weekend

Headlines

  • Ernesto now beginning to bear down on Bermuda.
  • Heavy rain, strong winds likely well into tomorrow there, as Ernesto slows down and crawls past.
  • Ernesto will brush Newfoundland on the way out to sea next week.
  • Dangerous rip currents likely up and down the East Coast this weekend with Ernesto’s large size and waves.

Ernesto on approach to Bermuda

Hurricane Ernesto is now a category 2 storm, with maximum sustained winds of 100 mph — probably. Ernesto is not the healthiest hurricane we’ve ever seen, but it’s a large one.

Ernesto is clearly feeling the presence of some wind shear and maybe a little lingering dry air as it approaches Bermuda. (Tropical Tidbits)

Ernesto is loaded with moisture, and the wind field is enormous. Tropical storm force winds extend out 275 miles from the center. What Ernesto may lack in intensification it more than makes up for in size. Conditions are beginning to go downhill on Bermuda this afternoon, and that will continue into tonight, as evidenced by a lot of rain (and embedded wind) showing up just south of the island.

Radar snapshot of Ernesto’s rains closing in on Bermuda this afternoon. (Bermuda Weather Service)

So even if Ernesto weakens over the next day or so, it will pack plenty of punch on Bermuda, particularly due to the duration of the storm. Ernesto will slow down a good bit through Sunday before picking back up forward speed and accelerating out to sea and weakening once more.

Ernesto will move sluggishly through Sunday before picking up a lot of forward speed Monday and Tuesday and accelerating out to sea. A close brush with Newfoundland cannot be ruled out. (NOAA NHC)

As Ernesto passes Newfoundland, likely just to the south, some impacts are possible there as well, though they would probably hit and exit quickly. Tropical storm force winds and locally heavy rainfall are the main concerns.

In addition to Ernesto as a hurricane, we continue to advertise the extremely rough surf and rip current risk up and down the East Coast that’s expected this weekend. With a wind field of 275 miles, you can bet that Ernesto will be churning out some waves. Dangerous rip current risk will be moderate to high along virtually the entire East Coast by tomorrow and Sunday.

A significant rip current event is likely this weekend on the East Coast due to Ernesto’s large size and waves. (NWS Morehead City)

We again urge folks to use caution in the water this weekend.

Behind Ernesto, we continue to advertise calm for next week. We’ll talk more about that next week and assess when it could change.

Hurricane Ernesto being challenged by some dry air as it plots a course toward Bermuda

Headlines

  • Hurricane Ernesto prompts Hurricane Warnings for Bermuda as it tracks in that direction.
  • Look for somewhat prolonged wind, surf, and rainfall impacts in Bermuda beginning tonight into Friday.
  • Ernesto is large in size and will generate rough surf and dangerous rip currents far from the center along the U.S. East Coast heading into the weekend.
  • Impacts are possible in Atlantic Canada Sunday or Monday, particularly in Newfoundland as Ernesto comes north and accelerates out to sea.

Ernesto struggling a little this morning

Hurricane Ernesto is moving along, north around 14 mph this morning over the Atlantic. A look at Ernesto on satellite tells the story pretty well.

Ernesto is dealing with dry air as indicated by some of the gaps in colder cloud tops (red/orange) in the inner core of the storm. (Tropical Tidbits)

It’s pretty clearly fending off some dry air. It’s also a bit of a larger storm in size, with tropical storm force winds already extending out 175 miles from the center. The combination of Ernesto’s size and some of that dry air wrapping in is keeping a lid on much intensity gain today. The current maximum sustained winds are around 85 mph.

Ernesto’s track forecast

Ernesto is about 570 miles south southwest of Bermuda. Ernesto is going to take a weird track of sorts over the next 3 days or so, off to the north northeast, then northeast, then perhaps bending back north a bit. This is all due to steering currents that will be pushing Ernesto around. As I noted yesterday, the first trough will try to grab Ernesto and force it off to the northeast toward Bermuda. But as Ernesto approaches Bermuda, it will slow down and begin to turn back north somewhat as that trough exits. This will lead to a very close approach with a direct hit on the island. Regardless, hurricane conditions are likely to impact Bermuda by late tomorrow or Saturday, and a Hurricane Warning is in effect there.

The upper level map and approximate location of Ernesto every 12 hours through Monday evening as forecast by the 51 member European ensemble mean. (Tropical Tidbits)

Beyond Bermuda, Ernesto will likely resume a slow northward movement in between two troughs. The next one moving in from the Great Lakes will try to also “grab” Ernesto, but it will also be following the steering currents around high pressure between Bermuda and the Azores. Thus, we should see Ernesto resume a slightly faster north northeast or northeast motion. Whether this happens fast enough to avoid a collision with Newfoundland remains to be seen. This will probably pass east of Nova Scotia and Prince Edward Island, however. Still, it’s likely that Atlantic Canada will see at least some impacts from Ernesto as it passes by, including gusty winds, rough seas, and perhaps some heavy rain.

Ernesto’s intensity and impacts

In terms of intensity, Ernesto should continue to slowly strengthen over the next day or two as it approaches Bermuda. Depending on how much it can whittle away the dry air, it may approach major hurricane intensity before passing close to or over Bermuda. It’s also worth noting that the slowing forward motion as it approaches Bermuda will likely prolong some of the wind, rain, and surge issues on the island. So even if this comes in a bit weaker than forecast, it may punch above its weight class given the slow movement and prolonged impacts. Bermuda is no stranger to hurricanes, but folks should take this one seriously.

Strong rip currents and rough surf will be likely this weekend on the East Coast of the U.S., likely leading to dangerous swimming conditions at times. (NWS Newport/Morehead City)

In addition, on the East Coast of the U.S. rip currents are going to become an issue heading into the weekend as Ernesto passes offshore, especially given the large wind field of Ernesto. Please follow all posted signs and flags at the beach this weekend. Rip currents are deadly, with nearly 30 deaths so far this year from them.

Ernesto should be out of the picture after next Monday or so, followed up by a period of calm Atlantic tropics. There may be some signs of life very late on model runs in the far eastern Atlantic, but we’ll see.