2024 Atlantic Hurricane Season

ldub23 · August 17

1 hour ago, CurlyHeadBarrett said:

Precursor to possible Fran? (Fran is a nickname for Francine)

Past Labor Day. Probably less than the intrepid tropics follower would expect to see on an ensemble in a season that was supposed to be average, not to mention a 25/12/6 season

Floydbuster · August 18

5 hours ago, Silver Meteor said:

Charley Part II

My first full year in North Carolina, Wilmington was my new home after leaving Maryland. Then a Cat 1, Charley was a direct hit with the eye passing overhead. The front half eye wall was solid and easily visible from my apartment while the right rear, fully open with lots of blue sky, was oddly enough the strongest part of the storm. I saved a radar image from the time:

That image is Hurricane Ophelia.

Silver Meteor · August 18

20 hours ago, Floydbuster said:

That image is Hurricane Ophelia.

Aha! That does make sense. Ophelia came later and was a good one that had much better shape. The eye wall took all afternoon to move through. I have very few images of storms from Wilmington but possibly this one is Charley? I remember clearly the front half was very weak, so weak in fact I was wondering where in the heck is this hurricane? It was the backside right rear that had all the power. (I've no idea what that squiggle is on the image.)

NorthHillsWx · August 19

2 hours ago, Silver Meteor said:

Aha! That does make sense. Ophelia came later and was a good one that had much better shape. The eye wall took all afternoon to move through. I have very few images of storms from Wilmington but possibly this one is Charley? I remember clearly the front half was very weak, so weak in fact I was wondering where in the heck is this hurricane? It was the backside right rear that had all the power. (I've no idea what that squiggle is on the image.)

That looks like Florence. Charley was pretty much open on S side in the Carolina’s. Your squiggly is probably it’s motion or lack thereof

yoda · August 19

https://x.com/AndyHazelton/status/1825536397224100212

Seminole · August 19

12 minutes ago, yoda said:

https://x.com/AndyHazelton/status/1825536397224100212

Lots of dry air preventing development in the MDR.

ldub23 · August 19

1 hour ago, Seminole said:

Lots of dry air preventing development in the MDR.

Sort of surprising CSU didnt drop their numbers in half

GaWx · August 19

If the GFS/Euro end up verifying well, there could be as many as 4 straight Tahiti SLPs of 1019+ during Aug 19-22. I’d be very surprised if there isn’t at least one. Keep in mind that higher Tahiti pressure is favored during developing La Niña. There hasn’t been even a single day of 1019+ since 2010!

Tahiti SLP 1019+ since 1991:

1019.55: 1994 (Aug)

1019.1, 1019.44: 1996 (June)

1019.3: 1998 (Aug)

1019.28: 1999 (Aug)

1019.24: 2010 (July)

1019.44, 1019.61, 1019.78, 1019.59, 1019.14: 2010 (Sep)

1019.05: 2010 (Sep)

-So, there have been only 13 days of Tahiti SLP of 1019+ over the last 33 years with the record high being 1019.78 (Sep of 2010).

- This shows there’s been only one time when there were more than two days in a row of that (Sep of 2010). That was during the longest streak on record, 5 days.

- This shows that all were during June-Sep with a mean date of Aug. That makes sense because that’s during their winter, when sfc cold high pressures are at their highest SLP of the year.

- There is a decent correlation between high Tahiti SLP periods and an active Atlantic tropics mainly 1-3 weeks afterward. That jibes well with the idea of an active Atlantic sometime between very late this month and mid Sep.

yoda · August 19

Torch Tiger · August 20

7 hours ago, Seminole said:

Lots of dry air preventing development in the MDR.

Not a "huge deal" as not atypical for August, but if not washed out sooner than later it'll definitely put a damper on any big #'s

Windspeed · August 20

One of the larger WAM-anchored disturbances that I can recall in recent years will be moving off of WA. It will be interesting to see how modeling picks up on this feature late week. Does the low-latitude portion of the surface trough axis persist or the northern low that appears to be waning in convection?

GaWx · August 20

Probably not worth that much but fwiw the last 4 Euro-AIFS suggest the area around Puerto Rico may have to watch for a nearby TC ~Sep 3. Again, fwiw.

Will be interesting to see what todays Euro weeklies show after yesterday’s sudden pretty sharp downturn (ACE fell to 28 from 40, which is about where it had been for 7 days) for 3 weeks ending mid Sep. So, it still had some activity but was BN. Was that just a blip?

The 6Z GEFS is pretty active with many members having a TC in the W basin late.

MANDA · August 20

13 hours ago, Torch Tiger said:

Not a "huge deal" as not atypical for August, but if not washed out sooner than later it'll definitely put a damper on any big #'s

The big number threat is going by the boards. Not likely anything named next 7 days and maybe 10. That leaves a lot heavy lifting for September and October to get to 20 much less low or mid 20's. Highly unlikely at this point. Not to say we don't have some high quality Tropical Cyclones over the next 8 weeks.

jpbart · August 20

44 minutes ago, MANDA said:

The big number threat is going by the boards. Not likely anything named next 7 days and maybe 10. That leaves a lot heavy lifting for September and October to get to 20 much less low or mid 20's. Highly unlikely at this point. Not to say we don't have some high quality Tropical Cyclones over the next 8 weeks.

I suspect the season might be more back loaded into November, December than usual. A few storms my pop up then in a similar fashion as late June, July?

cptcatz · August 20

Last two GFS runs finally had something to look at long range. Maybe we'll see more stuff pop up on today's runs. Kinda crazy that it's August 20 in a forecasted hyperactive season and there's basically nothing on the horizon. I definitely can see october being busy based on the last 5 or so years.

Torch Tiger · August 20

4 hours ago, GaWx said:

Probably not worth that much but fwiw the last 4 Euro-AIFS suggest the area around Puerto Rico may have to watch for a nearby TC ~Sep 3. Again, fwiw.

Will be interesting to see what todays Euro weeklies show after yesterday’s sudden pretty sharp downturn (ACE fell to 28 from 40, which is about where it had been for 7 days) for 3 weeks ending mid Sep. So, it still had some activity but was BN. Was that just a blip?

The 6Z GEFS is pretty active with many members having a TC in the W basin late.

Yeah I'd be a bit surprised at mid-20's now but 20 seems doable, with a strong finish plus a few throwaways later this fall.

GaWx · August 20

12Z GEFS: another GEFS that looks rather active for first few days of Sept.

GaWx · August 20

CSU outlook for next 2 weeks (8/20-9/2): most likely near normal with activity more concentrated in 2nd week as one would expect based on models; no surprises in this. They did well with their prior 2 week fcast, which verified mainly due to Ernesto with its favoring of above avg activity:

https://tropical.colostate.edu/Forecast/2024-0820.pdf

GaWx · August 20

Euro weeklies mean ACE forecast update vs norm last 7 days (newest far right, which is 0Z of Tue):

8/26-9/1: 50%/60%/50%/50%/50%/30%/20%; Norm 14
9/2-8: 110%/110%/120%/100%/110%/70%/70%; norm 15
9/9-15: 90%/80%/90%/80%/100%/80%/90%; norm 16
9/16-22: 90%; norm 13

So, in today’s Euro Weeklies update regarding the 3 weeks I’ve been following, yesterday’s progged sharp mean ACE drop from 40 to 28 was maintained today. Also, todays added a new week (9/16-22) with a mean of 12 ACE.

Thus, today’s Euro Weeklies mean ACE prediction for the 4 week period 8/26-9/22 is 40. This 40 compares to the 1991-2020 avg of 58. So, mean ACE prediction is significantly below the 1991-2020 avg mainly due to weeks 1-2 fwiw.
Thoughts?

https://charts.ecmwf.int/products/mofc_multi_tcyc_family_frequency/overview/base_time?base_time=202408200000&parameter=Accumulated cyclone energy&valid_time=202409020000

StantonParkHoya · August 21

10 hours ago, MANDA said:

The big number threat is going by the boards. Not likely anything named next 7 days and maybe 10. That leaves a lot heavy lifting for September and October to get to 20 much less low or mid 20's. Highly unlikely at this point. Not to say we don't have some high quality Tropical Cyclones over the next 8 weeks.

The thing about October storms is they’re so much more likely to recurve with trough frequency picking up. So sure, fish watching could be good.

Kevin Reilly · August 21

1 hour ago, StantonParkHoya said:

The thing about October storms is they’re so much more likely to recurve with trough frequency picking up. So sure, fish watching could be good.

Explain Sandy then? October 22nd to November 2nd. My avatar by the way is the satellite of Hurricane Sandy. Don't forget about Ophelia as well. It's all about timing and later on tropical systems can be capture or run up along troughs.

Floydbuster · August 21

On 7/28/2024 at 6:53 PM, Floydbuster said:

One month from today I am guessing we will have a major hurricane threat for landmasses in the Western Atlantic.

Sticking to this. In 7 to 8 days, we will be a tracking a system that will be a major hurricane threat.

Normandy · August 21

To be fair it is august 20th. The bears have a reason to howl right now. My fear is when the lid comes off, it will be frightening (multiple major hurricanes threats at once)

cptcatz · August 21

10 hours ago, StantonParkHoya said:

The thing about October storms is they’re so much more likely to recurve with trough frequency picking up. So sure, fish watching could be good.

Not really. Maybe in the MDR but October is when development pushes west in the Caribbean and GOM. Look at Wilma, Sandy, Michael, Matthew, Delta, Zeta.

GaWx · August 21

34 minutes ago, cptcatz said:

Not really. Maybe in the MDR but October is when development pushes west in the Caribbean and GOM. Look at Wilma, Sandy, Michael, Matthew, Delta, Zeta.

- I believe that Oct is the most dangerous month for a direct landfall on the Gulf coast of FL.

- Up here in E GA, Matthew in Oct of 2016 was easily the worst since at least David (1979).

- Hazel in Oct of 1954 was one of worst ever in NC/SC and then was a monster well inland in much of E US

- Oct of 1898 was another really bad H (in GA and far N FL)

NorthHillsWx · August 21

1 hour ago, GaWx said:

- I believe that Oct is the most dangerous month for a direct landfall on the Gulf coast of FL.

Hurricane Michael confirms…

Seminole · August 21

2 hours ago, NorthHillsWx said:

Hurricane Michael confirms…

Since 1950 there have been 19 landfalling hurricanes that hit the United States in October. Ten in Florida and six in Louisiana. That is roughly one every 4 years long term average. Some recent notables since 2016, include Matthew, Nate, Michael, Delta and Zeta. The past decade the frequency has increased with one every 2 years.

CheeselandSkies · August 21

Atlantic tropics watchers in August 2024:

Believe I posted this for August, 2022 as well.

WxWatcher007 · August 21

Here it is--my peak season forecast. Enjoy.

21 minutes ago, WxWatcher007 said:

WxWatcher007 2024 Atlantic Peak Season Forecast

One year ago today, we had an extraordinarily active basin that set the stage for a high end peak season, with three named storms and two additional areas with high odds of development. This year, despite favorable conditions, generally we have the opposite, with models even struggling to latch onto an area with high odds of development through the end of the month.

Peak season has arrived however, which I define as August 20th through October 20th. During this ~8 week period approximately 2/3 of the Atlantic Hurricane season takes place historically.

This is my sixth annual peak season forecast, and despite the lack of activity, I think we're headed for an even bigger peak than last season which featured 15 named storms (NS), 6 hurricanes (H), and 3 major hurricanes (MH).

Last year was my best forecast. Let's keep the streak of good forecasts going.

I've been quite good overall other than a disastrous 2021

Seasonal Grades

2019 Grade: B+
2020 Grade: A-
2021 Grade: C
2022 Grade: B
2023 Grade: A

We've gotten accustomed to high NS years. In the recent past, we have seen seasons that feature hot starts in terms of NS, but climo has dictated that many of those systems were early season slop. I think our familiarity with that has given many of us a warped sense of the type of season it has been. To date, it has been historically active.

So far, we've seen 3 hurricanes, one of which was historic in Beryl as our earliest category 5 on record. Our ACE to date is 55.1 where climatology says it should be 20. Currently the North Atlantic is beating the WPAC in ACE, which averages 108.5 at this point. Relative to normal, our basin has been active compared to all the other northern hemisphere basins, which are having down years. I don't do the data analysis nearly as well as @GaWx, but this season to date is second in ACE in the satellite era (1966). It is only surpassed by the anomaly of anomalies, 2005.

Image below from the tremendous data tracking site by Dr. Kim Wood.

The image above says a lot. It says that we've been historically active and that it has been a quality over quantity season, much like 2017. It says that we have have ebbs and flows in the season, driven early on by Beryl but then carried further by Debby and Ernesto. Most important for this forecast, it says we're at a crossroad in the season.

Usually, the number of storms to date doesn't speak to the kind of peak we will have. I think that's the case here. I'm not sure we've had enough NS however to prevent the big NS forecasts from overshooting the mark, including my original seasonal forecast of 28 NS. That said, I think the type of storms we've seen so far does speak to the quality of storms we're likely to see during the peak, and that spells trouble.

Even at a middling pace the rest of the season, we're squarely on track for a hyperactive season.

So, what does the August 20 - October 20 period hold?
When the lid comes off, I expect a hyperactive peak.

Peak Season Forecast (Aug 20-Oct 20)
Named Storms: 15
Hurricanes: 10
Major Hurricanes: 5

I can't do the calculations but I imagine this kind of peak would put us well over 200 ACE, and I think we finish the season within the top 5 for ACE (227.2+) all time in the basin. This is a risky call when the next ten days look quiet on the models.

As a reminder, a typical season is 14/7/3.

Let's look at the factors that drive this forecast, and that requires looking beyond the 10 day deterministic models.

1. ENSO
The La Nina that was expected to be in place by now has been delayed, but probably won't be denied. Either way, having a cool neutral season thus far hasn't forced an unexpected wrinkle in the general atmospheric conditions over the basin.

Within this current regime, we have seen very low shear across the Caribbean, and nothing suggests that this will unexpectedly reverse through the peak of the season. If you're looking for how we don't have an active peak, even if my forecast is off, ENSO won't be the reason.

2. West African Monsoon
This has been interesting. Although it may not feel like it, one of the sub-themes of the season to me has been the number of vigorous African waves that have rolled off the continent during periods of activity. All three of our eventual hurricanes originated from those waves.

However, an active WAM can be a double edged sword. As we've seen in the last month or so, a lot of those waves have come off and brought big intrusions of SAL during the climatological peak of SAL season, or, as is the case in the past few weeks, come off too far north, being killed by both dry air and far cooler sea surface temperatures. The WAM is likely to stay active, but I think the climatological drop off in SAL coupled with waves beginning to come off the African continent at a lower latitude as the monsoon trough sags south should put future waves in better position to develop.

3. Wind Shear
As I noted above, wind shear has not been a major issue thus far this season. Keep in mind that yes, there's almost always wind shear around, but as we saw with Beryl, there have been stretches of anomalously low shear, particularly in the Caribbean. The biggest issue has been near the African coast this month, which may also contribute to the explanation of why we haven't seen a super active month considering the other factors. Keep in mind however that we've had two hurricanes in August.

Wind shear is driven largely by ENSO, which does not look to be getting hostile during the peak.

As we close August, the MDR is open for business on the shear side, and I think it's only going to get more favorable as we move into mid-September through October with a cool neutral or Nina ENSO state. What shear is present near the CONUS will be a factor of what troughing is around during that time, so I wouldn't read too much into exact figures. It's about the overall theme.

Importantly, I don't see any major issues either with anticyclonic wave breaking or TUTTs getting in the way of TC genesis this fall, which I think opens the tarmac for long runways for developing tropical cyclones to intensify into hurricanes and major hurricanes.

This increases my confidence that this remains a quality over quantity type season, though we will certainly have short lived NS and hurricanes that fail to get to major status.

4. SSTs/OHC
Not much needs to be said here. It's historically warm. Again. Unlike last year which needed to fight some hostile atmospheric conditions from the ENSO state, this year the atmospheric conditions (shear) should only help promote genesis, development, and intensification across the basin.

Folks often look to SSTs and Oceanic Heat Content to quickly determine whether a season is active or not, but much more goes into it. What I see from the current layout of SST anomalies, as well as the scale and geographical extent of OHC, is that there is highest end potential across much of the basin if in situ shear and dry air are kept in check. I said it a few months ago, but Beryl was the canary in the coal mine, and I think was a truly meaningful test case for what was possible if the much talked about conditions for a hyperactive season converged.

Parts of the basin may be running behind 2023 in terms of anomalies, but the anomalies this year are historic in their own right and critically, 2024 has much more favorable atmospheric conditions on balance.

5. MJO/CCKW
Not much time will be spent on this, but we know that the timing of the MJO and CCKWs matter in lighting up the basin. Right now with a favorable MJO you'd expect the Atlantic to be active, but the EPAC is. Until that basin quiets down in about a week, we're only likely to see homebrew potential rather than a large scale change over the MDR.

While these images may look more hostile in the Atlantic, I like seeing rising motion over the Indian Ocean as a signal for robust African wave activity. Climo should be able to overcome a "poorly timed" MJO.

6. SAL/Stability
I saved this for last, and if you are still reading at this point it's because while all of the other major large scale factors seem to be in alignment for a hyperactive peak, SAL and stability issues have been a big fly in the soup.

A few weeks ago, I posted in a thread that I thought the SAL would drop significantly in early August. It did happen to drop below the climatological norm, but rebounded in a big way after waves started moving off Africa much further north than we normally see.

July saw historic outbreaks of SAL which was a reversal from a year ago. Now, while SAL is lower than its been, the seven day average (image courtesy of Michael Lowry), is on the upward bound of climatology.

Dry air and stability issues are the primary culprit in us not seeing a higher amount of named storms IMO. Even with the three hurricanes we had, Beryl struggled to rapidly intensify near the Texas coast due to dry air entrainment, the same happened with Debby, and Ernesto had a shot to become a major hurricane but took too much time mixing out dry air north of the Antilles as it approached Bermuda.

That's the only thing that kept them in check. With shear imparting the dry air, all three hurricanes were in near pristine conditions for rapid intensification. That speaks to how critical a factor dry air has been this season imo.

I do think climatology will prevail in September and especially October when SAL and stability across the basin reach their nadir, but for a forecast of a hyperactive peak, this is the thing I'm watching closest. I will say, looking at the corridor of greater moisture along the traditional MDR path for CV waves and systems, I do think that once we start seeing waves come off Africa at a lower latitude, they will be able to develop much like Ernesto did.

What the SAL also tells me is that the further west you go, the more likely a wave is to find favorable conditions. As I've already laid out, the Caribbean is ripe for activity with well below normal wind shear. It is also more unstable, further away from the influence of SAL intrusions over the eastern tropical Atlantic.

https://tropic.ssec.wisc.edu/real-time/sal/g16split/movies/goes16split.html

These issues with stability aren't new in the basin. Dry air and stability have been a multi-year issue in suppressing activity in the eastern MDR. That history shows us that it hasn't had much of an impact during the peak of the season, and I expect that to be the case again. The western Atlantic will be the hotbed of above average activity even if SAL is above the climatological norm in early September.

Overall
I am making a bold call in forecasting a hyperactive peak, but I am choosing to look beyond the current surface depictions of the models and analyze the basin environment. It's about as favorable as it gets.

I think that virtually all factors point to at least an above average peak between August 20 - October 20. Perhaps the SAL and MJO need to better align to get the lid removed from the basin, but I do expect the switch to flip and bring with it plenty of high end activity. My expectation is that with continued favorable conditions in the Caribbean and western Atlantic relative to the eastern MDR, that we see vigorous waves gradually develop in this region, with more eastern MDR activity once the sharp climatological decline of SAL takes hold in September.

Unlike recent years, I think once the lid is off we're running all the way through the peak with very few breaks. This is the kind of year where late October and November could produce significant activity, so even if I am short on my H/MH projection those will still be possible through mid-November, especially in the Caribbean where OHC will be able to support it. I think the SAL and general dry air/stability in the basin suppresses NS activity early, but becomes less of a factor in September. That delay may be enough however to foreclose the high NS seasonal projections.

Final Note: Landfall Odds
The most impressive thing about this season so far is not that Beryl formed IMO, but that every system so far has made a landfall. Even Ernesto managed to directly impact Bermuda. Some of that is luck to be sure, but two hurricane landfalls on the CONUS before August 15 speaks to the broader steering pattern we've seen in the Atlantic, and weaker eastern MDR waves being able to skirt under breaks in the subtropical ridge and then developing when it's too late to escape. Fortunately for the US, Ernesto bucked this trend some and developed fast enough to be steered north by a trough.

Statistically, the more active the basin is, the higher the odds of a landfall. The Gulf has been a hot spot for activity to say the least in recent years, and with my expectation that the Caribbean will be exceptionally active, I don't think it's going out on a limb in saying that there will be additional hurricane landfalls in the CONUS.

To be clear, projecting landfalls at this range is more speculation than science, but I do believe the ongoing streak of major hurricane strikes on the US continues this season, and I think two major hurricanes will make landfall during this peak season forecast period. I do think that there will be at least one bona fide major hurricane threat to the U.S. East Coast as well, saying nothing of whether that's an actual hit or not, or what region of the coast. The last major EC strike was in 2004.

Once the lid comes off, I expect it to be full throttle.