Expert Forecasts for the 2024 NATL Hurricane Season

[Spacecoast]

I think the verification section will have to read something like this:
(My words, not Phil's)

Below-normal tropical cyclone activity occurred during the two-week period from
August 20–Sept 2. We had assigned an 20% probability of above-normal activity, with a 55%
chance of normal and a 25% chance of below-normal activity during the two-week period.


Parameter Definition Probability in Each Category
Above-Normal Upper Tercile (>22 ACE) 20%
Normal Middle Tercile (7–22 ACE) 55%
Below-Normal Lower Tercile (<7 ACE) 25%

Observed ACE = ~0

[Spacecoast]

.

[LarryWx]

https://tropical.colostate.edu/Forecast/2024-0903.pdf

COLORADO STATE UNIVERSITY FORECAST OF ATLANTIC HURRICANE ACTIVITY FROM SEPTEMBER 3–16, 2024
We believe that the most likely category for Atlantic hurricane activity in the next two weeks is below-normal (60%), with near-normal (30%) and above-normal (10%) being less likely.
(as of 3 September 2024)

[Teban54]

Emphasis mine:

While we still expect the 2024 Atlantic hurricane season to end up above average,

With the exception of the western Caribbean and southern Gulf of Mexico, largescale environmental conditions look relatively unfavorable for the next ~7 days but look to get more conducive for tropical cyclone activity towards the middle of September. Global model ensembles highlight the potential for a strong African easterly wave emerging off of the west African coast in 8–9 days. It is still too early to determine what this system’s future would be.

The ECMWF EPS ensemble (Figure 4) is highlighting a robust African easterly wave emerging off of Africa in 8–9 days. While current vertical wind shear is relatively high across the Atlantic, it is forecast to weaken substantially by mid-September (Figure 5). The GEFS ensemble is much weaker with any African easterly wave development towards the middle of September (Figure 6).

The MJO is forecast to propagate eastward across the western Pacific and into the Western Hemisphere over the next two weeks (Figure 7). These phases are typically relatively unfavorable for Atlantic hurricane activity, although vertical wind shear does look to become much more favorable towards the end of the two-week period.

While the season got off to a very fast start with three hurricanes by 14 August, the season has tailed off dramatically over the past couple of weeks. This lack of activity will be discussed in detail in a note on our website by the end of today (3 September).

[MarioProtVI]

https://tropical.colostate.edu/Forecast/2024-0903.pdf

COLORADO STATE UNIVERSITY FORECAST OF ATLANTIC HURRICANE ACTIVITY FROM SEPTEMBER 3–16, 2024
We believe that the most likely category for Atlantic hurricane activity in the next two weeks is below-normal (60%), with near-normal (30%) and above-normal (10%) being less likely.
(as of 3 September 2024)

At this rate we’re gonna to struggle to even get above 100, or even worst case 75. 2 weeks of essential peak time basically wasted and by the time we reach late September the MDR is already closing for business. I do not have much faith in the models for October, as they have been notoriously bad this year I would not rule out another 2021-style shutdown next month, given that, just like this year, they were constantly predicting an active October and all we got was a weak nor’easter-derived TS at the very end of the month. This might even end up worse then 2013’s bust, and I seriously worry for the future of CSU forecasting given that at the current rate, they’re going to lose a lot of funding with the botched forecasts.

[Spacecoast]

https://tropical.colostate.edu/Forecast/2024-0903.pdf

COLORADO STATE UNIVERSITY FORECAST OF ATLANTIC HURRICANE ACTIVITY FROM SEPTEMBER 3–16, 2024
We believe that the most likely category for Atlantic hurricane activity in the next two weeks is below-normal (60%), with near-normal (30%) and above-normal (10%) being less likely.
(as of 3 September 2024)

60% chance of less than 10 ACE, during peak of the season.....This would put the season @ less than 65.1 ACE by Sept 16th, which would be below the 71.9 ACE for an 'average' season.

"The only ACE generated during the two-week period was 1 ACE by Ernesto on August 20. "

I was thinking ~zero, but I guess Ernesto had some leftover juice.

[chaser1]

https://tropical.colostate.edu/Forecast/2024-0903.pdf

COLORADO STATE UNIVERSITY FORECAST OF ATLANTIC HURRICANE ACTIVITY FROM SEPTEMBER 3–16, 2024
We believe that the most likely category for Atlantic hurricane activity in the next two weeks is below-normal (60%), with near-normal (30%) and above-normal (10%) being less likely.
(as of 3 September 2024)

60% chance of less than 10 ACE, during peak of the season.....This would put the season @ less than 65.1 ACE by Sept 16th, which would be below the 71.9 ACE for an 'average' season.

"The only ACE generated during the two-week period was 1 ACE by Ernesto on August 20. "

I was thinking ~zero, but I guess Ernesto had some leftover juice.

Now THAT's what I call "an ace in the hole"

[Weathertracker96]

https://tropical.colostate.edu/Forecast/2024-0903.pdf

COLORADO STATE UNIVERSITY FORECAST OF ATLANTIC HURRICANE ACTIVITY FROM SEPTEMBER 3–16, 2024
We believe that the most likely category for Atlantic hurricane activity in the next two weeks is below-normal (60%), with near-normal (30%) and above-normal (10%) being less likely.
(as of 3 September 2024)

At this rate we’re gonna to struggle to even get above 100, or even worst case 75. 2 weeks of essential peak time basically wasted and by the time we reach late September the MDR is already closing for business. I do not have much faith in the models for October, as they have been notoriously bad this year I would not rule out another 2021-style shutdown next month, given that, just like this year, they were constantly predicting an active October and all we got was a weak nor’easter-derived TS at the very end of the month. This might even end up worse then 2013’s bust, and I seriously worry for the future of CSU forecasting given that at the current rate, they’re going to lose a lot of funding with the botched forecasts.

That’s my concern too. I’m also concerned that people won’t listen to them, NOAA and other weather forecasters anymore. I think the sensational words some Mets used to describe this year contributed to the hype. I’m really concerned that the credibility these agencies had might be gone in the future.

[tolakram]

I've had to clean up this thread 3 times now.

No politics of any kind is allowed on Storm2K. Period. If you think this is a bad idea go somewhere else, it's not negotiable. This is a weather enthusiast forum for discussing weather, which can be done without politics and CAN be done in a respectful fashion.

AND PLEASE, USE THE REPORT BUTTON! Makes my job easier. Thanks! We might not agree with every report, but that's ok.

[chaser1]

"This lack of activity will be discussed in detail in a note on our website by the end of today (3 September)".
Came home from work expecting to read this final write-up note that CSU referenced but was surprised to not see it here in this thread?

[blp]

This tells the story so far.

 https://x.com/burgwx/status/1830379848965013813

[supercane]

"This lack of activity will be discussed in detail in a note on our website by the end of today (3 September)".
Came home from work expecting to read this final write-up note that CSU referenced but was surprised to not see it here in this thread?

It's finally up.
 https://twitter.com/philklotzbach/status/1831185547861114940



Link at https://tropical.colostate.edu/Forecast/2024_0903_seasondiscussion.pdf
Copied from the executive summary/abstract:

1
DISCUSSION OF 2024 ATLANTIC HURRICANE SEASON TO DATE AND FORECAST THOUGHTS ON THE REST OF THE SEASON
The 2024 Atlantic hurricane season got off to an extremely fast start, with Hurricane Beryl becoming the earliest Category 5 hurricane in the Atlantic on record. Hurricanes Debby and Ernesto followed in early and mid-August, respectively, leading to a well above-average season through the middle part of August. However, since Ernesto dissipated on 20 August, the Atlantic has had no named storm activity. As we near the climatological peak of the Atlantic hurricane season, we discuss the 2024 season in detail, including several possible reasons for the recent dearth in Atlantic hurricane activity. These reasons include: 1) a northward-shifted monsoon trough resulting in African easterly waves emerging at too far north of a latitude, 2) extremely warm upper-level temperatures resulting in stabilization of the atmosphere, 3) too much easterly shear in the eastern Atlantic, and more recently 4) unfavorable subseasonal variability associated with the Madden-Julian oscillation. We believe that it is likely a combination of these factors (and perhaps others) that have led to this recent quiet period. We still do anticipate an above-normal season overall, however, given that large-scale conditions appear to become more favorable around the middle of September. We note that we are not issuing a new seasonal forecast with this discussion.

[cycloneye]

Great discussion from Phil. He still does not raise the white flag and expects activity in October and November.

[cycloneye]

JB down to 15-20 and ACE between 175-195.

 https://x.com/BigJoeBastardi/status/1831323344383398143




 https://x.com/BigJoeBastardi/status/1831328079312200184

[MGC]

Just read CSU latest discussion on the progress of or lack thereof of the 2024 hurricane season. Lots of excuses, kind of like having your 5 year old explain why he ate all the cookies. IMO they are going to BUST big time....we are talking epic bust. Really, they think end of September, October and November are now going to be hyper active? I have my doubts. While it is possible the odds are long IMO. I'm thinking maybe 12-14 named systems total this season. Lets just hope they are all fish and we don't see a deadly landfall......MGC

[tolakram]

Just read CSU latest discussion on the progress of or lack thereof of the 2024 hurricane season. Lots of excuses, kind of like having your 5 year old explain why he ate all the cookies. IMO they are going to BUST big time....we are talking epic bust. Really, they think end of September, October and November are now going to be hyper active? I have my doubts. While it is possible the odds are long IMO. I'm thinking maybe 12-14 named systems total this season. Lets just hope they are all fish and we don't see a deadly landfall......MGC

I think that's too harsh, especially since every agency is going to bust, but just my opinion. I note he explicitly stated they are not changing their forecast at this time. That might seem a bit off but scientifically they don't have any solid reasoning for a slow season, just guesses, so their forecast stands. It will be interesting to see if they buckle and lower even though there is no solid evidence that works with their hindcasting. If they do change then what does that say about their methodology? CSU is in the un envious position of having a theory they are testing.

[Bigtenfan]

I agree that it is too harsh criticism of the CSU people.

That said: This came up on another board. How did CSU become the be all to end all of seasonal hurricane forecasting as opposed to say the University of Miami which is a stone's throw from the NHC? To me that is like UM being the forecaster for snowy New England winters.

[Emmett_Brown]

The position and strength of the monsoon trough, the upper level temperatures of the tropopause and their affect on atmospheric stability (maybe a solar cycle component to this?), the "too much of a good thing" easterly shear in the eastern Atlantic, and the influence of MJO will all likely get more weight in future years long range hurricane forecasts. I'm thankful that they published their thoughts about how the season is going so that we can all learn. It takes guts for them to own when their forecasts don't go perfectly, so kudos to them.

It will be fascinating to watch how the remainder of this potentially explosive season unfolds.

[Emmett_Brown]

I agree that it is too harsh criticism of the CSU people.

That said: This came up on another board. How did CSU become the be all to end all of seasonal hurricane forecasting as opposed to say the University of Miami which is a stone's throw from the NHC? To me that is like UM being the forecaster for snowy New England winters.

There are over 25 agencies issuing seasonal hurricane forecasts now, so the forecast of any individual agency, (including CSU) will likely be less important in the future. The average of the agencies is probably going to be more important.

[Ubuntwo]

I agree that it is too harsh criticism of the CSU people.

That said: This came up on another board. How did CSU become the be all to end all of seasonal hurricane forecasting as opposed to say the University of Miami which is a stone's throw from the NHC? To me that is like UM being the forecaster for snowy New England winters.

Dr. William M. Gray I believe is the answer to your question.