2024 Global Model Runs Discussion (Out thru day 16)

[Woofde]

Regardless of what happens and we all know activity will resume in early September if not end August, it is certainly extremely unusual to see deterministic models this quiet post Aug. 20 in a record warm +AMO during a transitioning Nino year and if anyone is claiming that it was expected, that argument is certainly not in good faith because anyone who has been tracking the NATL for few years would know, the switch flip always happens around this time in NATL climo.

I still fully expect activity to resume in a couple of weeks and the hyperactivity threshold is still extremely easy to beat (we only need ~105ACE more, the average activity post Aug 20 in 1991-2020 climo is ~110 ACE) but this little lull is going to make it difficult for those near record breaking 220+ ACE numbers. We could still potentially get there if September peaks as it does and we get an extended CV season in October but its going to be difficult imo.

While I don't think anyone was expecting what we're seeing... Here's some food for thought.

In earlier years, global models (especially GFS and, for a while, CMC) were notorious for spinning up phantom storms that didn't materialize or vastly underperformed in reality. It was not uncommon during late August: it happened in 2017 when models made Harvey and PTC 10 MDR majors, it happened in 2022 when they showed numerous MDR storms before Danielle and Earl that poofed one by one, and I'm sure there were other years.

(In fact, phantoms can still happen even later, well into peak season. 2021 had one such episode that resulted in people season cancelling while Larry was still a Cat 3.)

My point is: Suppose we take it as a given that no other storms form in August (which is not a guarantee). Would it fundamentally change things if operational global models were showing storms that end up being phantoms, compared to the status quo of not showing anything at all?

Personally, I feel the answer should theoretically be no -- what models are showing 10 days in advance has no effect on the conditions that actually materialize 10 days later. Yet, I can't help but feel that the discussion here would be very different if the phantom storms appeared, even if we end up being fooled.

I agree with the sentiment in your post but here's the thing about it. Models would show phantom majors around Aug 20th because the conditions they saw were very favorable in the 10 days ahead as soon as the switch flipped. They are in the end numerical models without a mind of their own or any kind of reference to past seasons, they run off what they see every single run so the question then is, why aren't they seeing the favorable conditions yet this year and what is causing the delay? The current theory seems to be the high latitude waves combined with a heavy SAL season and a MJO stuck in phases 2/3 producing heavy easterly shear but all of this should be starting to decrease soon. The delay however will affect the activity of the season though as the NATL is using up peak season time. Like I said earlier, hyperactive season is still easy to beat but the more peak season time the NATL wastes, the less likely it is for those 220+ ACE numbers to verify. This of course does not say anything about the impact the season will have which has already been pretty significant.

Even the most active seasons have dead periods. The endless 2020 season had a dead period in peak season from late September to October. IIRC during that period it was very similar to this where models showed absolutely nothing. Many here were stating that the dead models were proof of an inactive back half and a season that was gonna bust. We all saw how that ended.

No one expected this inactive period, but its not a harbinger of a dead season like some are claiming. The global models are generally very blind to large pattern shifts. If they're still dead in a week from now, then that's a sign of something more than just intraseasonal variability.

[Category5Kaiju]

Something else that's important to consider: we've seen a lot of prominent Atlantic hurricanes form on short notice. Dorian and Fiona are two of the biggest examples. Dorian had practically no model support before it developed, but went on to become one of the strongest hurricanes in the basin on record by wind speed. Fiona also had very little model support in 2022, and there was speculation the Atlantic would have one of the least active seasons on record before it formed. A lot can change in this basin very quickly. It's easy to look at the operational models and assume the Atlantic will stay dead for the next two weeks, but I really don't believe that is a likely outcome. Once the AEJ weakens just a little, I think the MDR will come to life with significant activity. I don't think it will take until the middle of September to get another storm, in early September at the latest I think we'll see a substantial uptick.

I remember Dorian quite well. People thinking, even right around bell ringing date, that August may go nameless and be a dud. And then merely several weeks later, a monster packing 185 mph winds is approaching the Bahamas.

[skyline385]

While I don't think anyone was expecting what we're seeing... Here's some food for thought.

In earlier years, global models (especially GFS and, for a while, CMC) were notorious for spinning up phantom storms that didn't materialize or vastly underperformed in reality. It was not uncommon during late August: it happened in 2017 when models made Harvey and PTC 10 MDR majors, it happened in 2022 when they showed numerous MDR storms before Danielle and Earl that poofed one by one, and I'm sure there were other years.

(In fact, phantoms can still happen even later, well into peak season. 2021 had one such episode that resulted in people season cancelling while Larry was still a Cat 3.)

My point is: Suppose we take it as a given that no other storms form in August (which is not a guarantee). Would it fundamentally change things if operational global models were showing storms that end up being phantoms, compared to the status quo of not showing anything at all?

Personally, I feel the answer should theoretically be no -- what models are showing 10 days in advance has no effect on the conditions that actually materialize 10 days later. Yet, I can't help but feel that the discussion here would be very different if the phantom storms appeared, even if we end up being fooled.

I agree with the sentiment in your post but here's the thing about it. Models would show phantom majors around Aug 20th because the conditions they saw were very favorable in the 10 days ahead as soon as the switch flipped. They are in the end numerical models without a mind of their own or any kind of reference to past seasons, they run off what they see every single run so the question then is, why aren't they seeing the favorable conditions yet this year and what is causing the delay? The current theory seems to be the high latitude waves combined with a heavy SAL season and a MJO stuck in phases 2/3 producing heavy easterly shear but all of this should be starting to decrease soon. The delay however will affect the activity of the season though as the NATL is using up peak season time. Like I said earlier, hyperactive season is still easy to beat but the more peak season time the NATL wastes, the less likely it is for those 220+ ACE numbers to verify. This of course does not say anything about the impact the season will have which has already been pretty significant.

Even the most active seasons have dead periods. The endless 2020 season had a dead period in peak season from late September to October. IIRC during that period it was very similar to this where models showed absolutely nothing. Many here were stating that the dead models were proof of an inactive back half and a season that was gonna bust. We all saw how that ended.

No one expected this inactive period, but its not a harbinger of a dead season like some are claiming. The global models are generally very blind to large pattern shifts. If they're still dead in a week from now, then that's a sign of something more than just intraseasonal variability.

I think you need to read my comment again because you are making some extreme and completely incorrect assumptions from it, nowhere did I say anything about active seasons not having breaks or that a bust is on the horizon. I have said twice already in this page alone that a hyperactive season is very easy and still the likely outcome, all the current lull affects is the peak ACE number at the end of the season (in regards to the 220+ forecasts) which nobody can deny as we are wasting peak season days.

[Woofde]

I agree with the sentiment in your post but here's the thing about it. Models would show phantom majors around Aug 20th because the conditions they saw were very favorable in the 10 days ahead as soon as the switch flipped. They are in the end numerical models without a mind of their own or any kind of reference to past seasons, they run off what they see every single run so the question then is, why aren't they seeing the favorable conditions yet this year and what is causing the delay? The current theory seems to be the high latitude waves combined with a heavy SAL season and a MJO stuck in phases 2/3 producing heavy easterly shear but all of this should be starting to decrease soon. The delay however will affect the activity of the season though as the NATL is using up peak season time. Like I said earlier, hyperactive season is still easy to beat but the more peak season time the NATL wastes, the less likely it is for those 220+ ACE numbers to verify. This of course does not say anything about the impact the season will have which has already been pretty significant.

Even the most active seasons have dead periods. The endless 2020 season had a dead period in peak season from late September to October. IIRC during that period it was very similar to this where models showed absolutely nothing. Many here were stating that the dead models were proof of an inactive back half and a season that was gonna bust. We all saw how that ended.

No one expected this inactive period, but its not a harbinger of a dead season like some are claiming. The global models are generally very blind to large pattern shifts. If they're still dead in a week from now, then that's a sign of something more than just intraseasonal variability.

I think you need to read my comment again because you are making some extreme and completely incorrect assumptions from it, nowhere did I say anything about active seasons not having breaks or that a bust is on the horizon. I have said twice already in this page alone that a hyperactive season is very easy and still the likely outcome, all the current lull affects is the peak ACE number at the end of the season (in regards to the 220+ forecasts) which nobody can deny as we are wasting peak season days.

I was quoting you to add my own thoughts onto your post. I never said you thought that or made any of those assumptions. It definitely wasn't meant to be an argument man. I'm just passionate about the tropics thats all.

[TomballEd]

That gulf disturbance may need to be watched a little more closely eary next week, the 12z CMC now closes off a weak low, prior runs were an open wave, very interesting

Maybe a hint the wave CMC develops on the GFS. I see a single GEPS member similar to the op. It is a week away, so worth watching, But I suspect nothing happens.

I think the quick developing and poorly forecast warm ENSO doomed Dr. Gray's seasonal forecast. I was already nerding on the weather then, I was based in Lafayette and going offshore from various ports like Fourchon, Cocodrie, Venice, etc. I remember Rob Perillo the night the big MCS with a lot of lightning passed through LFT predicted it could develop. Became the D storm when I was on a land job in an alligator infested swamp just outside Cameron. I did a job a few weeks later out of Venice, on an ADTI run rig did not let the rig hands move their cars from the Shell helipad, all were destroyed. There was some damage driving to Venice. Danny was the big storm of the year, a Cat 1, and the CSU busted hard.

This bust probably won't be as big, and above normal ACE, because of Beryl, is still possible.

[Teban54]

To be clear, I don't care about ACE, I'm looking at the number of storms. To reach 25 named storms we'd need to have 20 develop in September and October. That's highly unlikely. We are on track for 18 or fewer named storms, assuming we do reach a very active period the last three weeks of September. To have no disturbances and no likely development over the coming week this late into August is very rare. The environment across the tropics is clearly not very favorable for development. I suspect that will change by the second week of September as we move into the last half of the season (typically, numbers-wise). For now, I'm enjoying the quiet time and planning on taking another comp day this Friday and next Friday going into the Labor Day weekend. I think I have had only a single Labor Day weekend off since I started in 1980. That would be quite a treat.

agreed and well said!

Especially the part about nothing happening this time of year being rare. I’d say that it is exceptionally rare to be occurring during what has been unanimously predicted to be a very very busy season.

To all people expecting active seasons to be more front-loaded or have a more active "early peak season" period -- read the chart below. It was made on August 9, but the point still stands.

Regardless of whether your ACE is above average, below average or normal, on average, each group of seasons distribute their ACE temporally in the exact same fashion. There's no reason to expect above-average seasons to be more front-loaded. If anything, they may be a little bit more back-loaded than below-average seasons are on September 1! (Above-average seasons have 30% of their ACE generated on September 1 on average, while below-average seasons have around 36%.)

 https://x.com/catinsight/status/1821866267810070791



Also, for those who are doubting the named storm forecasts, consider this: Compared to all years with >=19 named storms (2020, 2005, 2021, 1933, 2023, 1887, 1995, 2010, 2011, 2012), 2024 would still be ahead of all but two of the years ACE-wise until September 1, even if nothing forms before then. Yes, this list includes many years with weak and short-lived storms, but it also includes years with prolific ACE like 1995.

(Of course, you can say that you expect the remaining activity to be quality over quantity, but in that case it would be hard to argue that the ACE forecasts would bust.)

 https://x.com/catinsight/status/1825570498924937350

[MarioProtVI]

Something also worth noting: the 00z CFS has a significant hurricane in the MDR early September that I’m also pretty sure is what the ensembles are smelling. Forms around the 31st and practically takes a Lee-like track and probably even intensity wise - it gets down to sub-990 on the CFS’s res, which in reality translates to I believe sub-950. So at least there’s some backup, not plentiful, but shows the ensembles are picking it up as well.

[SFLcane]

That gulf disturbance may need to be watched a little more closely eary next week, the 12z CMC now closes off a weak low, prior runs were an open wave, very interesting

Maybe a hint the wave CMC develops on the GFS. I see a single GEPS member similar to the op. It is a week away, so worth watching, But I suspect nothing happens.

I think the quick developing and poorly forecast warm ENSO doomed Dr. Gray's seasonal forecast. I was already nerding on the weather then, I was based in Lafayette and going offshore from various ports like Fourchon, Cocodrie, Venice, etc. I remember Rob Perillo the night the big MCS with a lot of lightning passed through LFT predicted it could develop. Became the D storm when I was on a land job in an alligator infested swamp just outside Cameron. I did a job a few weeks later out of Venice, on an ADTI run rig did not let the rig hands move their cars from the Shell helipad, all were destroyed. There was some damage driving to Venice. Danny was the big storm of the year, a Cat 1, and the CSU busted hard.

This bust probably won't be as big, and above normal ACE, because of Beryl, is still possible.

Bust, doomed.. huh? Just a tad early for those words lol with 70-80% of season left. With la nina intensifying into the fall i would not be surprised if we are tracking way into nov in the caribbean. Not really anything extraordinary to not see hurricanes after 8/20 its not some kinda magic number were 5 tcs form overnight there has been plenty of late starting seasons that when on to be very busy if i can call it that since we have already had 3 hurricanes. Same song every year at this time only to have 2-3 hurricane spinning on 9/13.


Climatology plus MJO moving to the Maritime Continent should clear up these hurdles by early September.

[Hammy]

That gulf disturbance may need to be watched a little more closely eary next week, the 12z CMC now closes off a weak low, prior runs were an open wave, very interesting

Maybe a hint the wave CMC develops on the GFS. I see a single GEPS member similar to the op. It is a week away, so worth watching, But I suspect nothing happens.

I think the quick developing and poorly forecast warm ENSO doomed Dr. Gray's seasonal forecast. I was already nerding on the weather then, I was based in Lafayette and going offshore from various ports like Fourchon, Cocodrie, Venice, etc. I remember Rob Perillo the night the big MCS with a lot of lightning passed through LFT predicted it could develop. Became the D storm when I was on a land job in an alligator infested swamp just outside Cameron. I did a job a few weeks later out of Venice, on an ADTI run rig did not let the rig hands move their cars from the Shell helipad, all were destroyed. There was some damage driving to Venice. Danny was the big storm of the year, a Cat 1, and the CSU busted hard.

This bust probably won't be as big, and above normal ACE, because of Beryl, is still possible.

You do realize 1997 was one of the strongest El Nino years on record, right? It shouldn't even be mentioned in the same conversation as this year.

[BIFF_THE_UNRULY]

Lot of factors in play here. I've heard everything thrown out at there, SST's, Shear, all that stuff.

None of it really matters, the Sun itself pretty much determines the type of hurricane season we get and, In all honesty, it's not very hot this summer nor is it all that humid nor is the sun very active at the moment.

I know alot of people like to think Hurricanes are an Atmospheric thing, And they are somewhat but their creation or why they spawn really occurs because of optimal solar conditions that are somewhat not 100% understood.

[Weathertracker96]

Lot of factors in play here. I've heard everything thrown out at there, SST's, Shear, all that stuff.

None of it really matters, the Sun itself pretty much determines the type of hurricane season we get and, In all honesty, it's not very hot this summer nor is it all that humid nor is the sun very active at the moment.

I know alot of people like to think Hurricanes are an Atmospheric thing, And they are somewhat but their creation or why they spawn really occurs because of optimal solar conditions that are somewhat not 100% understood.

I’d love to live where you are because where I am, it has been HOT this summer.

But anyways, can anyone tell me how long does it take for operational to catch up to ensembles? I saw earlier ensembles still show activity. I see some are alluding the season is over but we can’t discount the Atlantic if ensembles are still showing things.

[sasha_B]

Lot of factors in play here. I've heard everything thrown out at there, SST's, Shear, all that stuff.

None of it really matters, the Sun itself pretty much determines the type of hurricane season we get and, In all honesty, it's not very hot this summer nor is it all that humid nor is the sun very active at the moment.

I know alot of people like to think Hurricanes are an Atmospheric thing, And they are somewhat but their creation or why they spawn really occurs because of optimal solar conditions that are somewhat not 100% understood.

"SSTs, shear, [etc.] don't really matter" is kind of a big claim. I'm not familiar with any mainstream source that holds that solar conditions are more of a factor than atmospheric conditions when it comes to tropical cyclogenesis - feel free to correct me if I'm just out of the loop on this, but I don't recall seeing meteorologists talk about solar 'weather' very much when it comes to tropical forecasting. I was also under the impression that (globally, at least) it has been rather hot this summer.

[TomballEd]

That gulf disturbance may need to be watched a little more closely eary next week, the 12z CMC now closes off a weak low, prior runs were an open wave, very interesting

Maybe a hint the wave CMC develops on the GFS. I see a single GEPS member similar to the op. It is a week away, so worth watching, But I suspect nothing happens.

I think the quick developing and poorly forecast warm ENSO doomed Dr. Gray's seasonal forecast. I was already nerding on the weather then, I was based in Lafayette and going offshore from various ports like Fourchon, Cocodrie, Venice, etc. I remember Rob Perillo the night the big MCS with a lot of lightning passed through LFT predicted it could develop. Became the D storm when I was on a land job in an alligator infested swamp just outside Cameron. I did a job a few weeks later out of Venice, on an ADTI run rig did not let the rig hands move their cars from the Shell helipad, all were destroyed. There was some damage driving to Venice. Danny was the big storm of the year, a Cat 1, and the CSU busted hard.

This bust probably won't be as big, and above normal ACE, because of Beryl, is still possible.

Bust, doomed.. huh? Just a tad early for those words lol with 70-80% of season left. With la nina intensifying into the fall i would not be surprised if we are tracking way into nov in the caribbean. Not really anything extraordinary to not see hurricanes after 8/20 its not some kinda magic number were 5 tcs form overnight there has been plenty of late starting seasons that when on to be very busy if i can call it that since we have already had 3 hurricanes. Same song every year at this time only to have 2-3 hurricane spinning on 9/13.


Climatology plus MJO moving to the Maritime Continent should clear up these hurdles by early September.

1997 was an El Nino, who knows what is suppressing the tropics completely now and for the next 7- 10 days. How do you know that will change? September climatology did nothing for 1997, why are you so sure it will do anything this year. BTW, I also said above normal ACE is quite possible because of all the Beryl ACE. You seem to enjoy reading my answers intentionally wrong because I'm saying some things you don't want to hear. I like tracking storms as much as the next guy. I hope you are right and we get 2 or 3 named storms a week in September. I really do. But I am starting to doubt it. It is no longer one run of the ensembles, it has been several in a row where the signal for a system beyond 10 days is fading after looking good a couple of days ago. You can keep pointing out the one member of 50 that menaces your favorite city if you want.
Just a weather forum.

[Weathertracker96]

Maybe a hint the wave CMC develops on the GFS. I see a single GEPS member similar to the op. It is a week away, so worth watching, But I suspect nothing happens.

I think the quick developing and poorly forecast warm ENSO doomed Dr. Gray's seasonal forecast. I was already nerding on the weather then, I was based in Lafayette and going offshore from various ports like Fourchon, Cocodrie, Venice, etc. I remember Rob Perillo the night the big MCS with a lot of lightning passed through LFT predicted it could develop. Became the D storm when I was on a land job in an alligator infested swamp just outside Cameron. I did a job a few weeks later out of Venice, on an ADTI run rig did not let the rig hands move their cars from the Shell helipad, all were destroyed. There was some damage driving to Venice. Danny was the big storm of the year, a Cat 1, and the CSU busted hard.

This bust probably won't be as big, and above normal ACE, because of Beryl, is still possible.

Bust, doomed.. huh? Just a tad early for those words lol with 70-80% of season left. With la nina intensifying into the fall i would not be surprised if we are tracking way into nov in the caribbean. Not really anything extraordinary to not see hurricanes after 8/20 its not some kinda magic number were 5 tcs form overnight there has been plenty of late starting seasons that when on to be very busy if i can call it that since we have already had 3 hurricanes. Same song every year at this time only to have 2-3 hurricane spinning on 9/13.


Climatology plus MJO moving to the Maritime Continent should clear up these hurdles by early September.

1997 was an El Nino, who knows what is suppressing the tropics completely now and for the next 7- 10 days. How do you know that will change? September climatology did nothing for 1997, why are you so sure it will do anything this year. BTW, I also said above normal ACE is quite possible because of all the Beryl ACE. You seem to enjoy reading my answers intentionally wrong because I'm saying some things you don't want to hear. I like tracking storms as much as the next guy. I hope you are right and we get 2 or 3 named storms a week in September. I really do. But I am starting to doubt it. It is no longer one run of the ensembles, it has been several in a row where the signal for a system beyond 10 days is fading after looking good a couple of days ago. You can keep pointing out the one member of 50 that menaces your favorite city if you want.
Just a weather forum.

I don’t see anything wrong with what SFLcane posted. He’s right in that we have to continue watching the tropics. It’s also best to watch all ensembles since they show something. But hey, if you think the season is done than you have that right to think that. I & many others will not have that mindset. Hurricane season ends November 30th.
Should a hurricane threatened land moving forward, people shouldn’t have issues getting supplies since so many have canceled the season.

[Hammy]

Reminder: Models showed a storm-free August 2019 five days before Dorian formed.

 https://x.com/AndyHazelton/status/1826353695048827170

I wonder if the models are having difficultly because of the monsoon trough, if they're struggling to break any individual piece off of this, where they would have less trouble if we were having the more typical setup of separate, spaced-apart tropical waves. 2019 appears to have featured a similar setup (and amazing it failed to catch Chantal even 48 hours out)

[MarioProtVI]

Reminder: Models showed a storm-free August 2019 five days before Dorian formed.

 https://x.com/AndyHazelton/status/1826353695048827170

I wonder if the models are having difficultly because of the monsoon trough, if they're struggling to break any individual piece off of this, where they would have less trouble if we were having the more typical setup of separate, spaced-apart tropical waves. 2019 appears to have featured a similar setup (and amazing it failed to catch Chantal even 48 hours out)

Beginning to think this too. Last year also had this issue with modeling showing almost nothing (around the time Andy made the “no storms and no hurricanes” tweet) the rest of August; in reality the models were struggling to catch onto the TC outbreak of Franklin to Katia (which happened a few days after he said that) because it had difficulty trying to resolve the monsoon trough.

[ConvergenceZone]

I can see where everyone is coming from. I think we should wait until Mid September. If activity still seems low at that time, then I think we will DEFINATELY be looking at a Bust.

[Category5Kaiju]

Bust, doomed.. huh? Just a tad early for those words lol with 70-80% of season left. With la nina intensifying into the fall i would not be surprised if we are tracking way into nov in the caribbean. Not really anything extraordinary to not see hurricanes after 8/20 its not some kinda magic number were 5 tcs form overnight there has been plenty of late starting seasons that when on to be very busy if i can call it that since we have already had 3 hurricanes. Same song every year at this time only to have 2-3 hurricane spinning on 9/13.


Climatology plus MJO moving to the Maritime Continent should clear up these hurdles by early September.

1997 was an El Nino, who knows what is suppressing the tropics completely now and for the next 7- 10 days. How do you know that will change? September climatology did nothing for 1997, why are you so sure it will do anything this year. BTW, I also said above normal ACE is quite possible because of all the Beryl ACE. You seem to enjoy reading my answers intentionally wrong because I'm saying some things you don't want to hear. I like tracking storms as much as the next guy. I hope you are right and we get 2 or 3 named storms a week in September. I really do. But I am starting to doubt it. It is no longer one run of the ensembles, it has been several in a row where the signal for a system beyond 10 days is fading after looking good a couple of days ago. You can keep pointing out the one member of 50 that menaces your favorite city if you want.
Just a weather forum.

I don’t see anything wrong with what SFLcane posted. He’s right in that we have to continue watching the tropics. It’s also best to watch all ensembles since they show something. But hey, if you think the season is done than you have that right to think that. I & many others will not have that mindset. Hurricane season ends November 30th.
Should a hurricane threatened land moving forward, people shouldn’t have issues getting supplies since so many have canceled the season.

Exactly. In fact, forget overall ACE for a sec. I strongly think that sometime in September or even October, we’re going to be tracking a potentially very impactful system. This season has been impactful enough, from Beryl to Debby. I see no reason why September and October would not be impactful in some way, unfortunately.

[Hammy]

It's worth pointing out that the CFS has been consistently showing the lid coming off between August 28 and September 2 and shows five storms (at least) developing in the MDR between August 28 and September 15, along with at least one (potentially two) storms in the Gulf of Mexico during that same time--it was also showing a very limited activity for August leading into it.

[Jr0d]

I am willing to bet that by Labor Day weekend(August 31st) that somewhere in the CONUS will be either in an orange potential development cone or in the cone of uncertainty from a classified system.

If I am wrong I will give Storm2k $10...if anyone takes me up on the bet and I am right, they will donate $10...

Any takers?