2024 Atlantic Hurricane Season

[JPWX]

Been a lot of speculation as to what has been the leading cause for the inactivity in the Atlantic from the African Monsoon being too far north and other interesting things. I am more inclined to believe it's the MJO. Here's why. Here's the 00z Euro Weeklies 200mb divergence/velocity potential anomaly. Green is rising air and brown is sinking air. Look at where these two Western Pacific systems are. They are in the upward motion sector in the Western Pacific! Since Ernesto dissipated, we've been in the unfavorable MJO phases of 4,5,and 6. MJO is currently forecasted to go into Phase 7. These unfavorable phases are favorable in the Pacific. Ernesto dissipated August 20th. Since then, the Eastern Pacific has featured Gilma, Hector, and Hone with the Western Pacific featuring Typhoon Shanshan, Typhoon Yagi, and now TD 13W. This has allowed the Pacific ACE to surpass the Atlantic even though both Eastern/Western Pacific are still well below normal. Now, you are going to get development in the Western Gulf from this Caribbean feature next week which interestingly enough puts us right at the week of peak season (September 10th). Why? Because you have upward motion in the Western Gulf as indicated on the Euro Weeklies plus you have a frontal system pushing in that will usher in cooler air. This creates convergence. You know colder air colliding with warm air creating rising motion which leads to thunderstorms. You may be asking Well, how can you get development in Phase 6 or 7? Simply put, you look close to home for development instead of the MDR. Looking ahead the MJO should shift back into the favorable phases of 8,1,2, and 3 towards the 25th onward. This is shown on the EWP (Empirical Wave Propagation) diagram. What we should see is an active and impactful late season.

This is me explaining the most logical reason as to why that you may not be hearing from others and implying not to let your guard down.

 

[Clancy]

Lots of places to watch, though all low-confidence for now.

 

[Clancy]

NHC now assigning a 40% chance for 7-day development on this disturbance over northern Belize.

3. Southwestern Gulf of Mexico:
A tropical wave located over Belize and the Yucatan Peninsula of
Mexico is producing disorganized showers and thunderstorms. The
wave is forecast to move into the Bay of Campeche on Saturday,
where it could then begin to interact with a frontal boundary. A
tropical depression could form during the early or middle part of
next week while the system moves slowly northwestward over the
southwestern Gulf of Mexico.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 7 days...medium...40 percent.

 

[jiharris0220]

Ok, so apparently over expansion of Hadley cell in the African/Indian oceanic region leads to hyper extension of the ITCZ and monsoon trough too far north in latitude.

Which then causes TWs to form above 15DgrN into Narnia.

But not only that, the hyper extension of the ITCZ leads to unfavorable surface wind interactions, so there’s not much in the way of convergence, so what would be a ITCZ is just now a ITZ pretty much.

This unfavorable orientation of the ITCZ causes poor fluid trapping, leading to very poor moisture pocketing in TWs which leaves them far more vulnerable to dry air intrusions than what would be normal this time of year.

Throw in far above average 200mb tropospheric temperatures, (the highest on record in the North Atlantic I believe. Anthropogenic GW related?) you’ve now created severe barotropic stability, which the Climate Euro model actually verified in predicting ironically enough.

So even the TWs that manage to make it far enough south simply end up playing “how anemic can I get before I go to hell”

And now that we’re in the sinking phase of the MJO, wind shear has now come into play and pretty much put the nail in the coffin for this season.

We will probably have to wait until mid October for the next window of MJO favorability, as the monsoon trough will by then sink far enough south in the ITCZ having better orientation to roll up TWs.

This coinciding with the annual cooling of the troposphere with still above average SST should finally spark up the season again.

Although we would need a miracle (or not miracle depending on how you look at it) for the record breaking ace numbers to verify.

As in, the most active October/November on record type of activity, or we could very well have seen our last storm with Ernesto.

 

[JPWX]

I'll just leave this here.

 

[jiharris0220]

I'll just leave this here.

Any “experts” claiming it was hunga Tonga don’t know what they’re talking about.

As it was proven that the eruption despite its somewhat large size only cooled the planet by a less than negligible amount.

The sinking phase of the MJO is only now coming to play in delaying the Atlantic further, my explanation above could very well be wrong but based off of what I’ve looked at so far it’s the most likely.

So many unfavorable circumstances happening all at once would be ridiculous most of the time but obviously this season is a clear cut definition of a black swan event.

For such a hyperactive start only to dwindle to likely nothing forming in the heart of the season can’t be explained away with just the MJO.

Here’s the current set up of the monsoon trough, can’t say I’ve seen anything like it. It’s damn near Morocco, I can’t think of anything else that would cause this other than a hyper expanded Hadley cell due to well above average 200mb temperatures.

 

[Clancy]

40/60 as of this morning.

1. Southwestern Gulf of Mexico:
A tropical wave over the Bay of Campeche is producing disorganized
showers and thunderstorms. An area of low pressure is forecast to
develop while the wave interacts with a frontal boundary during
the next couple of days. Environmental conditions are forecast to
be conducive for development, and a tropical depression could form
during the early or middle part of next week while the system moves
slowly northwestward to northward over the southwestern Gulf of
Mexico.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...medium...60 percent.

 

[JPWX]

You do realize that we've been in Phases 4 and 5 (unfavorable for Atlantic development) since August 20th. Which corresponds well to all the activity in the Pacific. I'll keep my mouth shut on this topic any further, but if the Atlantic lights up late season, it's because we've gone back into the favorable phases of 8,1,2, and 3.

 

[jiharris0220]

You do realize that we've been in Phases 4 and 5 (unfavorable for Atlantic development) since August 20th. Which corresponds well to all the activity in the Pacific. I'll keep my mouth shut on this topic any further, but if the Atlantic lights up late season, it's because we've gone back into the favorable phases of 8,1,2, and 3.

“You do realize that we've been in Phases 4 and 5 (unfavorable for Atlantic development) since August 20th”

The thing is there is a time lag between the MJO and atmosphere favorability.

In the Antarctic region the lag response can be greater than 20 days.

For the Atlantic, favorability peaks after the passage of the MJO which the prime location for it would be the 3-4 region.

This is why I said the suppresive phase of the MJO is (just now) coming into play.

And again, let’s say the MJO was indeed causing unfavorable conditions since August, this alone would absolutely not explain the September shut down. Especially if you consider the fact 2017 (for one example) was right in the middle of the suppression phase of the MJO during peak season. https://ncics.org/pub/mjo/archive/2017/2017-09-26/v2/

Unless I’m made aware of other factors or am proven wrong I’m not sure we can just say, whoopsie! Wrong MJO timing.

And according to this recent research paper (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2023GL107701)
Solar cycles also play a role in MJO lag time responses. Seems like a reach on the surface but it makes sense considering OLR plays a big role in MJO intensity and synoptic scale enhancement (or suppression) of convection.

 

[Clancy]

GOM system is 50/70 now. Also watching an area in the middle of the Atlantic.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Sat Sep 7 2024

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Western Gulf of Mexico (AL91):
An area of low pressure has formed over the Bay of Campeche and is
producing disorganized showers and thunderstorms. The system is
forecast to drift slowly northward for a couple of days while it
interacts with a frontal boundary. Environmental conditions are
forecast to be conducive for development, and a tropical depression
is likely to form during the early or middle part of next week while
the system moves generally northward near or along the Mexican and
Texas Gulf coastline. Interests along the western Gulf of Mexico
coast should closely monitor the progress of this system.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 7 days...high...70 percent.

2. Central Tropical Atlantic:
An area of low pressure over the central tropical Atlantic is
producing disorganized showers and thunderstorms. Gradual
development of this system is possible while the system meanders
during the next couple of days, and a tropical depression could form
early next week. The system is then forecast to move
west-northwestward at about 10 mph across the central tropical
Atlantic during the middle to latter part of next week.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...medium...40 percent.

3. Eastern and Central Tropical Atlantic:
Disorganized showers and thunderstorms associated with a trough of
low pressure are located several hundred miles east-southeast of
the Cabo Verde Islands. Some slow development of this system is
possible as it interacts with a tropical wave expected to move off
the African continent early next week and moves west-northwestward
at 5 to 10 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.


Forecaster Bucci

 

[jiharris0220]

GOM system is 50/70 now. Also watching an area in the middle of the Atlantic.

View attachment 29768

Could become a hurricane looking at the gfs alone.

But if I’m being honest I’m questioning if we’ll see another hurricane before the 20th at this point.

 

[Clancy]

60/80 now. How much of it sticks over water will be worth watching, especially with some guidance having it scrape along NE Mexico. The Central Atlantic systems are now both at medium chances, though they're not much to worry about for now.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Sat Sep 7 2024

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Western Gulf of Mexico (AL91):
An area of low pressure located over the Bay of Campeche is
producing disorganized showers and thunderstorms. This disturbance
is forecast to drift slowly northward during the next several days
while it interacts with a frontal boundary. Environmental conditions
are forecast to become more conducive for development, and a
tropical depression is likely to form while the system moves
generally northward near or along the Gulf coast of Mexico and Texas
through the middle of next week. Interests along the western Gulf of
Mexico coast should closely monitor the progress of this system.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 7 days...high...80 percent.

2. Central Tropical Atlantic:
Shower and thunderstorm activity associated with an area of low
pressure over the central tropical Atlantic has begun to show signs
of organization. Gradual additional development is possible while
the system meanders over the central tropical Atlantic through
Monday and then moves generally westward at about 10 mph through the
rest of next week.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...medium...50 percent.

3. Eastern and Central Tropical Atlantic:
Disorganized showers and thunderstorms associated with a trough of
low pressure are located several hundred miles southwest of
the Cabo Verde Islands. The disturbance is expected to move very
little during the next few days until it potentially interacts with
a tropical wave that is forecast to move off the west coast of
Africa by early Monday. Environmental conditions are expected to be
favorable for gradual development of this system, and a tropical
depression could form by the middle or late portions of next week.
The system is expected to begin moving slowly westward by the end
of the week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...40 percent.


Forecaster D. Zelinsky

 

[JPWX]

I'm just hoping North MS gets some significant rainfall off this to make a dent in the drought. Haven't had one inch or more of rain since July 20th.

 

[Clancy]

70/80 at 2 AM.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sun Sep 8 2024

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Western Gulf of Mexico (AL91):
Recent satellite wind data indicate a broad area of low pressure is
located over the Bay of Campeche. The low is producing disorganized
showers and thunderstorms over the southwestern Gulf of Mexico while
interacting with a frontal boundary. This system is forecast to
drift slowly northwestward during the next couple of days, and
environmental conditions are expected to become more conducive for
development. A tropical depression is likely to form while the
system moves generally northward near or along the Gulf coast of
Mexico and Texas through the middle of the week. Interests along
the western Gulf Coast should closely monitor the progress of this
system.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...80 percent.

2. Central Tropical Atlantic (AL92):
Showers and thunderstorms associated with an elongated area of low
pressure over the central tropical Atlantic are showing gradual
signs of organization. Environmental conditions appear conducive for
additional development of this system, and a tropical depression
could form while the system meanders over the central tropical
Atlantic through Monday and then moves generally westward at about
10 mph through the rest of the week.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 7 days...medium...50 percent.

3. Eastern and Central Tropical Atlantic:
A trough of low pressure located several hundred miles southwest of
the Cabo Verde Islands is producing some disorganized showers and
thunderstorms. The disturbance is expected to move very little
during the next couple of days until it potentially interacts with
a tropical wave that is forecast to move off the west coast of
Africa by early Monday. Environmental conditions are expected to be
favorable for gradual development of this system, and a tropical
depression could form by the middle or latter part of the week while
the system moves slowly westward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...50 percent.


Forecaster Reinhart

 

[Clancy]

80/90. Convection is increasing and HH will be dispatched later today.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM CCA

Tropical Weather Outlook...Corrected
NWS National Hurricane Center Miami FL
800 AM EDT Sun Sep 8 2024

Corrected category for the 48 hour probability for AL92

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Western Gulf of Mexico (AL91):
Showers and thunderstorms have increased this morning in association
with a broad area of low pressure located over the southwestern Gulf
of Mexico. This system is forecast to drift slowly northwestward
during the next couple of days, and environmental conditions are
expected to become conducive for additional development. A tropical
depression is likely to form during the next couple of days as the
system moves generally northwestward and then northward near or
along the Gulf coast of Mexico and Texas through the middle of the
week. Interests along the western and northwestern Gulf Coast should
closely monitor the progress of this system. Watches could be
required for portions of the western Gulf coast later today or
tonight. An Air-Force Reserve Hurricane Hunter aircraft is also
scheduled to investigate the system later today.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

2. Central Tropical Atlantic (AL92):
Showers and thunderstorms associated with an elongated area of low
pressure over the central tropical Atlantic continue to show some
signs of organization. Environmental conditions appear conducive for
additional development of this system, and a tropical depression
could form while the system meanders over the central tropical
Atlantic through Monday and then begins to move generally westward
at around 10 mph through the rest of the week.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 7 days...medium...60 percent.

3. Eastern and Central Tropical Atlantic:
A trough of low pressure located several hundred miles southwest of
the Cabo Verde Islands is producing a broad area of disorganized
showers and thunderstorms. This system is expected to move very
little during the next couple of days until it potentially interacts
with a tropical wave that is forecast to move off the west coast of
Africa on Monday. Environmental conditions thereafter are expected
to be favorable for gradual development of this system, and a
tropical depression could form by the middle or latter part of the
week while the system begins moving slowly west-northwestward.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...50 percent.


Forecaster Papin

 

[wx_guy]

90/90 now, likely to be a storm or PTC at 5 PM in about an hour. HH are in the storm now.

 

[wx_guy]

In the blob on the left side of the system, the HH have found estimated surface-level winds (using SFMR) of about 55 mph and flight-level winds around 70 mph. I'd be very surprised if this wasn't already a tropical storm. Just gotta see if they find a closed center.

 

[TornadoFan]

NHC will be issuing advisories on the system in the Gulf.

 

[Clancy]

Advisory 1 for PTC 6 is out.

 

[GeneralChow]

I'm getting Western Pacific vibes.