2024 Atlantic Hurricane Season

[GaWx]

Regarding the potential TC or STC forming just off the SE coast by early next week, here are some 12Z model runs:

-GFS 1003 TS that landfalls near Wilmington, NC

-CMC/UKMET/ICON no TC/STC

-Euro: a very weak low (1011) that landfalls at GA/SC border

-JMA: low moves NE to 350 miles E of NC/VA border at 1003 (ST or T); then stalls and is forced back SW to 300 miles E of Hatteras while strengthening to 998 at 192

[WxWatcher007]

30 minutes ago, GaWx said:

Regarding the potential TC or STC forming just off the SE coast by early next week, here are some 12Z model runs:

-GFS 1003 TS that landfalls near Wilmington, NC

-CMC/UKMET/ICON no TC/STC

-Euro: a very weak low (1011) that landfalls at GA/SC border

-JMA: low moves NE to 350 miles E of NC/VA border at 1003 (ST or T); then stalls and is forced back SW to 300 miles E of Hatteras while strengthening to 998 at 192

Looks like the signal has faded substantially but the general environment looks conducive for some kind of genesis—tropical or baroclinic. 

[GaWx]

15 minutes ago, WxWatcher007 said:

Looks like the signal has faded substantially but the general environment looks conducive for some kind of genesis—tropical or baroclinic. 

These blocking types of patterns are notoriously difficult for the models to get a handle on, which is exhibited by the widely varying 12Z model solutions. This is what JB calls the “ridge over troubled water” pattern.

[StantonParkHoya]

31 minutes ago, GaWx said:

These blocking types of patterns are notoriously difficult for the models to get a handle on, which is exhibited by the widely varying 12Z model solutions. This is what JB calls the “ridge over troubled water” pattern.

From a sensible weather standpoint, it doesn’t really matter much, it’s generally the same impacts.

[GaWx]

2 hours ago, StantonParkHoya said:

From a sensible weather standpoint, it doesn’t really matter much, it’s generally the same impacts.

Regarding the potential low forming off the SE:

AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
445 PM EDT THU SEP 12 2024

SATURDAY AND SUNDAY: AS MUCH OF THE FORECAST STILL DEPENDS ON  
WHETHER THIS LOW PRESSURE DEVELOPS OFF OF THE SE COAST, HIGH  
UNCERTAINTY STILL EXISTS. ALL THE MODELS ARE PLAYING OUT A  
DIFFERENT SCENARIO AS TO IF AND WHEN THE LOW DEVELOPS, AND HOW  
STRONG IT IS GOING TO BE. NHC HAS A 30% OF TROPICAL DEVELOPMENT  
FOR THIS LOW ON THEIR 7-DAY TROPICAL OUTLOOK. TO SAY THE LEAST,  
THERE IS A LOT TO DETERMINE IN THE NEXT COUPLE OF DAYS.


LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/  

HIGH UNCERTAINTY EXISTS IN THE LONG TERM PERIOD, ESPECIALLY WITH THE  
DETAILS OF THE TIMING, PLACEMENT, AND INTENSITY OF A POTENTIAL  
COASTAL LOW PRESSURE.

 

 

 

[BombsAway1288]

This one needs to be watched obviously.
 

As others have said, this type of pattern gives the models fits and the type that could have a system pop up with a very short lead time, kinda like Francine 

[calm_days]

HRRR was accurate with, even the unusual shape and timing of Debby this year and some of the other Mid Atlantic development in earlier years.  That does not mean it is accurate this time but so far it looks like whatever this is. 

[GaWx]

 9/12/24 Euro Weeklies mean ACE progs (% of climo for the week) (Euro climo based on 2004-23):

9/16-22: 6 (40%)(has been BN)

9/23-29: 14 (110%)(has been NN)

9/30-10/6: 16 (170%)(has been AN)(16 is climo of peak week of 9/9-15)

10/7-13: 10 (140%)(has been AN)

- So, the week of 9/30-10/6 is forecasted by the current Weeklies to be the busiest in terms of ACE. This run is essentially predicting peak climo ACE 3 weeks late despite 9/30-10/6 climo already being down 40% from its peak!

- As the above shows along with prior runs, the Weeklies have been consistent with a BN late Aug through mid Sept, a NN late Sept, and AN 1st 2 weeks of Oct. So, these signals are rather strong.

- This is the 4th run in a row having 9/30-10/6 the busiest week.

- So, this run is predicting ACE to be ~107 as of Oct 13th. (I added a point for 9/13-5 though there may be none.)

 

[Windspeed]

Hrmm... 94L is looking quite interesting this morning. Against low odds, the previous light convective bursting has finally given way to deeper persistent convection overnight. This invest already had a small vortex. The disturbance had just failed to maintain any prolonged convection with a notable west wind at the surface on ASCAT. That may be changing, however. Could this be a real player now? Modeling support has remained abysmal.

[yoda]

7 minutes ago, Windspeed said:

Hrmm... 94L is looking quite interesting this morning. Against low odds, the previous light convective bursting has finally given way to deeper persistent convection overnight. This invest already had a small vortex. The disturbance had just failed to maintain any prolonged convection with a notable west wind at the surface on ASCAT. That may be changing, however. Could this be a real player now? Modeling support has remained abysmal.

Funny... cause NHC basically wrote it off in the 2am TWO 

1.. Near the Northern Leeward Islands (AL94):

Satellite-derived wind data from several hours ago indicate that 
a small area of low pressure located less than one hundred miles 
east of the northern Leeward Islands has degenerated into a surface 
trough. Environmental conditions, including the proximity of dry 
air, do not favor development of this system while it moves 
west-northwestward at about 15 mph. Regardless of development, 
locally heavy rainfall and gusty winds are possible across the 
northern Leeward Islands today.
* Formation chance through 48 hours...low...20 percent. 
* Formation chance through 7 days...low...20 percent.

[NorthHillsWx]

Our stream of land falling named systems may continue. TD7 looks like it has a chance to steal a name this morning but that’s not a certainty any more, and it looks increasingly hostile ahead of it. One word sums up the Atlantic over the next week: Meh

[CurlyHeadBarrett]

2 hours ago, NorthHillsWx said:

Our stream of land falling named systems may continue. TD7 looks like it has a chance to steal a name this morning but that’s not a certainty any more, and it looks increasingly hostile ahead of it. One word sums up the Atlantic over the next week: Meh

 

Spoke too soon bhai:

 

Tropical Storm SEVEN
As of 12:00 UTC Sep 13, 2024:
 

Location: 19.2°N 38.3°W
Maximum Winds: 35 kt  Gusts: N/A
Minimum Central Pressure: 1006 mb
Environmental Pressure: N/A
Radius of Circulation: N/A
Radius of Maximum wind: 30 nm
34 kt Wind Radii by Quadrant:

[CurlyHeadBarrett]

JFL 

AL, 07, 2024091312, , BEST, 0, 192N, 383W, 35, 1006, TS, 34, NEQ, 60, 0, 0, 0, 1012, 120, 30, 0, 0, L, 0, , 0, 0, GORDON, M, 0, , 0, 0, 0, 0, genesis-num, 020,

[WxWatcher007]

2 hours ago, NorthHillsWx said:

Our stream of land falling named systems may continue. TD7 looks like it has a chance to steal a name this morning but that’s not a certainty any more, and it looks increasingly hostile ahead of it. One word sums up the Atlantic over the next week: Meh

Meh is right. Maybe the Euro weeklies will be right in shifting the peak season ACE to ~Sept 23-mid October but I’ve written off the MDR at this point. 

Also, for all the NHC names everything crowd out there, 94L says hello.  

[TheDreamTraveler]

When was the last time we saw a September this inactive, 2014? We still have half of the month to go but things aren't looking too good. Still could change come end of September into October but I'm really starting to doubt a sudden uptick happening anymore

[GaWx]

37 minutes ago, TheDreamTraveler said:

When was the last time we saw a September this inactive, 2014? We still have half of the month to go but things aren't looking too good. Still could change come end of September into October but I'm really starting to doubt a sudden uptick happening anymore

 This was a Euro Weeklies post I made on Aug 27:

“Today’s Euro Weeklies could be nicknamed “A Tale of Two Seasons”:

- Weeks 1-3 (9/2-22): remain only at ~50% of climo overall. These haven’t changed much for days other than a gradual decline.

- Week 4 (9/23-29/new week “on the block”): the first forecast for that week is for 120% of climo and it follows the prior week’s modest 70%. So, it’s seeing some kind of sudden change. If it were a reversion to climo, it would be only at 100%, not 120%. Also, this is the first time there has been any week at 120%+ since the 8/16 run.”

And on Sep 3 I posted this when 9/30-10/6 first appeared on the Weeklies: that week was quite active on this even back then.

 

[GaWx]

Highest ACE After 9/12 for 1951+: implies ceiling of ~124
 

1998: 124 (57 prior)

2020: 118 (62 prior)

2005: 110 (135 prior)

2017: 96 (129 prior)

1961: 95 (94 prior)

2016: 94 (46 prior)

1999: 87 (89 prior)

2010: 81 (84 prior)

1963: 80 (32 prior)

2004: 78 (149 prior)

  
 As of Sep 12th, 2024 has had ACE of 60. Prior to 2024 the last two La Niña seasons immediately following a super strong El Niño were 2016 and 1998. Note that although they both ended up with well above average ACE, neither was above average as of Sep 12th: 

- 1998 had 57 as of Sep 12th, very similar to 2024. It had the largest post Sep 12th since 1951 with 124 to give it a season total way up at 181. However, Georges became a H on Sep 17 and a MH on Sep 19. So, it’s soon going to be very hard to keep up with 1998.

- 2016 had only 46 as of Sep 12th, well under 2024’s 60. But due to a very active post Sep 12th of 94, it ended the season with 140. It was able to do this even though the next H wasn’t until Sep 29th. So, matching 2016 seems doable if the Euro Weeklies for late Sep-early Oct are onto something and considering 2024 was 14 higher on Sep 12th. So, it seems to me that 2024 ending up with ACE near 150 is still quite possible:

[Windspeed]

Meh is right. Maybe the Euro weeklies will be right in shifting the peak season ACE to ~Sept 23-mid October but I’ve written off the MDR at this point. 
Also, for all the NHC names everything crowd out there, 94L says hello.  

94L has been a pestering nuisance. I kept waving it off. But it kept pulsing convection just enough. Glad it's finally squashed.

Gordon is an excellent example of the continued unusual stable state of the MDR during peak ASO. Typically, by mid-September, we see higher latitude CV systems that go through TCG eventually go on to thrive in the central Atlantic to reach hurricane intensity. But Gordon isn't impressing me much.

Interesting comments/thread by Webb on reinforced stability across the MDR by a strengthening Summer +NAO here:

[jbenedet]

Kind of funny reading through these comments while the op GFS is showing run after run of a land falling TC/STC in the Carolina’s within D4. 
 

But zzzzzz away….

[WxWatcher007]

20 minutes ago, jbenedet said:

Kind of funny reading through these comments while the op GFS is showing run after run of a land falling TC/STC in the Carolina’s within D4. 
 

But zzzzzz away….

I’ve been talking about the window for development off the SE coast since late August. 99L was the first manifestation of that window. The window has stayed open despite the oscillating model signals and now we have this orange that does look increasingly likely to do something. Probably will start a thread shortly. 

[Seminole]

3 hours ago, Windspeed said:

 

94L has been a pestering nuisance. I kept waving it off. But it kept pulsing convection just enough. Glad it's finally squashed.

Gordon is an excellent example of the continued unusual stable state of the MDR during peak ASO. Typically, by mid-September, we see higher latitude CV systems that go through TCG eventually go on to thrive in the central Atlantic to reach hurricane intensity. But Gordon isn't impressing me much.

Interesting comments/thread by Webb on reinforced stability across the MDR by a strengthening Summer +NAO here:

 

 

 

Interesting that the anomalous readings this year are located in the vicinity where the ITCZ moved to. I believe the ITCZ was cited as misplaced 150 miles north of where it normally is.  

[cptcatz]

I'm watching the southwest Caribbean next weekend.  All models are hinting at something forming and moving north.  

[WxWatcher007]

52 minutes ago, cptcatz said:

I'm watching the southwest Caribbean next weekend.  All models are hinting at something forming and moving north.  

Yep, maybe a CAG signal there. I think this is a ripe pattern for something along the eastern Gulf or East Coast. 

[Windspeed]

[Stormchaserchuck1]

There have been plenty of active seasons with +NAO's before.  The thing is, Sept 12th is midway through the season and we are on "G", which is the 7th storm. On pace for 13-14. For a very long time, the Atlantic average 9 NS/yr. The better thing to look at is "what wasn't anomalous this season". Assume that the last 30 years have been an anomaly, with the Atlantic having 180% ACE, and the whole globe together having 74% ACE. 

[GaWx]

49 minutes ago, Stormchaserchuck1 said:

There have been plenty of active seasons with +NAO's before.  The thing is, Sept 12th is midway through the season and we are on "G", which is the 7th storm. On pace for 13-14. For a very long time, the Atlantic average 9 NS/yr. The better thing to look at is "what wasn't anomalous this season". Assume that the last 30 years have been an anomaly, with the Atlantic having 180% ACE, and the whole globe together having 74% ACE. 

I don’t see a clearcut correlation of NAO with Atlantic tropical activity. Look no further than 2018, way more +NAO than 2024 and the most +NAO hurricane season on record. Yet, it had Michael, Florence, and a total of 8H/15NS. 1979 had David and Frederic. Aug/Sep of 2005 were both +NAO. The most +NAO Sep on record (over +2!), 1989, had Hugo. 1995 was dominated by a +NAO. Sep of 2020 had a +NAO and 10 NS, etc. No correlation of +NAO with less activity looking at the hard data.

 In addition, the US has already had 3 H hits, more than the avg for the entire season!

[Stormchaserchuck1]

+NAO has a slight correlation with higher SLP and cooler SSTs. I guess this is what they are referring to

In September, the wavelengths are so short that there is actually a slight lower SLP correlation in the hotter tropical region

We should be having a -NAO by late September

[GaWx]

 The model consensus is suggesting that after the current NE Rex block breaks down and Invest 95L goes inland that there could be a similar 2nd one during the 6-10 blocking things up again. Thereafter, the ensembles suggest a TC moving NE from the W Caribbean (which could be very strong) across or just E of FL is quite possible as the pattern changes to more autumn-like. It wouldn’t be a shocker if that would be the next MH based on its modeled origins. Increased activity then would be consistent with the Euro Weeklies. Based on the Weeklies, more activity originating from the W Caribbean or Gulf would be quite possible the week after that.

[GaWx]

The various ensembles overall continue to look fairly active for late Sept. with FL possibly in the crosshairs from a Caribbean originating storm. 

[GaWx]

 Note what looks like a circulation near 32N, 70W. This came from that further east convection that was separate from PTC8. It likely will never amount to much, regardless, though it is interesting to see.