2023 Indicators (SST, SAL, MSLP, Wind shear, Steering, Instability) and Day 16+ Models

[REDHurricane]

Look back during the major hurricane drought. Same thing, just different. Everyone is convinced something has changed and everything will be different, and yet the same as it is now. These posts will look foolish a few years from now, just like 2013 redo predictions look foolish at the start of a busy season.

Predict slow season, get strong season, overreact.
Predict strong season, get slow season, overreact.

Works well on social media only.

While it is a mistake to make sweeping generalizations about the future based on the results of any individual hurricane season, it is an equally significant mistake to ignore clear evidence that tropical cyclone frequency/intensity is trending a certain direction over the span of decades, especially when there is an obvious and measurable scientific explanation behind the trend's existence. Yeah, our limited historical TC data beyond the past ~100 years makes it impossible to know precisely to what extent tropical activity on Earth has typically fluctuated on a century-to-century basis, but it doesn't take a PhD in climate science to realize that record high (and still rising) global SSTs are probably going to lead to a notable increase in the length/strength of the average hurricane season as time goes on.

[weeniepatrol]

We are getting uncomfortably low on names.

Imagine we exhaust the list - during a strengthening El Nino.

it's only 23 September btw!!!

[Category5Kaiju]

We are getting uncomfortably low on names.

Imagine we exhaust the list - during a strengthening El Nino.

it's only 23 September btw!!!

Atlantic was really like "El Nino my ass" this year lol

[WalterWhite]

The fact that Idalia, a major hurricane, formed from the Central American Gyre in August makes me think the peak Central American Gyre season, which is usually in October, will be pretty active. Additionally, wind shear in the Western Atlantic has been near-average despite the El Niño, and SSTs in that region of the Atlantic are well above-average, with most of the Gulf of Mexico and the Caribbean at or above 30 degrees Celsius. I would not be surprised if we get multiple major hurricanes originating from the Central American Gyre during October and November.

Major hurricanes in August usually form from tropical waves. In 2021, Grace and Ida formed from tropical waves originating from East Africa. In 2020, Laura formed from a tropical wave originating from East Africa. The same applies to Dorian (2019); Harvey (2017); Gaston (2016); Danny (2015); Irene (2011); Danielle and Earl (2010); Bill (2009); Gustav (2008); Dean (2007); Katrina (2005); Alex, Charley, and Frances (2004); Fabian (2003); Alberto (2000); Bret and Cindy (1999); Bonnie (1998); Edouard and Fran (1996); Felix and Luis (1995); Emily (1993); Andrew (1992); Gustav (1990); Elena (1985); Allen (1980); David (1979); Anita (1977); Belle and Frances (1976); Carolina (1975); Celia (1970); and Camille and Debbie (1969). Bob (1991), Alicia (1983), and Becky (1974) all originated from non-tropical origins.

In other words, Major Hurricane Idalia (2023) is the first August major hurricane formed from the Central American Gyre in this satellite era. Because climatology dictates that the Central American Gyre usually peaks in October, we could see enhanced Central American Gyre activity during the late season.

With this in mind, October could be a very destructive month for this hurricane season. Major hurricanes in either the Gulf of Mexico and the Caribbean always bring destruction somewhere (whether it is Florida, Louisiana, Texas, Hispaniola, or Central America).

[cycloneye]

More records for the 2023 season.

 https://twitter.com/philklotzbach/status/1705698172465750297

[aspen]

We are getting uncomfortably low on names.

Imagine we exhaust the list - during a strengthening El Nino.

it's only 23 September btw!!!

We’re probably hitting 20 NS at this rate, unless we see a near-total shutdown of activity after September, which I think could be possible. The ocean and atmo have to synch up eventually.

[Teban54]

What's more impressive than the number of storms alone is that their qualities aren't lacking.

The 12 storms that formed since August 20 this year were 12/5/3, whereas the ones in 2020 were 12/6/2. Many forum members here believe that Jose and Ophelia could have been unofficial hurricanes, which would have brought the total to 12/7/3.

We've had a Cat 5 (which 2020 lacked), a 130 kt Cat 4 that nobody expected to happen, and yet another Gulf RI'ing Cat 4. We had 3 classic CV storms that became hurricanes this year, while 2020 had 2. Even many of the (official) TSes were memorable: Gert somehow managed to hang around forever and outlive all 5 other August storms, Jose had dual rotating hot towers and might have been one of the smallest hurricanes on record, and Ophelia went from a frontal low to almost a hurricane in the blink of an eye.

These 12 storms have generated 101.6 ACE to date, and Philippe's story has only just begun. Those 12 storms in 2020 generated about 81.4 ACE. (I used CSU for 2023 and Ryan Maue's website for 2020, so there could be some inaccuracies.)

The fact that an El Nino year is even comparable in some capacity to the most active season on record at all is bonkers.

[al78]

We are getting uncomfortably low on names.

Imagine we exhaust the list - during a strengthening El Nino.

it's only 23 September btw!!!

We’re probably hitting 20 NS at this rate, unless we see a near-total shutdown of activity after September, which I think could be possible. The ocean and atmo have to synch up eventually.

Normally during a moderate or strong El Nino I would expect activity to die off as we go into October given the typical high wind shear over the Caribbean Sea seen during El Nino events. This year the Atlantic hurricane season seems to have little interest in El Nino given the atmosphere/Walker circulation has not exhibited a typical response so who knows what the near future holds.

[al78]

Look back during the major hurricane drought. Same thing, just different. Everyone is convinced something has changed and everything will be different, and yet the same as it is now. These posts will look foolish a few years from now, just like 2013 redo predictions look foolish at the start of a busy season.

Predict slow season, get strong season, overreact.
Predict strong season, get slow season, overreact.

Works well on social media only.

While it is a mistake to make sweeping generalizations about the future based on the results of any individual hurricane season, it is an equally significant mistake to ignore clear evidence that tropical cyclone frequency/intensity is trending a certain direction over the span of decades, especially when there is an obvious and measurable scientific explanation behind the trend's existence. Yeah, our limited historical TC data beyond the past ~100 years makes it impossible to know precisely to what extent tropical activity on Earth has typically fluctuated on a century-to-century basis, but it doesn't take a PhD in climate science to realize that record high (and still rising) global SSTs are probably going to lead to a notable increase in the length/strength of the average hurricane season as time goes on.

If SSTs continue to warm in the coming decades it depends on how the atmosphere responds, but I would expect an upward trend in rapid intensification events and numbers of cat 4/5 tropical cyclones (although it will be hard to detect this at least initially due to the small numbers climatologically), even if the atmosphere becomes more hostile on average. There will still be ENSO and periods when atmospheric conditions are optimal, and it only takes a vigorous tropical wave in the right place at the right time to get a Cat 5.

[kevin]

So far the 2023 open ocean MDR/CV season is incredible. Here an overview of how many MDR storms we've had since 2000. Here I count the MDR as everything west of the islands (so not the Caribbean) and between 10N and 20N. The system must've at least been a TD before reaching the islands (60W) to count. With 10 MDR storms 2023 has the most MDR storms of any season since at least 2000 (haven't checked before that) and the season isn't even over yet. And also after 2004 it has the highest percentage of MDR storms. 2005 for example was very active, but had an almost non-existent MDR with more activity in the WCar and the Gulf. The same goes for last year. The only thing that 2023 is still lacking is a high hurricane or MH count in the MDR like 2004. However, with Philippe and 91L it's not out of the question that we'll at least get 5 MDR hurricanes this season.

Year / MDR TS / MDR HU / MDR MH / MDR C5 / Percentage of all storms

2023 / 10 / 3 / 1 / 1 / 59%
2022 / 3 / 2 / 1 / 0 / 21%
2021 / 8 / 4 / 3 / 0 / 38%
2020 / 9 / 4 / 2 / 0 / 30%
2019 / 6 / 3 / 2 / 2 / 33%
2018 / 6 / 4 / 1 / 0 / 40%
2017 / 6 / 5 / 4 / 2 / 35%
2016 / 6 / 2 / 1 / 1 / 38%
2015 / 5 / 2 / 1 / 0 / 45%
2014 / 3 / 3 / 2 / 0 / 38%
2013 / 4 / 1 / 0 / 0 / 29%
2012 / 9 / 4 / 0 / 0 / 47%
2011 / 5 / 5 / 3 / 0 / 26%
2010 / 9 / 6 / 4 / 0 / 47%
2009 / 5 / 2 / 2 / 0 / 56%
2008 / 5 / 3 / 2 / 0 / 31%
2007 / 5 / 3 / 2 / 2 / 33%
2006 / 5 / 3 / 2 / 0 / 50%
2005 / 5 / 4 / 2 / 1 / 18%
2004 / 9 / 7 / 5 / 1 / 60%
2003 / 6 / 4 / 3 / 1 / 38%
2002 / 2 / 1 / 1 / 0 / 17%
2001 / 5 / 3 / 3 / 0 / 33%
2000 / 7 / 4 / 2 / 0 / 47%
Average / 6 / 3 / 2 / 0

[WalterWhite]

The CFSv2 is indicating below-average MSLPs throughout the tropical Atlantic during the entirely of October and the first half of November.









Lower MSLPs throughout the tropical Atlantic generally indicate favorable conditions, so this hurricane season could realistically run until mid-November.

[Category5Kaiju]

The CFSv2 is indicating below-average MSLPs throughout the tropical Atlantic during the entirely of October and the first half of November.

https://i.postimg.cc/k5CVKbJG/cfs-avg-mslpa-Norm-Mean-atl-3.png

https://i.postimg.cc/FRW1MCjk/cfs-avg-mslpa-Norm-Mean-atl-4.png

https://i.postimg.cc/j2DCt6Xg/cfs-avg-mslpa-Norm-Mean-atl-5.png

https://i.postimg.cc/0jhjQ6X8/cfs-avg-mslpa-Norm-Mean-atl-6.png

Lower MSLPs throughout the tropical Atlantic generally indicate favorable conditions, so this hurricane season could realistically run until mid-November.

2023 about to hit the auxiliary list (or basically what used to be the Greek alphabet) during a moderate El Nino year

[MarioProtVI]

So far the 2023 open ocean MDR/CV season is incredible. Here an overview of how many MDR storms we've had since 2000. Here I count the MDR as everything west of the islands (so not the Caribbean) and between 10N and 20N. The system must've at least been a TD before reaching the islands (60W) to count. With 10 MDR storms 2023 has the most MDR storms of any season since at least 2000 (haven't checked before that) and the season isn't even over yet. And also after 2004 it has the highest percentage of MDR storms. 2005 for example was very active, but had an almost non-existent MDR with more activity in the WCar and the Gulf. The same goes for last year. The only thing that 2023 is still lacking is a high hurricane or MH count in the MDR like 2004. However, with Philippe and 91L it's not out of the question that we'll at least get 5 MDR hurricanes this season.

Year / MDR TS / MDR HU / MDR MH / MDR C5 / Percentage of all storms

2023 / 10 / 3 / 1 / 1 / 59%
2022 / 3 / 2 / 1 / 0 / 21%
2021 / 8 / 4 / 3 / 0 / 38%
2020 / 9 / 4 / 2 / 0 / 30%
2019 / 6 / 3 / 2 / 2 / 33%
2018 / 6 / 4 / 1 / 0 / 40%
2017 / 6 / 5 / 4 / 2 / 35%
2016 / 6 / 2 / 1 / 1 / 38%
2015 / 5 / 2 / 1 / 0 / 45%
2014 / 3 / 3 / 2 / 0 / 38%
2013 / 4 / 1 / 0 / 0 / 29%
2012 / 9 / 4 / 0 / 0 / 47%
2011 / 5 / 5 / 3 / 0 / 26%
2010 / 9 / 6 / 4 / 0 / 47%
2009 / 5 / 2 / 2 / 0 / 56%
2008 / 5 / 3 / 2 / 0 / 31%
2007 / 5 / 3 / 2 / 2 / 33%
2006 / 5 / 3 / 2 / 0 / 50%
2005 / 5 / 4 / 2 / 1 / 18%
2004 / 9 / 7 / 5 / 1 / 60%
2003 / 6 / 4 / 3 / 1 / 38%
2002 / 2 / 1 / 1 / 0 / 17%
2001 / 5 / 3 / 3 / 0 / 33%
2000 / 7 / 4 / 2 / 0 / 47%
Average / 6 / 3 / 2 / 0

Lee’s been the only MDR hurricane so far. Not sure where the other two are from considering the definition is 10N-20N. Maybe Bret as well if it gets a bump in TCR.

[kevin]

So far the 2023 open ocean MDR/CV season is incredible. Here an overview of how many MDR storms we've had since 2000. Here I count the MDR as everything west of the islands (so not the Caribbean) and between 10N and 20N. The system must've at least been a TD before reaching the islands (60W) to count. With 10 MDR storms 2023 has the most MDR storms of any season since at least 2000 (haven't checked before that) and the season isn't even over yet. And also after 2004 it has the highest percentage of MDR storms. 2005 for example was very active, but had an almost non-existent MDR with more activity in the WCar and the Gulf. The same goes for last year. The only thing that 2023 is still lacking is a high hurricane or MH count in the MDR like 2004. However, with Philippe and 91L it's not out of the question that we'll at least get 5 MDR hurricanes this season.

Year / MDR TS / MDR HU / MDR MH / MDR C5 / Percentage of all storms

2023 / 10 / 3 / 1 / 1 / 59%
2022 / 3 / 2 / 1 / 0 / 21%
2021 / 8 / 4 / 3 / 0 / 38%
2020 / 9 / 4 / 2 / 0 / 30%
2019 / 6 / 3 / 2 / 2 / 33%
2018 / 6 / 4 / 1 / 0 / 40%
2017 / 6 / 5 / 4 / 2 / 35%
2016 / 6 / 2 / 1 / 1 / 38%
2015 / 5 / 2 / 1 / 0 / 45%
2014 / 3 / 3 / 2 / 0 / 38%
2013 / 4 / 1 / 0 / 0 / 29%
2012 / 9 / 4 / 0 / 0 / 47%
2011 / 5 / 5 / 3 / 0 / 26%
2010 / 9 / 6 / 4 / 0 / 47%
2009 / 5 / 2 / 2 / 0 / 56%
2008 / 5 / 3 / 2 / 0 / 31%
2007 / 5 / 3 / 2 / 2 / 33%
2006 / 5 / 3 / 2 / 0 / 50%
2005 / 5 / 4 / 2 / 1 / 18%
2004 / 9 / 7 / 5 / 1 / 60%
2003 / 6 / 4 / 3 / 1 / 38%
2002 / 2 / 1 / 1 / 0 / 17%
2001 / 5 / 3 / 3 / 0 / 33%
2000 / 7 / 4 / 2 / 0 / 47%
Average / 6 / 3 / 2 / 0

Lee’s been the only MDR hurricane so far. Not sure where the other two are from considering the definition is 10N-20N. Maybe Bret as well if it gets a bump in TCR.

Lee, Margot and Nigel. My definition for that list is any storm which formed within the MDR, which Margot and Nigel also meet despite only reaching hurricane strength during their recurve outside of the MDR. The same goes for all years in the overview though so it's still a fair comparison.

[WalterWhite]

For some reason, wind shear seems to be unfavorable throughout most of the Atlantic basin.

[tolakram]

For some reason, wind shear seems to be unfavorable throughout most of the Atlantic basin.

https://i.postimg.cc/W1KW0f7p/wg8shr.gif

El Nino finally starting to win the battle. Maybe. Models show unfavorable wind shear in the future as well, but the model shear forecasts can be horribly inaccurate. If el nino does start winning I still expect a lot of storms to spin up when they find favorable spots. We shall see.

[WalterWhite]

For some reason, wind shear seems to be unfavorable throughout most of the Atlantic basin.

https://i.postimg.cc/W1KW0f7p/wg8shr.gif

El Nino finally starting to win the battle. Maybe. Models show unfavorable wind shear in the future as well, but the model shear forecasts can be horribly inaccurate. If el nino does start winning I still expect a lot of storms to spin up when they find favorable spots. We shall see.

The fact that wind shear is very low throughout the Gulf of Mexico and certain portions of the Caribbean makes me think it is not because of the El Nino but rather something else.

[zzzh]

Yep, El Nino with huge ULAC over the Caribbean?

[Ubuntwo]

The fact that Idalia, a major hurricane, formed from the Central American Gyre in August makes me think the peak Central American Gyre season, which is usually in October, will be pretty active. Additionally, wind shear in the Western Atlantic has been near-average despite the El Niño, and SSTs in that region of the Atlantic are well above-average, with most of the Gulf of Mexico and the Caribbean at or above 30 degrees Celsius. I would not be surprised if we get multiple major hurricanes originating from the Central American Gyre during October and November.

Major hurricanes in August usually form from tropical waves. In 2021, Grace and Ida formed from tropical waves originating from East Africa. In 2020, Laura formed from a tropical wave originating from East Africa. The same applies to Dorian (2019); Harvey (2017); Gaston (2016); Danny (2015); Irene (2011); Danielle and Earl (2010); Bill (2009); Gustav (2008); Dean (2007); Katrina (2005); Alex, Charley, and Frances (2004); Fabian (2003); Alberto (2000); Bret and Cindy (1999); Bonnie (1998); Edouard and Fran (1996); Felix and Luis (1995); Emily (1993); Andrew (1992); Gustav (1990); Elena (1985); Allen (1980); David (1979); Anita (1977); Belle and Frances (1976); Carolina (1975); Celia (1970); and Camille and Debbie (1969). Bob (1991), Alicia (1983), and Becky (1974) all originated from non-tropical origins.

In other words, Major Hurricane Idalia (2023) is the first August major hurricane formed from the Central American Gyre in this satellite era. Because climatology dictates that the Central American Gyre usually peaks in October, we could see enhanced Central American Gyre activity during the late season.

With this in mind, October could be a very destructive month for this hurricane season. Major hurricanes in either the Gulf of Mexico and the Caribbean always bring destruction somewhere (whether it is Florida, Louisiana, Texas, Hispaniola, or Central America).

I am of the opinion Idalia formed from a segment of the monsoon trough crossing over from the EPAC due to troughing. Mets on twitter never really moved past the 'psuedo-central american gyre' phrasing and the NHC never explicitly mentioned a CAG. Not to mention there are no CAG events on record for the month of August. I would also hesitate to assume that early season CAG activity correlates w/ late season CAG activity.

[Hurricane Mike]

The fact that Idalia, a major hurricane, formed from the Central American Gyre in August makes me think the peak Central American Gyre season, which is usually in October, will be pretty active. Additionally, wind shear in the Western Atlantic has been near-average despite the El Niño, and SSTs in that region of the Atlantic are well above-average, with most of the Gulf of Mexico and the Caribbean at or above 30 degrees Celsius. I would not be surprised if we get multiple major hurricanes originating from the Central American Gyre during October and November.

Major hurricanes in August usually form from tropical waves. In 2021, Grace and Ida formed from tropical waves originating from East Africa. In 2020, Laura formed from a tropical wave originating from East Africa. The same applies to Dorian (2019); Harvey (2017); Gaston (2016); Danny (2015); Irene (2011); Danielle and Earl (2010); Bill (2009); Gustav (2008); Dean (2007); Katrina (2005); Alex, Charley, and Frances (2004); Fabian (2003); Alberto (2000); Bret and Cindy (1999); Bonnie (1998); Edouard and Fran (1996); Felix and Luis (1995); Emily (1993); Andrew (1992); Gustav (1990); Elena (1985); Allen (1980); David (1979); Anita (1977); Belle and Frances (1976); Carolina (1975); Celia (1970); and Camille and Debbie (1969). Bob (1991), Alicia (1983), and Becky (1974) all originated from non-tropical origins.

In other words, Major Hurricane Idalia (2023) is the first August major hurricane formed from the Central American Gyre in this satellite era. Because climatology dictates that the Central American Gyre usually peaks in October, we could see enhanced Central American Gyre activity during the late season.

With this in mind, October could be a very destructive month for this hurricane season. Major hurricanes in either the Gulf of Mexico and the Caribbean always bring destruction somewhere (whether it is Florida, Louisiana, Texas, Hispaniola, or Central America).

Good statistics. Yeah, Idalia was a rarity coming out of the CAG in August.