2018 Indicators: SST's / MSLP / Sal / Steering / Shear / Instability (Graphic updates at first post)

[Shell Mound]

Anny and especially One does not have westerly anomalies

Alberto did. No doubt about that. The tropical Atlantic still produced numerous storms that year. That niño wasn't very strong. The high latitudes only produced 2 though. Both in July

Thank you for correcting me about TS One (1968), but Abby does seem to exhibit some weak westerly anomalies. Anyway, out of the years that I posted, 1972 and 1982 featured full-basin El Niño episodes, so those years are not good analogs for 2018. 1968 is interesting: it did not feature a classic +PMM (note the cold near Baja California), and there was a clear +PDO, but did exhibit warmth near Hawaii, and El Niño was certainly west-based, based on the data I found. Neither was 2006 a true Modoki event, as there was no +PMM, but there was a -PDO. If we do not see El Niño in time for the peak of the 2018 Atlantic hurricane season, I wonder if the next -NAO episode will bring a dramatic turnabout in the MDR, with a significant warming similar to what we saw in 2017, even if the SSTs do not end up nearly as warm as in 2017.

[Kingarabian]

JMA is pretty dry for July-August:

 https://twitter.com/BenNollWeather/status/997157538356453377

[Sciencerocks]

JMA is pretty dry for July-August:

 https://twitter.com/BenNollWeather/status/997157538356453377

Yep, both dry air and surface pressure support a slower season as I was saying earlier. I don't think it will be as slow as 2009 but 2012, 2013, 2014 is certainly possible.

[NotSparta]

JMA is pretty dry for July-August:

 https://twitter.com/BenNollWeather/status/997157538356453377

Yep, both dry air and surface pressure support a slower season as I was saying earlier. I don't think it will be as slow as 2009 but 2012, 2013, 2014 is certainly possible.

2013 was slower than 2009

[Sciencerocks]

JMA is pretty dry for July-August:

 https://twitter.com/BenNollWeather/status/997157538356453377

Yep, both dry air and surface pressure support a slower season as I was saying earlier. I don't think it will be as slow as 2009 but 2012, 2013, 2014 is certainly possible.

2013 was slower than 2009

Depends on how you measure it If you're measuring by named storms 2013 was busier, if it is ace or hurricanes then 2009 was.
2009 had 9 named storms
2013 had 14 named storms

That is what I was thinking about but you're right as 2009 clearly had more energy with Hurricane Bill and Fred.

[TheStormExpert]

Here is the May update of MSLP for ASO and wow,if this pans out MDR / Caribbean / GOM will shut down. But in 2017 it had this and we know and I endured it directly what occured.

In May 2017 is when the Euro finally started to show signs of favorability across the Atlantic for the 2017 season, that is not the case this May fortunately.

[StruThiO]

According to this, the subtropical warm blob is even warmer than you think

 https://twitter.com/NOAANCEIclimate/status/997135950064111617

[cycloneye]

@MJVentrice
April 2018 North Atlantic sea-surface temperature anomalies couldn't be more opposite compared to April 2005. The Atlantic Meridional Mode (AMM) index was a +3.82 in April 2005; It was -2.9 in April 2018.

 https://twitter.com/MJVentrice/status/997455249521639429

[Shell Mound]

At this time in 2017, the tropical Atlantic was the warmest relative to the other basins globally. This year, it's the coldest. (The subtropical North Atlantic is the warmest; the EPAC north of the equator, second.) Between now and ASO, a big change will need to happen just to get the MDR back to slightly above average. A very persistent -NAO is but one of several factors that will need to align for this to happen. Combined with the very strong +PMM, the very -AMO signature, were it to persist, could well contribute to a much more inactive season than people are anticipating. Right now, the Atlantic is in the most -AMO signature I have seen in a very long time.

[LarryWx]

Here is the May update of MSLP for ASO and wow,if this pans out MDR / Caribbean / GOM will shut down. But in 2017 it had this and we know and I endured it directly what occured.

https://i.imgur.com/8yOUkw6.png

In addition to 2017, tt would be really informative if we had access to or at least clear memories of past May Euro forecasts for ASO and then compared these to how the seasons went. Was 2017 reflective of a common Euro error/bias or was 2017 a rare error? Does anyone have access to or memories of 2016 and earlier May Euro forecasts for ASO?

Larry You can find it in the link below. Goes back to 2008.

EUROSIP

Thanks. That's nice to be able to see. So, I took a careful look at these Euro ASO SLP forecasts going back to 2008 and learned a lot. Here's what I found regarding past Euro ASO SLP forecasts made in May (June in 2008):

1. The 2018 May forecast is the 2nd least active forecast since 2008 with only 2009 barely less active overall (and even that's debatable). It is a much less active forecast than 2017's, which was actually pretty much neutral in the Car./GOM.

2. I compared these May forecasts with actual ASO TC activity and here are my grades:

2017: D (worst of any); forecast was neutral GOM/Car./slightly quieter than normal elsewhere except more solidly quieter than normal E to S MDR
2016: B; overall pretty neutral forecast W MDR/GOM/subtropics but inactive E MDR
2015: B; forecast pretty inactive tropics but near normal subtropics
2014: A; forecast inactive tropics but near normal subtropics; 2nd least active of any back to 2008 excluding 2018
2013: C; forecast pretty neutral everywhere
2012: C; forecast pretty inactive most of MDR/GOM but neutral much of subtropics E of 60W
2011: B; forecast pretty active most of MDR/GOM/subtropics west of 60W, especially E MDR, but neutral subtropics E of 60W
2010: A; forecast was the most active of any back to 2008
2009: B; forecast was the least active of any back to 2008
2008: A; forecast was 2nd most active of any back to 2008, including more active N MDR vs S MDR

Average grade B: pretty good and worthy of being followed even though 3 of 10 got a C or D
----------------------------------------------------------------------------------------------------------------------------

May forecasts in order of least active to most active/later ENSO peak/grade


2009: strong Nino/B
2018: ?/?
2014: weak Nino/A
2015: strong Nino/B

2012: warm neutral/C
2016: weak Nina/B
2017: moderate Nina/D
2013: cold neutral/C

2011: moderate Nina/B
2008: weak Nina/A
2010: strong Nina/A

Observations:
- predicted ENSO as of May a big influence on forecast
- performance better overall when forecast near one extreme or the other; note best grades in top and bottom and worst in middle

Conclusion:
With 2018 having the 2nd most inactive forecast since 2008 and considering how the Euro has done in May when near forecast extremes, this May Euro ASO SLP forecast should be taken seriously as far as the chances for a relatively inactive season are concerned even if we get only a weak Nino that shows up late like in 2014.

[Ntxw]

Thanks for the numbers Larry. Shows that sometimes our recollection or memories can sometimes be biased as well compared to actual empirical data. While the forecasts for the Euro (probability) is not always spot on or correct, you can view its trends, can be of use. Also the blanket statement some use that it always forecasts higher than normal pressures is not correct.

[NDG]

In addition to 2017, tt would be really informative if we had access to or at least clear memories of past May Euro forecasts for ASO and then compared these to how the seasons went. Was 2017 reflective of a common Euro error/bias or was 2017 a rare error? Does anyone have access to or memories of 2016 and earlier May Euro forecasts for ASO?

Larry You can find it in the link below. Goes back to 2008.

EUROSIP

Thanks. That's nice to be able to see. So, I took a careful look at these Euro ASO SLP forecasts going back to 2008 and learned a lot. Here's what I found regarding past Euro ASO SLP forecasts made in May (June in 2008):

1. The 2018 May forecast is the 2nd least active forecast since 2008 with only 2009 barely less active overall (and even that's debatable). It is a much less active forecast than 2017's, which was actually pretty much neutral in the Car./GOM.

2. I compared these May forecasts with actual ASO TC activity and here are my grades:

2017: D (worst of any); forecast was neutral GOM/Car./slightly quieter than normal elsewhere except more solidly quieter than normal E to S MDR
2016: B; overall pretty neutral forecast W MDR/GOM/subtropics but inactive E MDR
2015: B; forecast pretty inactive tropics but near normal subtropics
2014: A; forecast inactive tropics but near normal subtropics; 2nd least active of any back to 2008 excluding 2018
2013: C; forecast pretty neutral everywhere
2012: C; forecast pretty inactive most of MDR/GOM but neutral much of subtropics E of 60W
2011: B; forecast pretty active most of MDR/GOM/subtropics west of 60W, especially E MDR, but neutral subtropics E of 60W
2010: A; forecast was the most active of any back to 2008
2009: B; forecast was the least active of any back to 2008
2008: A; forecast was 2nd most active of any back to 2008, including more active N MDR vs S MDR

Average grade B: pretty good and worthy of being followed even though 3 of 10 got a C or D
----------------------------------------------------------------------------------------------------------------------------

May forecasts in order of least active to most active/later ENSO peak/grade


2009: strong Nino/B
2018: ?/?
2014: weak Nino/A
2015: strong Nino/B

2012: warm neutral/C
2016: weak Nina/B
2017: moderate Nina/D
2013: cold neutral/C

2011: moderate Nina/B
2008: weak Nina/A
2010: strong Nina/A

Observations:
- predicted ENSO as of May a big influence on forecast
- performance better overall when forecast near one extreme or the other; note best grades in top and bottom and worst in middle

Conclusion:
With 2018 having the 2nd most inactive forecast since 2008 and considering how the Euro has done in May when near forecast extremes, this May Euro ASO SLP forecast should be taken seriously as far as the chances for a relatively inactive season are concerned even if we get only a weak Nino that shows up late like in 2014.

Larry, one thing I want to point out is that the EUROSIP is a multi model blend used between the Euro, UKMET, NCEP & JMA.
A lot of us refer to the actual ECMWF's forecast which has been most times than not erroneous on MSLPs forecast for the Atlantic.
I would give the ECMWF an "F" on May '17 forecast for ASO, much higher MSLPs than what EUROSIP showed. Unfortunately we can only see going back to 2017 on the ECMWF.

[Kingarabian]

NDG, here's some I found:

ECMWF May 2008 MSLP forecast for JAS 2008:


ECMWF May 2010 MSLP forecast for ASO 2010:


ECMWF May 2016 MSLP forecast for JAS 2016:

[NDG]

NDG, here's some I found:

ECMWF May 2008 MSLP forecast for JAS 2008:
https://i.imgur.com/KbJFzZc.png

ECMWF May 2010 MSLP forecast for ASO 2010:
https://i.imgur.com/JZjxUu3.png

ECMWF May 2016 MSLP forecast for JAS 2016:
https://i.imgur.com/3ov7qLm.png

Thanks, in this case I would also give its 2016 forecast an F.

[Shell Mound]

NDG, here's some I found:

ECMWF May 2008 MSLP forecast for JAS 2008:
https://i.imgur.com/KbJFzZc.png

ECMWF May 2010 MSLP forecast for ASO 2010:
https://i.imgur.com/JZjxUu3.png

ECMWF May 2016 MSLP forecast for JAS 2016:
https://i.imgur.com/3ov7qLm.png

Thanks, in this case I would also give its 2016 forecast an F.

Actually, the 2016 forecast, while not great, verified at least in part. The MDR, on balance, was split between above-average MSLP in the south and below-average MSLP in the north, leading to near-average MSLP on balance. Also, above-average MSLP did verify as advertised over much of the Caribbean, Gulf, and Southeastern U.S. The following graph from JAS 2016 shows that the verification was far from terrible:




The forecasts for JAS 2008 and ASO 2010 verified extremely nicely:






As for the ASO 2017 forecast, it accurately forecast the location of the highest MSLP anomalies, over the eastern MDR, while correctly hinting at (relatively) lower MSLP farther west:





So, considering all the factors that go into seasonal forecasting, the ECMWF is a much more reliable long-range model than people are giving it credit for. At least that's my humble, evidence-based opinion (as I see the evidence).

[NDG]

NDG, here's some I found:

ECMWF May 2008 MSLP forecast for JAS 2008:
https://i.imgur.com/KbJFzZc.png

ECMWF May 2010 MSLP forecast for ASO 2010:
https://i.imgur.com/JZjxUu3.png

ECMWF May 2016 MSLP forecast for JAS 2016:
https://i.imgur.com/3ov7qLm.png

Thanks, in this case I would also give its 2016 forecast an F.

Actually, the 2016 forecast, while not great, verified at least in part. The MDR, on balance, was split between above-average MSLP in the south and below-average MSLP in the north, leading to near-average MSLP on balance. Also, above-average MSLP did verify as advertised over much of the Caribbean, Gulf, and Southeastern U.S. The following graph from JAS 2016 shows that the verification was far from terrible:

[img]https://i.imgur.com/3ov7qLm.png
[img]https://i.imgur.com/MbNPun8.png

The forecasts for JAS 2008 and ASO 2010 verified extremely nicely:

[img]https://i.imgur.com/KbJFzZc.png
[img]https://i.imgur.com/6LkAtNc.png
[img]https://i.imgur.com/JZjxUu3.png
[img]https://i.imgur.com/EhgEnNn.png

As for the ASO 2017 forecast, it accurately forecast the location of the highest MSLP anomalies, over the eastern MDR, while correctly hinting at (relatively) lower MSLP farther west:

[img]https://i.imgur.com/TjkreFj.png
[img]https://i.imgur.com/8jA0eBg.png
[img]https://i.imgur.com/2NAcUmS.png

So, considering all the factors that go into seasonal forecasting, the ECMWF is a much more reliable long-range model than people are giving it credit for. At least that's my humble, evidence-based opinion (as I see the evidence).

I am not saying that in 2008 & 2010 it did not do a great job for the Atlantic, the past couple of years it has been more wrong than right is my argument, during its May forecast it forecasted mostly above average MSLPs for the tropical Atlantic into the GOM with well below average ACE.

[LarryWx]

Larry You can find it in the link below. Goes back to 2008.

EUROSIP

Thanks. That's nice to be able to see. So, I took a careful look at these Euro ASO SLP forecasts going back to 2008 and learned a lot. Here's what I found regarding past Euro ASO SLP forecasts made in May (June in 2008):

1. The 2018 May forecast is the 2nd least active forecast since 2008 with only 2009 barely less active overall (and even that's debatable). It is a much less active forecast than 2017's, which was actually pretty much neutral in the Car./GOM.

2. I compared these May forecasts with actual ASO TC activity and here are my grades:

2017: D (worst of any); forecast was neutral GOM/Car./slightly quieter than normal elsewhere except more solidly quieter than normal E to S MDR
2016: B; overall pretty neutral forecast W MDR/GOM/subtropics but inactive E MDR
2015: B; forecast pretty inactive tropics but near normal subtropics
2014: A; forecast inactive tropics but near normal subtropics; 2nd least active of any back to 2008 excluding 2018
2013: C; forecast pretty neutral everywhere
2012: C; forecast pretty inactive most of MDR/GOM but neutral much of subtropics E of 60W
2011: B; forecast pretty active most of MDR/GOM/subtropics west of 60W, especially E MDR, but neutral subtropics E of 60W
2010: A; forecast was the most active of any back to 2008
2009: B; forecast was the least active of any back to 2008
2008: A; forecast was 2nd most active of any back to 2008, including more active N MDR vs S MDR

Average grade B: pretty good and worthy of being followed even though 3 of 10 got a C or D
----------------------------------------------------------------------------------------------------------------------------

May forecasts in order of least active to most active/later ENSO peak/grade


2009: strong Nino/B
2018: ?/?
2014: weak Nino/A
2015: strong Nino/B

2012: warm neutral/C
2016: weak Nina/B
2017: moderate Nina/D
2013: cold neutral/C

2011: moderate Nina/B
2008: weak Nina/A
2010: strong Nina/A

Observations:
- predicted ENSO as of May a big influence on forecast
- performance better overall when forecast near one extreme or the other; note best grades in top and bottom and worst in middle

Conclusion:
With 2018 having the 2nd most inactive forecast since 2008 and considering how the Euro has done in May when near forecast extremes, this May Euro ASO SLP forecast should be taken seriously as far as the chances for a relatively inactive season are concerned even if we get only a weak Nino that shows up late like in 2014.

Larry, one thing I want to point out is that the EUROSIP is a multi model blend used between the Euro, UKMET, NCEP & JMA.
A lot of us refer to the actual ECMWF's forecast which has been most times than not erroneous on MSLPs forecast for the Atlantic.
I would give the ECMWF an "F" on May '17 forecast for ASO, much higher MSLPs than what EUROSIP showed. Unfortunately we can only see going back to 2017 on the ECMWF.

Thanks for that info as I didn't realize that. That means my analysis above has to have two modifications: change the word "Euro" to "EUROSIP" and wait for the EUROSIP May, 2018 ASO forecast to be released to see if it is similar to the 2018 Euro since I accidentally mixed apples and oranges in looking at the Euro for 2018 and the EUROSIP for 2017-2008. I'd rather analyze EUROSIP anyway because it is based on a group of models instead of one.
Also, I'm strictly sticking to ASO for forecasts vs verifications. I'm not looking at JAS.

[LarryWx]

In looking at EUROSIP for 2005-17, I've just figured out that its forecast put out each May for Nino 3.4 SST anomalies during the heart of the hurricane season, ASO, has a significant warm bias. I plan to post about this in detail as soon as I get a chance.

[NotSparta]

In looking at EUROSIP for 2005-17, I've just figured out that its forecast put out each May for Nino 3.4 SST anomalies during the heart of the hurricane season, ASO, has a significant warm bias. I plan to post about this in detail as soon as I get a chance.

That's the problem I have with it this year. Since warm neutral is most likely for ASO, its warm bias will push it into El Niño, causing erroneously high pressures.

[NDG]

In looking at EUROSIP for 2005-17, I've just figured out that its forecast put out each May for Nino 3.4 SST anomalies during the heart of the hurricane season, ASO, has a significant warm bias. I plan to post about this in detail as soon as I get a chance.

That's the problem I have with it this year. Since warm neutral is most likely for ASO, its warm bias will push it into El Niño, causing erroneously high pressures.

Absolutely, by it being very warm biased with its ENSO forecast the last couple of years is the reason for its high MSLPs forecast for the Atlantic, it could be the same reason why for this year if we end up with just a warm neutral ASO, especially if it is central base..