When will the multi-decade active era that began in 1995 end?

[Ntxw]

:uarrow:

I agree, it's completely due to the atmosphere. It can all be explained by mostly atmospheric processes, which is not how an era of -AMO starts. The cool MDR is due to the strong trades induced by +NAO. The subtropical warm pool is due to high pressure, like the EPAC "warm blob" in 2014. The cold pool in the far NATL is due to both the persistent +NAO and the persistent Baffin Bay trough, that being caused by the weakening of the polar vortex. The Baffin BAY trough is also helping to keep +NAO around

How much longer do you think this +NAO will last? If you do see it lasting through the peak of the season, do you think it could pose a problem with tropical systems getting blocked from recurving and posing more of a threat to the SE coast?

It is hard to say. When a signature SSTa pattern is created, feedback from it becomes difficult to change unless something larger displaces it. A period of -NAO won't reverse it, you need months of net -NAO to reverse. Atmospheric patterns come and go but SSTa patterns are harder to change longterm.

[NotSparta]

:uarrow:

I agree, it's completely due to the atmosphere. It can all be explained by mostly atmospheric processes, which is not how an era of -AMO starts. The cool MDR is due to the strong trades induced by +NAO. The subtropical warm pool is due to high pressure, like the EPAC "warm blob" in 2014. The cold pool in the far NATL is due to both the persistent +NAO and the persistent Baffin Bay trough, that being caused by the weakening of the polar vortex. The Baffin BAY trough is also helping to keep +NAO around

How much longer do you think this +NAO will last? If you do see it lasting through the peak of the season, do you think it could pose a problem with tropical systems getting blocked from recurving and posing more of a threat to the SE coast?

It is hard to say. When a signature SSTa pattern is created, feedback from it becomes difficult to change unless something larger displaces it. A period of -NAO won't reverse it, you need months of net -NAO to reverse. Atmospheric patterns come and go but SSTa patterns are harder to change longterm.

Just like the winter reversal, took a couple months of that +NAO to get rid of the record warm MDR SSTs. The only way it could reverse within a month is with a record -NAO, like in March. However, it only lasted a couple of weeks and never reversed the pattern fully

[cycloneye]

The active period from 1995 ended more early than expected or not? This is an important question that requires plenty of analysis and discussions as things have not been too favorable in the North Atlantic (Especially in MDR) in the past few seasons after an active 2010. So pro mets and amateours come and let's discuss about this important topic.

The above quote is the first post of this thread.Thanks to all who have posted discussions about this very important topic question in the past 4 years as it has been very interesting and at the same time have revealed some things that many peeps dont know about all the factors involved in all of this. Let's keep it going folks as things are unclear in 2018 about this question.

[StruThiO]

 https://twitter.com/philklotzbach/status/999400216649347073




 https://twitter.com/philklotzbach/status/999401077702180865




only time the Atlantic has been colder was during the cold AMO regime

[cycloneye]

So let's bump this thread as there may be some signs that point to the 1995 active era ending in 2018. Keep the discussion going.

[NotSparta]

We probably won't be able to tell by this yr alone, given 2017.

[JPmia]

I thought the general consensus based on this discussion the last few years was that by the mid 2020s it would end.

[TheStormExpert]

Wasn’t it expected to last only about 20 years? If that’s the case then it likely ended.

[TheStormExpert]

We probably won't be able to tell by this yr alone, given 2017.

Even if the active era ended you still get active years like 2017 in the mix. But yeah we’ll need another few years to fully determine if it’s over or not. I’d say by 2020 we will know for sure.

[CyclonicFury]

We probably won't be able to tell by this yr alone, given 2017.

Even if the active era ended you still get active years like 2017 in the mix. But yeah we’ll need another few years to fully determine if it’s over or not. I’d say by 2020 we will know for sure.

I agree that it's still soon to tell if the active era is over - especially with the hyperactive 2017 season. If we see a few consecutive below average seasons including a non El Niño year, that would be a stronger indication that the active era is over. It will be interesting to see how long the current -AMO pattern - if it reverses this winter like some models are showing, then 2018 may just be a blip in the active era. To be honest, I feel like this sudden MDR SSTA drop (the one over the last two days) is likely just a temporary fluctuation and I wouldn't be surprised to see it warm back up quite a bit over the next week or two (but probably not to above average levels).

[HurricaneEnzo]

Why is everyone pushing this inactive phase so hard? I guess it depends on your personal criteria but with the exception of 2014 we haven't really seen much of a loss of activity in recent years. A couple of years 1 or 2 storms below average and 2016 and 2017 above average. Yes 2013 was an exceptionally weak year but still produced 14 storms. What exactly are we using to qualify 'inactive'? I don't buy into this whole active or inactive phase anyway. No 2 seasons are the same.

[CyclonicFury]

Why is everyone pushing this inactive phase so hard? I guess it depends on your personal criteria but with the exception of 2014 we haven't really seen much of a loss of activity in recent years. A couple of years 1 or 2 storms below average and 2016 and 2017 above average. Yes 2013 was an exceptionally weak year but still produced 14 storms. What exactly are we using to qualify 'inactive'? I don't buy into this whole active or inactive phase anyway. No 2 seasons are the same.

Probably this talk is going on because of the current -AMO SSTA profile, which is generally associated with inactive seasons. However, after last year, I would caution against declaring the active phase over.

[AnnularCane]

Doesn't the active phase usually last about 30-40 years? I can't quite remember where I read that, but it might have been on here.

[CyclonicFury]

Doesn't the active phase usually last about 30-40 years? I can't quite remember where I read that, but it might have been on here.

The last +AMO phase lasted quite a bit longer, from the 1920s to the 1960s. If the active era ended in 2012 (which I don't think so considering 2016/2017 were quite active, especially the latter), that would be significantly shorter than the last +AMO era. In my opinion, this is something we will not have an answer for a while, though I am leaning to the idea that 2018 is just a blip in a +AMO era.

[Emmett_Brown]

This year certainly will be interesting. Probably some of the coolest ATL MDR temps since the latest active era started in '95. If we still end up having an above average season even with the cool MDR, then there will be some interesting research papers coming up I'm sure.

[Hammy]

Given how active 2016 and 17 were, combined with 2015 being one of the highest ACE-producing Nino years in quite awhile (in addition to so many MDR storms despite the Super Nino) I'd say no

[NDG]

First time posting on this thread, based on previous +AMO they have lasted 30-40 years with a cold AMO years in the mix, so I say no the active era is not over yet, I say at least another 10 years or so, IMO.

[CyclonicFury]

Doesn't look like it with what we are seeing right now.

[NotSparta]

Doesn't look like it with what we are seeing right now.

Yeah, most of the activity has been in the deep tropics, sure doesn't seem like a -AMO year

[Shell Mound]

Doesn't look like it with what we are seeing right now.

Yeah, most of the activity has been in the deep tropics, sure doesn't seem like a -AMO year

Impressively, four of the five hurricanes in 2018 have reached hurricane status in the MDR: Beryl, Florence, Helene, and Isaac.