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

[StruThiO]

Yeah lol Lotta people probably spoiled after last year.. just cause we wont have 3 cat 5s in the mdr this year doesn't mean the season will be a flop

[Alyono]

Yeah lol Lotta people probably spoiled after last year.. just cause we wont have 3 cat 5s in the mdr this year doesn't mean the season will be a flop

yep, after last season, an average year around 15/8/4, similar to 2016, will seem like a quiet season

[Kazmit]

Remember- last preseason many of us were writing off the season and look what happened. We can't say yet whether or not this season will be inactive.

[NotSparta]

Even though there is a -AMO horseshoe (assuming this feature stays for hurricane season, has not been the trend lately), that does not mean -AMO inactivity. 2015's MDR was cool at this point (along with an El Nino), and as Alyono said, it was more active than would have been expected.

One of the factors for that inactivity was Sahel dryness, meaning less tropical waves. When there are less of those in an already hostile environment, it'll be pretty quiet. However, the Sahel appears that it will be rainier than normal this summer, meaning more tropical waves and more chances for TC development and activity.

[SFLcane]

Forget the sst's in april folks...Alyono care to take snab at were steering might setup this season? Hopefully 57 will provide some insight in time.

[Alyono]

Forget the sst's in april folks...Alyono care to take snab at were steering might setup this season? Hopefully 57 will provide some insight in time.

I'd keep watch on the SE USA. May be troughing over the eastern USA. Where that troughing is will be key to determining where the storms could go

[TheStormExpert]

The negative talk towards a active Atlantic Hurricane Season has commenced with Phil K. I’d expect his next seasonal forecast update later this month to go downwards. My guess is a below average season.

https://twitter.com/philklotzbach/status/991775678767886336?s=21

https://twitter.com/philklotzbach/status/992132159543525376?s=21

[LarryWx]

The negative talk towards a active Atlantic Hurricane Season has commenced with Phil K. I’d expect his next seasonal forecast update later this month to go downwards. My guess is a below average season.

https://twitter.com/philklotzbach/status/991775678767886336?s=21

https://twitter.com/philklotzbach/status/992132159543525376?s=21

To me and I'm sure to many who have been affected by prior hurricanes, that would be a major positive. Bring on the quiet season!

[TheStormExpert]

It’s also likely that too many (including I) are focusing too much on the current state of the Atlantic SST’s when come peak season they’re always warm enough to support a TC of some sort. Yes I know warmer than average SST’s in the Subtropical Atlantic and cooler than average SST’s in the Tropical Atlantic usually allows for the Subtropical Atlantic to rob the Tropical Atlantic of it’s energy but if you look at the big picture you have a swath of warmer than average SST’s extending from the NW Caribbean northeast off through the Bahamas and into the North-Central Atlantic. Could this be the spot where waves that struggle but survive the track across quickly spin up and become home brew threats?

[CrazyC83]

highly likely there will be a decent number of named storms and canes. Remember, for as hostile as 2014 and 2015 were, there were still 6 hurricanes in 2014 and 11 named storms, plus a near cat 5 in 2015

This year does not look to be anywhere near as hostile as those two years

The subtropical Atlantic was reasonably favorable in 2014-15. The challenge was getting the systems in position to develop since the MDR was very hostile. I believe those years combined had two hurricanes in the MDR (Gonzalo and Danny), and Gonzalo didn't get going until clear of the islands, while Danny fizzled before the islands.

Meanwhile, the subtropical Atlantic had 8 hurricanes and 3 majors (the other hurricane, Fred, was an oddity in itself).

[Alyono]

highly likely there will be a decent number of named storms and canes. Remember, for as hostile as 2014 and 2015 were, there were still 6 hurricanes in 2014 and 11 named storms, plus a near cat 5 in 2015

This year does not look to be anywhere near as hostile as those two years

The subtropical Atlantic was reasonably favorable in 2014-15. The challenge was getting the systems in position to develop since the MDR was very hostile. I believe those years combined had two hurricanes in the MDR (Gonzalo and Danny), and Gonzalo didn't get going until clear of the islands, while Danny fizzled before the islands.

Meanwhile, the subtropical Atlantic had 8 hurricanes and 3 majors (the other hurricane, Fred, was an oddity in itself).

Hurricane Fred struck the Cape Verde Islands.

Until 2017, 2015 may have been the most favorable MDR season since 2010. It's just that development mainly occurred east of 40W

Gonzalo got going right away. Was a 75kt cane into the islands

[Shell Mound]

Personally, I think that Eric Webb has made a very data-heavy case for a below-average season. His tweets offer a lot of meteorological evidence to support less-than-average activity, even if ENSO were somehow to remain neutral. The warm EPAC (+PMM) north of the equator, plus the -AMO signature in the Atlantic, is convincing in light of the past historical cases that he provides. Nevertheless, a below-average season is not a reason to let one's guard down. While the odds of a major hurricane landfall decrease during a below-average season (and even more so during El Niño), this is partly because about three-fourths of the major hurricanes to hit the U.S. have originated in the MDR, based on records back to 1851. That still leaves a fourth consisting of "non-traditional"/homegrown cases in the subtropics, including the Gulf of Mexico. We could very well see a system like Alicia (1983), Diana (1984), or Bob (1991) in 2018, as these systems developed in the Gulf or along the East Coast, and conditions in 2018 are likely to be relatively more favourable in those areas than in the Caribbean and MDR. So watch out!

[StruThiO]

His tweets are always fascinating to read. I definitely respect his work. I think he definitely is onto something about a below average hurricane season. But I may be biased because I'm rooting for a below average season myself,

[Shell Mound]

 https://twitter.com/MJVentrice/status/992069626963156992



This would indicate more anticyclonic wave-breaking events, hence a persistent TUTT (imparting increased vertical wind shear over the deep tropics), and also allow storms that do form to curve out to sea. In other words, we would be returning to the pattern that has mostly prevailed since 2008, excepting 2017, which featured reduced vertical wind shear and enhanced ridging along the Eastern Seaboard. So not only could we see reduced overall activity, but also a mean trough and out-to-sea tendency.
 https://twitter.com/philklotzbach/status/992132159543525376



Dr. Klotzbach mentions a cold North Atlantic as a contributor to the cool MDR, implying that other factors besides the +NAO (enhanced low-level subtropical ridging and trades) are at work. This means the AMO itself has also trended downward due to North Atlantic Deep Water (NADW) and a weak Atlantic Thermohaline Circulation (THC). This could be a further indicator that the +AMO spike in 2017 was just related to the aftereffects (heat transfer) from the strong El Niño of 2015-16.
 https://twitter.com/webberweather/status/992060054785413121



 https://twitter.com/webberweather/status/992036627282382850



 https://twitter.com/webberweather/status/992037572972023810



 https://twitter.com/webberweather/status/992040066909442050



 https://twitter.com/DanVimont/status/992007772878274561



 https://twitter.com/pppapin/status/991001711287422977



 https://twitter.com/pppapin/status/991009319486275584

[LarryWx]

:uarrow: His tweets are always fascinating to read. I definitely respect his work. I think he definitely is onto something about a below average hurricane season. But I may be biased because I'm rooting for a below average season myself,

Although I sometimes have trouble following him, I have an enormous amount of respect for Eric Webb's knowledge, opinions, and intelligence. I'm familiar with him because he posts frequently at another BB that I'm also a member of. When he talks, I listen. Last year at about this time and into early summer, he was cautioning myself and others that the chance for El Nino wasn't as high as it appeared. This year he has a very different tone as regards a potential Nino at least as of now.

[CyclonicFury]

I honestly think Phil K's AMO index is a bit too weighted to far North Atlantic SSTAs and not enough to MDR SSTAs. At peak season 2014 had a higher AMO index than 2017 based on the CSU data, yet 2017 had over twice as many named storms, and over three times as much ACE. The official AMO values from NOAA have remained consistently positive for the most part (with the exception a few small negative dips in 2014 and 2015). Until we see another non-El Niño season with a -AMO look at peak season and lackluster Atlantic activity, I continue to think we are still in the active phase of Atlantic hurricane activity. Remember 2016 was fairly active too - it’s not just about the MDR.

[NotSparta]

I honestly think Phil K's AMO index is a bit too weighted to far North Atlantic SSTAs and not enough to MDR SSTAs. At peak season 2014 had a higher AMO index than 2017 based on the CSU data, yet 2017 had over twice as many named storms, and over three times as much ACE. The official AMO values from NOAA have remained consistently positive for the most part (with the exception a few small negative dips in 2014 and 2015). Until we see another non-El Niño season with a -AMO look at peak season and lackluster Atlantic activity, I continue to think we are still in the active phase of Atlantic hurricane activity. Remember 2016 was fairly active too - it’s not just about the MDR.

imo, I'd wait two, because even one year could be a fluke, like if there had been a -AMO in 2013. Once two years have passed and the same thing has happened, it would be safe to say we have transitioned

[CyclonicFury]

I honestly think Phil K's AMO index is a bit too weighted to far North Atlantic SSTAs and not enough to MDR SSTAs. At peak season 2014 had a higher AMO index than 2017 based on the CSU data, yet 2017 had over twice as many named storms, and over three times as much ACE. The official AMO values from NOAA have remained consistently positive for the most part (with the exception a few small negative dips in 2014 and 2015). Until we see another non-El Niño season with a -AMO look at peak season and lackluster Atlantic activity, I continue to think we are still in the active phase of Atlantic hurricane activity. Remember 2016 was fairly active too - it’s not just about the MDR.

imo, I'd wait two, because even one year could be a fluke, like if there had been a -AMO in 2013. Once two years have passed and the same thing has happened, it would be safe to say we have transitioned

Agree. I just think it is way too early to think that the AMO has transitioned into the cold phase. As recently as January, the MDR was very warm still. If it persists like this for a year without the MDR ever going above average, then a flip may have occurred. IMO, a three month stretch of a generally positive NAO is not enough evidence that the cold phase of the AMO is here to stay - it could easily flip back negative this summer and fall.

[NotSparta]

I honestly think Phil K's AMO index is a bit too weighted to far North Atlantic SSTAs and not enough to MDR SSTAs. At peak season 2014 had a higher AMO index than 2017 based on the CSU data, yet 2017 had over twice as many named storms, and over three times as much ACE. The official AMO values from NOAA have remained consistently positive for the most part (with the exception a few small negative dips in 2014 and 2015). Until we see another non-El Niño season with a -AMO look at peak season and lackluster Atlantic activity, I continue to think we are still in the active phase of Atlantic hurricane activity. Remember 2016 was fairly active too - it’s not just about the MDR.

imo, I'd wait two, because even one year could be a fluke, like if there had been a -AMO in 2013. Once two years have passed and the same thing has happened, it would be safe to say we have transitioned

Agree. I just think it is way too early to think that the AMO has transitioned into the cold phase. As recently as January, the MDR was very warm still. If it persists like this for a year without the MDR ever going above average, then a flip may have occurred. IMO, a three month stretch of a generally positive NAO is not enough evidence that the cold phase of the AMO is here to stay - it could easily flip back negative this summer and fall.

The root causes of a -AMO and this signature are also different too. -AMO usually means slower AMOC, which ends up causing cooler SSTs, and more +NAO as a byproduct. This signature was caused by +NAO and AWB. Completely different, and evidence that this is more of a temporary, atmospherically driven phenomenon.

[Ntxw]

The AMO is a fickle thing. There isn't a huge consensus if the previous warm phase ended, started, moved, whichever way you want to point at. If you're looking decades then it's been fairly warm overall. The ebb and flow year to year can be atmospherically driven as stated above (AMOC). Plus warming trends of global SSTs also muddies the picture. Often times causing the pressures and oceanic temps not to cooperate.