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

[cycloneye]

@RyanMaue
The peak of the Hurricane season is still 3-months away (2nd week of September). The waters in the tropical Atlantic will continue to warm for the next few months -- and by August 31, even if slightly cooler than normal, still plenty warm for hurricane development regardless.

[Shell Mound]

 https://twitter.com/webberweather/status/1007676193469026305

Since most of the major hurricanes to hit the mainland U.S. since 1851 have formed in the MDR, increased vertical wind shear (stronger TUTT) + weaker-than-average subtropical ridge = mean TC formation relatively favoured in subtropics vs. deep tropics and much reduced chance of a strong hurricane hitting the mainland U.S. Based on your indices, do you know of any years similar to 2018 that still managed to feature at least one major hurricane landfall in the lower forty-eight states? At some point, I think that models should be constructed to more accurately diagnose seasonal storm risk to different regions of the mainland U.S. and Caribbean, based on a number of dynamical factors. I have always found your tweets to be both highly informative and meteorologically sound (and often quite accurate). Welcome!

[CyclonicFury]

IMO, we should not jump to the conclusion that the current -AMO SST setup is a permenant flip. Last year the MDR was very warm and the overall AMO pattern resembled a positive phase, and that reflected with the Atlantic basin's very high activity. If the -AMO pattern persists into 2019/20 without ever turning positive, that may be a better sign a flip has occurred.

[Eric Webb]

IMO, we should not jump to the conclusion that the current -AMO SST setup is a permenant flip. Last year the MDR was very warm and the overall AMO pattern resembled a positive phase, and that reflected with the Atlantic basin's very high activity. If the -AMO pattern persists into 2019/20 without ever turning positive, that may be a better sign a flip has occurred.

I've heard this same line of rationale over and over again since 2013 (doesn't necessarily mean it's wrong to think this way however). The MDR is the coldest since 1982 this year, and the Atlantic has been consistently colder for the most part since 2013 vs the 1995-2012 period, what we're seeing has been ongoing for several years generally speaking and last year was an exception not the rule. If this oncoming central Pacific El Nino is not able to generate a consistent -NAO (they usually are able to but this doesn't always occur) and is somehow overwhelmed by the background state that's becoming increasingly more hostile to -NAOs as the climate warms (warmer climates favor +NAOs because as the Hadley Cells expand, wave activity flux shifts poleward strengthening the Atlantic jet and Icelandic Vortex, see the medieval climate anomaly), and/or interannual persistence, the -AMO will persist into the following year.

[cycloneye]

@MJVentrice
Seeing indications that July is going to be very quiet regarding tropical development. I may go all the way and say no tropical cyclogenesis over the Atlantic Basin this July.

[Siker]

@MJVentrice
Seeing indications that July is going to be very quite regarding tropical development. I may go all the way and say no tropical cyclogenesis over the Atlantic Basin this July.

Oh man, I just flashed back to his prediction of no hurricanes from September 7th to September 25th last year. Not that conditions look favorable for July, but long range predictions are difficult.

[TheStormExpert]

Only further strengthens my and many others thoughts on not seeing anything until at least the 2nd week of August. July is typically a dead month in the tropics as the Central America Monsoon Gyre focuses more on the Pacific side allowing them to be active and African Easterly Waves are yet to full maturity for tropical development.

[CyclonicFury]

As I have stated before, the best chance for any tropical cyclogenesis in the Atlantic this July will probably be in the subtropical western Atlantic off the U.S. East Coast. It is common in El Niño years to see a weak spinup of non-tropical origin along the Gulf Stream. Examples include Bill 1997, Arthur 2002, Unnamed TS/Beryl 2006, and Claudette 2015. I would say chances we see an Atlantic named storm this July are about 50/50. However, unlike last July, the MDR should be completely dead this July.

[Siker]

As I have stated before, the best chance for any tropical cyclogenesis in the Atlantic this July will probably be in the subtropical western Atlantic off the U.S. East Coast. It is common in El Niño years to see a weak spinup of non-tropical origin along the Gulf Stream. Examples include Bill 1997, Arthur 2002, Unnamed TS/Beryl 2006, and Claudette 2015. I would say chances we see an Atlantic named storm this July are about 50/50. However, unlike last July, the MDR should be completely dead this July.

Also Arthur 2014, though his origins were an MCV over the southeast that moved offshore rather than a decaying front.

[Alyono]

Most here and in the ENSO forum are entirely focused on how the deep tropics will play out

The season will be governed by what happens in the subtropics. Take the last 5 4 el niños

2002: 12 storms. 9 formed in the subtropics or GOM
2014: 15 storms. 6 in subtropics or GOM
2006: 10 storms. 4 in subtropics or GOM
2009: 9 storms. 3 in subtropics or GOM
2015: 11 storms. 6 in subtropics or GOM

MDR (including Caribbean) will be less active than normal most likely. We need to focus on the subtropics and how much genesis we see there. That will determine if the season is above or below normal (or near normal)

[NotSparta]

true, shear has been below average and SSTs are above average in the subtropics, which could make for above average activity there.

[cycloneye]

@philklotzbach
A large portion of the tropical Atlantic is running more than 1.5°C cooler than it was last year at this time. This likely portends a much less active Atlantic #hurricane season than last year.

 https://twitter.com/philklotzbach/status/1009581731886665728

[Kingarabian]

Hate to say it but the proof was in the pudding before the hurricane season ever started... Unfortunately, some institutions who made forecasts for the Atlantic hurricane season have set themselves up for (undeserved of course) scrutiny.

[Alyono]

Hate to say it but the proof was in the pudding before the hurricane season ever started... Unfortunately, some institutions who made forecasts for the Atlantic hurricane season have set themselves up for (undeserved of course) scrutiny.

again, you are focusing too much on the deep tropics

the season will be determined by the subtropics, as it is most seasons

[CyclonicFury]

While the deep tropics should be less active than normal, the subtropics will probably be more active than normal. If a wave survives the hostile tropics, it may have a better chance in the subtropics.

[TropicalAnalystwx13]

Hate to say it but the proof was in the pudding before the hurricane season ever started... Unfortunately, some institutions who made forecasts for the Atlantic hurricane season have set themselves up for (undeserved of course) scrutiny.

again, you are focusing too much on the deep tropics

the season will be determined by the subtropics, as it is most seasons

And the subtropics look favorable.

[Alyono]

subtropics/GOM genesis

1995: 5
1996: 2
1997: 7
1998: 6
1999: 4
2000: 6
2001: 8
2002: 9
2003: 9
2004: 6
2005: 15 (hint... it wasn't the deep tropics that made 2005)
2006: 4
2007: 7
2008: 5
2009: 3
2010: 4 (3 if you dont count Hermine)
2011: 11
2012: 10
2013: 8
2014: 4
2015: 6
2016: 8
2017: 7

you want an active season? The subtropics/GOM had best give it to you, most years

[CyclonicFury]

With the recent high activity in the subtropics, and strong warm anomaly in this region, I would be shocked if we do not see at least one major hurricane form north of 25N.

[Alyono]

Hate to say it but the proof was in the pudding before the hurricane season ever started... Unfortunately, some institutions who made forecasts for the Atlantic hurricane season have set themselves up for (undeserved of course) scrutiny.

again, you are focusing too much on the deep tropics

the season will be determined by the subtropics, as it is most seasons

And the subtropics look favorable.

which is why I went with 18 storms

[TheStormExpert]

Hate to say it but the proof was in the pudding before the hurricane season ever started... Unfortunately, some institutions who made forecasts for the Atlantic hurricane season have set themselves up for (undeserved of course) scrutiny.

again, you are focusing too much on the deep tropics

the season will be determined by the subtropics, as it is most seasons

And the subtropics look favorable.

https://i.imgur.com/EKdfOuC.png

Which is why 1985 may very well be the best analog season right now just by looking at that shear forecast. Little action in the Tropical Atlantic and Caribbean but an active Subtropics especially in the Gulf of Mexico and to a lesser extent off the U.S. East Coast.

https://upload.wikimedia.org/wikipedia/ ... ry_map.png