2021 Indicators: SST's / SAL / MSLP / Shear / Steering / Instability / Sat Images

[Hypercane_Kyle]

Yeah it's definitely a hypothesis that is floated around. I've heard various thoughts on how the Atlantic Nino could be constructive or destructive for a busy MDR season, but one thing I personally think is highly likely with this kind of pattern is it would create a strong gradient between the north with a lot of dry air but the south with very wet conditions that could allow more storms that originate almost near the equator to form. While we have yet to see what happens, I also think that we may see more storms hit countries like Trinidad, Guyana, Venezuela, or Colombia with this.

Additionally, while I am only speculating as of now, I do think there may be a possibility that this sort of pattern may allow for the return of a dreaded threat we have not seen since the 2000s: Caribbean cruisers.

In all fairness 2020 had at least a couple Caribbean cruisers. I remember hearing about an Atlantic Nino last year but it was pretty transient.

Oh yes you're right, but maybe I should have clarified my previous comment when I said "Caribbean cruiser," I am referring to the storms that originate in the MDR or near the Cape Verde Islands and then go on to become very powerful in the Caribbean Sea

Yeah, storms like Dean, Felix, Allen, Emily, Ivan, et cetera. It's definitely been a long time since we've seen a powerful hurricane take that path.

[Ubuntwo]

Yeah it's definitely a hypothesis that is floated around. I've heard various thoughts on how the Atlantic Nino could be constructive or destructive for a busy MDR season, but one thing I personally think is highly likely with this kind of pattern is it would create a strong gradient between the north with a lot of dry air but the south with very wet conditions that could allow more storms that originate almost near the equator to form. While we have yet to see what happens, I also think that we may see more storms hit countries like Trinidad, Guyana, Venezuela, or Colombia with this.

Additionally, while I am only speculating as of now, I do think there may be a possibility that this sort of pattern may allow for the return of a dreaded threat we have not seen since the 2000s: Caribbean cruisers.

In all fairness 2020 had at least a couple Caribbean cruisers. I remember hearing about an Atlantic Nino last year but it was pretty transient.

Oh yes you're right, but maybe I should have clarified my previous comment when I said "Caribbean cruiser," I am referring to the storms that originate in the MDR or near the Cape Verde Islands and then go on to become very powerful in the Caribbean Sea

True, in 2020 most waves delayed development until they were already within the Caribbean. The last majors to do so were in 2007. It does seem like this year could have the MDR profile to facilitate storms of that nature.

[aspen]

In all fairness 2020 had at least a couple Caribbean cruisers. I remember hearing about an Atlantic Nino last year but it was pretty transient.

Oh yes you're right, but maybe I should have clarified my previous comment when I said "Caribbean cruiser," I am referring to the storms that originate in the MDR or near the Cape Verde Islands and then go on to become very powerful in the Caribbean Sea

True, in 2020 most waves delayed development until they were already within the Caribbean. The last majors to do so were in 2007. It does seem like this year could have the MDR profile to facilitate storms of that nature.

Even good MDR years had trouble creating a true Caribbean Cruiser. They either turned away before reaching the WCar (Matthew ‘16 and Maria ‘17), or they didn’t develop until the middle of the Caribbean (Eta and Iota ‘20). I don’t know and personally doubt that this year will manage to finally pull off a true Caribbean cruiser, because both 2017 and 2020 could have done so but failed, and they definitely had more favorable-looking MDRs by this time than 2021 has.

[Ubuntwo]

Oh yes you're right, but maybe I should have clarified my previous comment when I said "Caribbean cruiser," I am referring to the storms that originate in the MDR or near the Cape Verde Islands and then go on to become very powerful in the Caribbean Sea

True, in 2020 most waves delayed development until they were already within the Caribbean. The last majors to do so were in 2007. It does seem like this year could have the MDR profile to facilitate storms of that nature.

Even good MDR years had trouble creating a true Caribbean Cruiser. They either turned away before reaching the WCar (Matthew ‘16 and Maria ‘17), or they didn’t develop until the middle of the Caribbean (Eta and Iota ‘20). I don’t know and personally doubt that this year will manage to finally pull off a true Caribbean cruiser, because both 2017 and 2020 could have done so but failed, and they definitely had more favorable-looking MDRs by this time than 2021 has.

In a way a super favorable MDR can also inhibit Caribbean cruisers. To keep a storms' latitude low there has to be either very intense ridging across the basin, or storms need to remain somewhat inhibited before reaching the WCarib. That delicate balance is probably why these kinds of systems are so rare. 2020's MDR was just a little too hostile, 2017's a little too favorable.

[Deshaunrob17]

Oh yes you're right, but maybe I should have clarified my previous comment when I said "Caribbean cruiser," I am referring to the storms that originate in the MDR or near the Cape Verde Islands and then go on to become very powerful in the Caribbean Sea

True, in 2020 most waves delayed development until they were already within the Caribbean. The last majors to do so were in 2007. It does seem like this year could have the MDR profile to facilitate storms of that nature.

Even good MDR years had trouble creating a true Caribbean Cruiser. They either turned away before reaching the WCar (Matthew ‘16 and Maria ‘17), or they didn’t develop until the middle of the Caribbean (Eta and Iota ‘20). I don’t know and personally doubt that this year will manage to finally pull off a true Caribbean cruiser, because both 2017 and 2020 could have done so but failed, and they definitely had more favorable-looking MDRs by this time than 2021 has.

Looks like I had the definition of Caribbean Cruiser wrong because wasn't Irma a cruiser? Also can't Mathews be classified as a cruiser since it did became a storm before the islands ?

[IsabelaWeather]

True, in 2020 most waves delayed development until they were already within the Caribbean. The last majors to do so were in 2007. It does seem like this year could have the MDR profile to facilitate storms of that nature.

Even good MDR years had trouble creating a true Caribbean Cruiser. They either turned away before reaching the WCar (Matthew ‘16 and Maria ‘17), or they didn’t develop until the middle of the Caribbean (Eta and Iota ‘20). I don’t know and personally doubt that this year will manage to finally pull off a true Caribbean cruiser, because both 2017 and 2020 could have done so but failed, and they definitely had more favorable-looking MDRs by this time than 2021 has.

Looks like I had the definition of Caribbean Cruiser wrong because wasn't Irma a cruiser? Also can't Mathews be classified as a cruiser since it did became a storm before the islands ?

No, Irma went north of PR. A Caribbean cruiser is a storm that stays south of the GA's

[Shell Mound]

 https://twitter.com/webberweather/status/1407725137030389760



 https://twitter.com/cyclonicwx/status/1407725842055237632



 https://twitter.com/DCAreaWx/status/1407734776900079617



 https://twitter.com/webberweather/status/1407737951186939908



 https://twitter.com/cyclonicwx/status/1407739509748424710



 https://twitter.com/DerekOrtt/status/1407772393192542210



 https://twitter.com/yconsor/status/1407741168167833608

[cycloneye]

 https://twitter.com/BenNollWeather/status/1408064870625521664

[BYG Jacob]

Looks like we're in for a very long and dangerous year again.

[aspen]

The fact that we’ve had back-to-back strong tropical waves that had or have a chance of development — one of which was close to being a brief TD — in late June is really saying something. If the African Standing Wave and WAM remain favorable, ASO is going to be hectic.

[cycloneye]

I can smell those annual season cancel posts comming if this happens.

 https://twitter.com/AnthonyMweather/status/1408219983491047424

[aspen]

I can smell those annual season cancel posts comming if this happens.

https://twitter.com/AnthonyMweather/status/1408219983491047424

Look at the last third of July onwards as the suppressive MJO phase winds down. The MDR becomes favorable again, and the rising branch over Africa/the IO strengthens. By this point, SSTs in the tropical Atlantic should be much higher than they are now, so combining this with the return to a favorable setup along with the still active WAM, we could be in for quite a surprise after 2-3 weeks of slow activity. The setup for early August also looks very favorable, with strong rising motion over the eastern MDR/Africa/IO with sinking air in the East Pacific.

Also, the suppressive MJO phase won’t exclude subtropical systems like Dolly (which also formed in a suppressive MJO), or tropical waves that make it to the Caribbean/Gulf and develop after the MJO recedes from those longitudes.

[SFLcane]

I can smell those annual season cancel posts comming if this happens.

https://twitter.com/AnthonyMweather/status/1408219983491047424

Look at the last third of July onwards as the suppressive MJO phase winds down. The MDR becomes favorable again, and the rising branch over Africa/the IO strengthens. By this point, SSTs in the tropical Atlantic should be much higher than they are now, so combining this with the return to a favorable setup along with the still active WAM, we could be in for quite a surprise after 2-3 weeks of slow activity. The setup for early August also looks very favorable, with strong rising motion over the eastern MDR/Africa/IO with sinking air in the East Pacific.

Also, the suppressive MJO phase won’t exclude subtropical systems like Dolly (which also formed in a suppressive MJO), or tropical waves that make it to the Caribbean/Gulf and develop after the MJO recedes from those longitudes.

When was the last time we got a significant TC in the first two weeks of August though?

[aspen]

I can smell those annual season cancel posts comming if this happens.

https://twitter.com/AnthonyMweather/status/1408219983491047424

Look at the last third of July onwards as the suppressive MJO phase winds down. The MDR becomes favorable again, and the rising branch over Africa/the IO strengthens. By this point, SSTs in the tropical Atlantic should be much higher than they are now, so combining this with the return to a favorable setup along with the still active WAM, we could be in for quite a surprise after 2-3 weeks of slow activity. The setup for early August also looks very favorable, with strong rising motion over the eastern MDR/Africa/IO with sinking air in the East Pacific.

Also, the suppressive MJO phase won’t exclude subtropical systems like Dolly (which also formed in a suppressive MJO), or tropical waves that make it to the Caribbean/Gulf and develop after the MJO recedes from those longitudes.

When was the last time we got a significant TC in the first two weeks of August though?

While only a Cat 1, I would still count Earl ‘16 as a significant early August TC due to its impacts in Central America. It might’ve gotten stronger if it had more time. Franklin ‘17 was also an early August Cat 1 from an AEW that hit a Central American country, and Gert of the same year was almost a Cat 3 in mid August.

Other recent August hurricanes during the first half of the month include Ernesto ‘12 (Cat 2), Bill ‘09 (Cat 4), Dean ‘07 (Cat 5), Irene ‘05 (Cat 2), Alex ‘04 (Cat 3), Charley ‘04 (Cat 4), Erika ‘03 (Cat 1), and Alberto ‘00 (Cat 3). However, only Earl, Ernesto, Alex, and Alberto count as early August systems. There are a good amount of active seasons like 2001 and 2011 that didn’t see their first hurricane until much later.

[cycloneye]

 https://twitter.com/AndyHazelton/status/1408438740310179840

[captainbarbossa19]

https://twitter.com/AndyHazelton/status/1408438740310179840

Even if the MDR does resume cooling, I think it can easily rebound in August and September. We have seen it before. I am sure if it does and SAL becomes dominant in July, there will be many season cancel posts coming. It really seems silly that some people think July should be really active. It sometimes happens, but it is rare. If I could guess, I would say we will have 0-2 storms next month. I know--not really taking a big risk there.

[Shell Mound]

Had SSTs been above average as opposed to slightly below, both 95L and the system east of the Lesser Antilles probably would have been named by now. Clearly the Atlantic Niño is reinforcing the ASW and resulting in fairly vigorous easterly waves. Vertical wind shear has also not been prohibitively strong, and moisture has been decent thus far, so SSTs seem to be the only real limiting factor in regard to this season’s ceiling, albeit a significant one. The key is whether the ongoing warming will continue and result in a more +AMM/+AMO setup come ASO. It needs to occur rather quickly, given that we need to see AEW-related development in the deep tropics during July in order to increase the odds of a hyperactive season.

[aspen]

Had SSTs been above average as opposed to slightly below, both 95L and the system east of the Lesser Antilles probably would have been named by now.

SSTs for the Lesser Antilles tropical wave were perfectly acceptable for development. It just couldn’t compete against normal June MDR shear, yet it got really close to being classified as a TD.

[Shell Mound]

Had SSTs been above average as opposed to slightly below, both 95L and the system east of the Lesser Antilles probably would have been named by now.

SSTs for the Lesser Antilles tropical wave were perfectly acceptable for development. It just couldn’t compete against normal June MDR shear, yet it got really close to being classified as a TD.

Still, SSTs remain well below the required level of a hyperactive season with seasonal ACE ≥ 150. The easternmost MDR is already cooling down as trades resume.

[aspen]

Had SSTs been above average as opposed to slightly below, both 95L and the system east of the Lesser Antilles probably would have been named by now.

SSTs for the Lesser Antilles tropical wave were perfectly acceptable for development. It just couldn’t compete against normal June MDR shear, yet it got really close to being classified as a TD.

Still, SSTs remain well below the required level of a hyperactive season with seasonal ACE ≥ 150. The easternmost MDR is already cooling down as trades resume.

No way SSTs in the MDR are going to be this cool by late July into early August, when the suppressive MJO moves out and the rising branch over Africa strengthens. It shouldn’t be much less than average by then.