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

[SFLcane]

Larry is potentially going to alter the entire Atlantic as it recurves.

[AlphaToOmega]

Even the CFSv2 knows September will be very active

[AlphaToOmega]

So far, none of the inhibiting factors people have discussed have come to fruition. 2021 was not plagued with TUTTs. 2021 does not have a below-average MDR. 2021 never had a negative AMO. The only factor that inhibited 2021 was Saharan dust, but that is a factor every year.

[AlphaToOmega]

Amplified Phase IV for peak season
Again, Phase IV is the most favorable phase of the MJO

[CyclonicFury]

A suppressed KW is expected to cross the Atlantic in a week or so, which may limit new TC formations around that time. After that, we might see a weak CCKW pass the Atlantic again which could lead to another period of activity.

[tolakram]

Shear has been the name of the game so far, perhaps because of the warmer than normal Nino 1+2 and subtropical Atlantic.

I think these two factors will combine to prevent a significant rise in strong activity during climatological the peak of the season. So far the MJO has not helped.

Nope, things changed very soon after the typical beginning of the season, Aug 20th. Now Larry has formed, is moving at 17mph, and developing rapidly. Thus the importance of never thinking current conditions will persist. Works both ways though, just because we've been active doesn't mean we will stay active. What this reinforces for me, though, is how poorly we can predict even a week in advance, much less 2 weeks.

[aspen]

Two years ago today, Dorian became a 160 kt Cat 5 at landfall. It had become the first major a few days prior, so this got me thinking about how 2021 stacks up to other active seasons in terms of when their majors formed and how many they had by the start of September.

2021: First major (Grace) on 8/21, second major (Ida) on 8/29. Larry could be the third major by the end of the week.

2020: Only one major by now (Laura, on 8/26). The second (Teddy) wouldn’t form until 9/17, and the third (Delta) was another 3-ish weeks later

2019: Dorian became the first major on 8/30, and the second (Humberto) wouldn’t become one until 9/18. Lorenzo became the last major on 9/27.

2018: There were no majors before September. Florence became the first on 9/5, and the only other was Michael on 10/9.

2017: Harvey became the first major on 8/25, followed by Irma on 9/1 and Jose on 9/8.

2016: Gaston became the first major on 8/28, but Matthew wouldn’t become the second until 9/30. Nicole wouldn’t become the third for another two weeks.

2011: Irene attained Cat 3 status on 8/24 and was followed by Katia becoming a major on 9/5. Ophelia would become the third major by the end of September.

2010: Danielle and Earl both formed in August and became the first two majors on 8/27 and 9/2, respectively. Igor would follow on Sept 12/13.


If Larry becomes a major, 2021 will be the fastest to three majors since 2005. So far the only seasons that pace similarly are 2010 and 2017.

[psyclone]

Shear has been the name of the game so far, perhaps because of the warmer than normal Nino 1+2 and subtropical Atlantic.

I think these two factors will combine to prevent a significant rise in strong activity during climatological the peak of the season. So far the MJO has not helped.

Nope, things changed very soon after the typical beginning of the season, Aug 20th. Now Larry has formed, is moving at 17mph, and developing rapidly. Thus the importance of never thinking current conditions will persist. Works both ways though, just because we've been active doesn't mean we will stay active. What this reinforces for me, though, is how poorly we can predict even a week in advance, much less 2 weeks.

A typical active season features several bursts of peak season activity interspersed with relative periods of tranquility, the first of which is due in the latter half of August. This year is delivering thus far and right on schedule. Extreme activity (like july 2005) outside of those timeframes is rare, even in active to hyperactive seasons. Larry looks to be a major, a huge ace builder and hopefully a photogenic fish storm.

[AlphaToOmega]

It is peak season now. The bell has rung. SAL is no longer a factor. Dry air is no longer a factor. MJO is no longer a factor. The only factor is the general pattern, and the general pattern supports a hyperactive hurricane season. TUTTs are not a factor this year like they were last year. People who live in the tropics should be ready because it is only bad news from here.

[SFLcane]

It is peak season now. The bell has rung. SAL is no longer a factor. Dry air is no longer a factor. MJO is no longer a factor. The only factor is the general pattern, and the general pattern supports a hyperactive hurricane season. TUTTs are not a factor this year like they were last year. People who live in the tropics should be ready because it is only bad news from here.

Most important thing- big east coast trof preventing any cv waves from coming to far west. But yea I don't buy the quiet either. The GFS is clueless on intraseasonal variability, and the Euro is usually too stingy on MDR cyclogenesis, with some notable exceptions. We'll see another TC or two in the MDR before the 15th.

[Category5Kaiju]

 https://twitter.com/philklotzbach/status/1433040834555887619




Maybe a hyperactive 2021 hurricane season may not be off the table?

[AlphaToOmega]

https://twitter.com/philklotzbach/status/1433040834555887619

Maybe a hyperactive 2021 hurricane season may not be off the table?

A hyperactive season was never off the table. It was always the most likely outcome based on the VP and SST anomaly patterns.

[Teban54]

https://twitter.com/philklotzbach/status/1433040834555887619

Maybe a hyperactive 2021 hurricane season may not be off the table?

Has it ever been off the table actually?

[Category5Kaiju]

https://twitter.com/philklotzbach/status/1433040834555887619

Maybe a hyperactive 2021 hurricane season may not be off the table?

Has it ever been off the table actually?

Oh no it hasn't, but there have been some individuals I have seen on social media who have been very confident and unbudging in saying that this year has no chance of being hyperactive, so that post was just a friendly, fun fact reminder that hyperactivity is still very much on the table.

[aspen]

Larry was assessed as a T4.0 storm with an eye by the manual Dvorak fix, so it'll likely be a hurricane at 5pm, or 11pm at the latest. It could be the first hurricane east of 30W since Danielle in 2004, a hyperactive year with many long-trackers.

[AlphaToOmega]

https://twitter.com/philklotzbach/status/1433040834555887619

Maybe a hyperactive 2021 hurricane season may not be off the table?

Moreover, only one of those seasons experienced activity at a rate comparable to that of 2021. Can anyone guess which one that is?
It does not guarantee a season that will rival 2020 and 2005 in terms of ACE and storm count, but such a possibility cannot be excluded as of now.

[Teban54]

https://i.imgur.com/TyyS6ti.png
Larry was assessed as a T4.0 storm with an eye by the manual Dvorak fix, so it'll likely be a hurricane at 5pm, or 11pm at the latest. It could be the first hurricane east of 30W since Danielle in 2004, a hyperactive year with many long-trackers.

Doesn't that title belong to Fred 2015, the easternmost hurricane in the Atlantic?

[AlphaToOmega]

It is peak season now. The bell has rung. SAL is no longer a factor. Dry air is no longer a factor. MJO is no longer a factor. The only factor is the general pattern, and the general pattern supports a hyperactive hurricane season. TUTTs are not a factor this year like they were last year. People who live in the tropics should be ready because it is only bad news from here.

Most important thing- big east coast trof preventing any cv waves from coming to far west. But yea I don't buy the quiet either. The GFS is clueless on intraseasonal variability, and the Euro is usually too stingy on MDR cyclogenesis, with some notable exceptions. We'll see another TC or two in the MDR before the 15th.

I always thought the Euro was the best model for intraseasonal variation.

[NotSparta]

Larry is potentially going to alter the entire Atlantic as it recurves.

https://i.postimg.cc/zfbmvVK7/DC0-E8-FDB-5-BE1-4-C97-98-FC-5-B21-D2-ECBEC4.jpg

Reminds me recurving WPAC typhoons influencing the downstream flow

[CyclonicFury]

Larry is potentially going to alter the entire Atlantic as it recurves.

https://i.postimg.cc/zfbmvVK7/DC0-E8-FDB-5-BE1-4-C97-98-FC-5-B21-D2-ECBEC4.jpg

Reminds me recurving WPAC typhoons influencing the downstream flow

It seems relatively common to have a brief respite in Atlantic TC activity after a recurving CV hurricane. The Atlantic was quiet for about 10 days after Teddy last year.