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

[AlphaToOmega]

When you see the CFSv2 forecasting well-below average MSLP in the MDR, it is probably a sign of a tropical cyclone outbreak. Something similar occurred in late August of 2021; there was forecasted below-average MSLP in the MDR, and six storms developed that month. Six or more storms developing in October is not out of the realm of possibility.

August 2021:


October 2021:

[underthwx]

When you see the CFSv2 forecasting well-below average MSLP in the MDR, it is probably a sign of a tropical cyclone outbreak. Something similar occurred in late August of 2021; there was forecasted below-average MSLP in the MDR, and six storms developed that month. Six or more storms developing in October is not out of the realm of possibility.

August 2021:
https://i.postimg.cc/wxL73Lq1/cfs-avg-mslpa-Norm-Mean-atl-2.png

October 2021:
https://i.postimg.cc/nzxyYWkg/cfs-avg-mslpa-Norm-Mean-atl-2.png

Could a possible outbreak be focused in the Caribbean?....if memory serves me...I watched an update yesterday....that made mention of the Caribbean has in the past seasons....been a breeding ground for development during this time of year....

[Teban54]

 https://twitter.com/philklotzbach/status/1441157339218804736



Wow, given the less than stellar MDR SST profile when the season first started (and the number of season cancel posts because of that), this is certainly not the kind of record I was expecting. The time frame is September 9-23, btw.

It's interesting that both 2005 and 2021 didn't feature any quality CV storms during this time period, which might contribute to 2021 making it to the second place since other years had more upwelling occur. Unlike 2005, 2021 finally saw a storm that makes use of the fuel: Sam.

IMO, this also means a better chance of waves surviving and entering the Caribbean during October. Wouldn't be surprised if we actually see developments in the MDR itself.

[AlphaToOmega]

https://twitter.com/philklotzbach/status/1441157339218804736?s=19
Wow, given the less than stellar MDR SST profile when the season first started (and the number of season cancel posts because of that), this is certainly not the kind of record I was expecting. The time frame is September 9-23, btw.

It's interesting that both 2005 and 2021 didn't feature any quality CV storms during this time period, which might contribute to 2021 making it to the second place since other years had more upwelling occur. Unlike 2005, 2021 finally saw a storm that makes use of the fuel: Sam.

IMO, this also means a better chance of waves surviving and entering the Caribbean during October. Wouldn't be surprised if we actually see developments in the MDR itself.

MDR development in October is not that abnormal. We saw MDR development in late October 2010 with Hurricane Tomas.

[Ubuntwo]

MDR development in October is not that abnormal. We saw MDR development in late October 2010 with Hurricane Tomas.

Right, it often takes until mid October for the MDR to shut down. Several MDR storms have formed in December.

[Woofde]

 https://twitter.com/philklotzbach/status/1441157339218804736



Wow, given the less than stellar MDR SST profile when the season first started (and the number of season cancel posts because of that), this is certainly not the kind of record I was expecting. The time frame is September 9-23, btw.

It's interesting that both 2005 and 2021 didn't feature any quality CV storms during this time period, which might contribute to 2021 making it to the second place since other years had more upwelling occur. Unlike 2005, 2021 finally saw a storm that makes use of the fuel: Sam.

IMO, this also means a better chance of waves surviving and entering the Caribbean during October. Wouldn't be surprised if we actually see developments in the MDR itself.

CRW looks even more favorable. This certainly isn't the SST profile of a season that shuts down early.

[AlphaToOmega]

They all tell the same tale. Currently it is impossible to make a valid argument that thermodynamics will be an inhibiting factor for this hurricane season.

[CyclonicFury]

Looks like 99L will probably be Teresa and the wave behind Sam may also become a tropical storm. That would potentially bring the total of September storms to nine including Larry. I must eat crow, AlphaToOmega was right.

[WiscoWx02]

It is honestly incredible that we are again approaching the end of the list. This was never supposed to happen again after 2005 and here we are. The even more incredible thing to think is that 20-30 years ago, Ana, Bill, Claudette, Danny, Julian, Kate, Mindy, Odette, Peter, Rose would never have been named because of the lack of good satellite imagery. To think we would probably only be at Fred right now if it were 1980

[Ubuntwo]

It is honestly incredible that we are again approaching the end of the list. This was never supposed to happen again after 2005 and here we are. The even more incredible thing to think is that 20-30 years ago, Ana, Bill, Claudette, Danny, Julian, Kate, Mindy, Odette, Peter, Rose would never have been named because of the lack of good satellite imagery. To think we would probably only be at Fred right now if it were 1980

Some of these would definitely go unclassified but not most. Satellite imagery was pretty solid in the 90s and obs were not much more sparse. Push it back to the early 20th century and maybe.

[Stormybajan]

It is honestly incredible that we are again approaching the end of the list. This was never supposed to happen again after 2005 and here we are. The even more incredible thing to think is that 20-30 years ago, Ana, Bill, Claudette, Danny, Julian, Kate, Mindy, Odette, Peter, Rose would never have been named because of the lack of good satellite imagery. To think we would probably only be at Fred right now if it were 1980

Running down the naming list is the easiest part, thats for sure. However to get close to 15 and 14 hurricanes with 7 MAJORS, im not expecting that again lets say...8 years from now.
Would be lying though if I ever imagined using up the entire naming list in BACK TO BACK seasons in a row thats astonishing.

[Category5Kaiju]

I mean, seriously, a round of applause for AlphatoOmega, who was confident in predicting a hyperactive September in terms of NS formation, and we are about to plausibly see Victor before October (while many, myself including, were in doubt about Alpha's predictions, especially during that little mid-month lull).

[gatorcane]

I think active / hyperactive years like last year and this one underscore one important point: we may be able to use indicators to know if a season might be active or not but it is still very difficult to know what land areas could get impacted and to me that is the most critical thing to know. Here in South Florida we have yet another season where there has been little to no significant activity so far (October withstanding) despite all of the activity so it has been uneventful and inactive thankfully.

[ElectricStorm]

It is honestly incredible that we are again approaching the end of the list. This was never supposed to happen again after 2005 and here we are. The even more incredible thing to think is that 20-30 years ago, Ana, Bill, Claudette, Danny, Julian, Kate, Mindy, Odette, Peter, Rose would never have been named because of the lack of good satellite imagery. To think we would probably only be at Fred right now if it were 1980

Running down the naming list is the easiest part, thats for sure. However to get close to 15 and 14 hurricanes with 7 MAJORS, im not expecting that again lets say...8 years from now.
Would be lying though if I ever imagined using up the entire naming list in BACK TO BACK seasons in a row thats astonishing.

Assuming Sam becomes a major as expected, that would put us at 4, which is 2 more than we had last year at this point. While I don't think Oct/Nov (especially Nov) will be as crazy as last year, we would only need 3 more majors to tie the record of 7. Personally I think might see 2 more and end with 6 this year but 7 certainly is still in play.

[Category5Kaiju]

Interestingly, every year since 1995 that had at least 5 majors (with 2008 being the one exception but fell short of the criteria by 10 ACE or so) ended as operationally hyperactive years. Wonder if 2021 will do the same

[AlphaToOmega]

Tropical Storm Teresa has formed in the Atlantic. Eight storms have formed this September (Larry, Mindy, Nicholas, Odette, Peter, Rose, Sam, and Teresa). Larry, Nicholas, and Sam have become hurricanes; and Larry was a major hurricane, and Sam is also likely to be a major hurricane. This shows how powerful climatology is for hurricane seasons.

[Ubuntwo]

Tropical Storm Teresa has formed in the Atlantic. Eight storms have formed this September (Larry, Mindy, Nicholas, Odette, Peter, Rose, Sam, and Teresa). Larry, Nicholas, and Sam have become hurricanes; and Larry was a major hurricane, and Sam is also likely to be a major hurricane. This shows how powerful climatology is for hurricane seasons.

I thought 8+ named storms was unlikely this September, we are now poised to have 8-9. I stand corrected . Thankfully land areas have avoided major impacts from the many storms.

[Stormybajan]

This second half flood of named storms is especially impressive when you see the current MJO background state

[AlphaToOmega]

Tropical Storm Teresa has formed in the Atlantic. Eight storms have formed this September (Larry, Mindy, Nicholas, Odette, Peter, Rose, Sam, and Teresa). Larry, Nicholas, and Sam have become hurricanes; and Larry was a major hurricane, and Sam is also likely to be a major hurricane. This shows how powerful climatology is for hurricane seasons.

I thought 8+ named storms was unlikely this September, we are now poised to have 8-9. I stand corrected . Thankfully land areas have avoided major impacts from the many storms.

You can thank Henri for that. Henri, combined with the train of activity we saw and are seeing, made the NAO negative for September, thus sparing most (aside from Newfoundland) from major land impacts.

Hurricane Henri created a weakness in the Bermuda High. Tropical Storms Kate and Julian took advantage of that and recurved out to sea. Hurricane Larry took advantage of that and spared the CONUS and Caribbean from land impacts by impacting Newfoundland. This flood of activity made the Bermuda High incredibly weak. Weakness persisted into mid-September, which allowed Tropical Storms Odette, Peter, and Rose to recurve out to sea. Hurricane Sam is a wild card right now; for the GFS indicates an out to sea storm, but the ECMWF and CMC indicate a landfalling storm.

[Ubuntwo]

You can thank Henri for that. Henri, combined with the train of activity we saw and are seeing, made the NAO negative for September, thus sparing most (aside from Newfoundland) from major land impacts.

Hurricane Henri created a weakness in the Bermuda High. Tropical Storms Kate and Julian took advantage of that and recurved out to see. Hurricane Larry took advantage of that and spared the CONUS and Caribbean from land impacts by impacting Newfoundland. This flood of activity made the Bermuda High incredibly weak. Weakness persisted into mid-September, which allowed Tropical Storms Odette, Peter, and Rose to recurve out to sea. Hurricane Sam is a wild card right now; for the GFS indicates an out to sea storm, but the ECMWF and CMC indicate a landfalling storm.

Pure luck. Aside from Nicholas, almost no tropical waves made it into the Gulf. Supports the idea that an unfavorable MDR can lead to more land impacts.