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

[AlphaToOmega]

https://i.postimg.cc/g0mn1hLM/EC51003-B-BA3-B-48-AB-933-C-1343-E10-E7-CDE.png
https://i.ibb.co/jvrbBbv/LIhurrimpact-2.png
https://i.ibb.co/tQXKZ6J/LIFLhurrcomp-1.png
https://i.ibb.co/51MdKPL/Ska-rmavbild-2021-07-21-kl-16-28-46.png

If the 2021 Atlantic hurricane season were to be delayed, for the most part, until the last week of August, then the EPS’s H5 composite for September is startlingly similar to that of the years that featured at least one hurricane impact on Long Island, NY, during the month of September. These years include the infamous seasons of 1938, 1944, 1960, and 1985. When blended with the years 1945 and 1949 as well, the composite becomes even more similar to the EPS’s H5 forecast for September. One interesting difference between the two subsets is that 1945 and 1949 featured a stronger +PNA signature than the years that featured a hurricane impact on Long Island, suggesting a PDO closer to positive rather than negative territory, and the EPS’s forecast suggests more of a neutral PDO/PNA, in line with recent trends indicating a rise in the PDO over the past month or so. This kind of setup would suggest the potential for a CV-type long-tracker that impacts much of the U.S. East Coast from South FL northward to the Carolinas and New England, similar to Donna (1960).

What are you using for the storm tracks?

https://coast.noaa.gov/hurricanes/

As an aside, why are you using 2004 and 2017 as analogs for 2021 in some of your previous posts? Do you have any evidence? Those are extreme years.

2004 was a steering analog, and 2017 is an MJO analog. 2017 had a burst of activity in June and a lull in July, just like this year.

[SFLcane]

Looking at long-range GEFS this morning and it actually has a very hostile environment into late August now.

https://i.postimg.cc/zXXBbYnx/7-CDE62-C6-AFE8-4-BB0-814-D-42976-F174-B1-B.jpg

Hmmm i'll comeback to this August 1st, if its still showing this pattern then I guess we are looking at another back loaded season. Since 2012 only 2017 seemed to have a decently active early-ish August which is interesting

https://i.postimg.cc/g0mn1hLM/EC51003-B-BA3-B-48-AB-933-C-1343-E10-E7-CDE.png
https://i.ibb.co/jvrbBbv/LIhurrimpact-2.png
https://i.ibb.co/tQXKZ6J/LIFLhurrcomp-1.png
https://i.ibb.co/51MdKPL/Ska-rmavbild-2021-07-21-kl-16-28-46.png

If the 2021 Atlantic hurricane season were to be delayed, for the most part, until the last week of August, then the EPS’s H5 composite for September is startlingly similar to that of the years that featured at least one hurricane impact on Long Island, NY, during the month of September. These years include the infamous seasons of 1938, 1944, 1960, and 1985. When blended with the years 1945 and 1949 as well, the composite becomes even more similar to the EPS’s H5 forecast for September. One interesting difference between the two subsets is that 1945 and 1949 featured a stronger +PNA signature than the years that featured a hurricane impact on Long Island, suggesting a PDO closer to positive rather than negative territory, and the EPS’s forecast suggests more of a neutral PDO/PNA, in line with recent trends indicating a rise in the PDO over the past month or so. This kind of setup would suggest the potential for a CV-type long-tracker that impacts much of the U.S. East Coast from South FL northward to the Carolinas and New England, similar to Donna (1960).

Not sure what that has to do with a delayed start.

[SFLcane]

Hmmm…

CFS is showing a stronger MJO moving into the Atlantic. It seems the ECM was wrong about the pulse moving into the Atlantic by the end of this month.

Keep in mind the low shear comes *after* the pulse crosses. Give or take around Aug 20th

[AlphaToOmega]

Hmmm…

CFS is showing a stronger MJO moving into the Atlantic. It seems the ECM was wrong about the pulse moving into the Atlantic by the end of this month.

Keep in mind the low shear comes *after* the pulse crosses. Give or take around Aug 20th

https://i.postimg.cc/TPqCVzz1/6-CF99582-C34-D-4-A9-C-814-F-A785-A426486-B.jpg

The lull will last until at most August 11 according to the model. I would say August 20 is too late, assuming the CFSv2 model verifies. Then again, the model has a significant problem with the WAM.

[captainbarbossa19]

I for one think the GEFS is biased. Speaking of the Mdr we are coming along give it a few weeks.

https://i.postimg.cc/vmT3vwTY/EE641453-BE09-49-E2-98-A1-BEE4-CF63-FA67.jpg

That looks like a classic -AMM/-AMO. It barely seems to have changed over the past few months. Models have consistently shown too much warming.

Hopefully the MDR will warm or the waves coming off Africa may not develop until they reach the Caribbean. Temperatures are not too cold for development though. Even CDAS shows many 27C temperatures north of 10 N in the MDR. Systems may just not intensify much until they move further west.

[cycloneye]

The warming continues.

 https://twitter.com/cyclonicwx/status/1417936668863176705




 https://twitter.com/cyclonicwx/status/1417937074368532485

[AlphaToOmega]

Here are some likely hurricane tracks. This is based on 2004 and 2012 being steering analogs.

[captainbarbossa19]

Here are some likely hurricane tracks. This is based on 2004 and 2012 being steering analogs.

These may not be bad analog years either. Look how most of the storms did not develop in the MDR. Perhaps water was cooler these years too?

[Category5Kaiju]

2004's MDR sst anomalies at this point in time were not extremely impressive compared to years like 2005, 2010, or 2020, yet it managed to finish as a season with more than 220 ACE and with a pretty active MDR with Frances and Ivan for example. It just shows you how quickly things can change by peak season.

[AxaltaRacing24]

I for one think the GEFS is biased. Speaking of the Mdr we are coming along give it a few weeks.

https://i.postimg.cc/vmT3vwTY/EE641453-BE09-49-E2-98-A1-BEE4-CF63-FA67.jpg

That looks like a classic -AMM/-AMO. It barely seems to have changed over the past few months. Models have consistently shown too much warming.

It has changed more than you think once you compare these images only a month apart.

 https://twitter.com/grogmanweather1/status/1403153830196432901



 https://twitter.com/cyclonicwx/status/1417936668863176705

[hurricanes1234]

https://ibb.co/tz2ktJZ

Just look at the sheer strength of that MJO pulse as it moves into the Western hemisphere in week 1 and 2 of the forecast. -VP everywhere.

[Stormybajan]

https://ibb.co/tz2ktJZ

Just look at the sheer strength of that MJO pulse as it moves into the Western hemisphere in week 1 and 2 of the forecast. -VP everywhere.

Certainly is a strong signal (for now, as things can change) but if that were to pan out as forecast, the entirety of August should be bombarded with the rising pulse phase of the MJO over the Atlantic . Still doesnt guarantee activity butt.. it does increase the chances especially after August 15th when the bell is rung

[hurricanes1234]

https://ibb.co/tz2ktJZ

Just look at the sheer strength of that MJO pulse as it moves into the Western hemisphere in week 1 and 2 of the forecast. -VP everywhere.

Certainly is a strong signal (for now, as things can change) but if that were to pan out as forecast, the entirety of August should be bombarded with the rising pulse phase of the MJO over the Atlantic . Still doesnt guarantee activity butt.. it does increase the chances especially after August 15th when the bell is rung

Agreed, personally I think the most noticeable effect initially (in the first week or so of August) will hopefully be more favourable conditions for rainfall over the islands. The first and second week of July were really hot, dry and dusty so here's to hoping that the widespread -VP means some much needed rainfall as early as the start of August.

[AxaltaRacing24]

https://ibb.co/tz2ktJZ

Just look at the sheer strength of that MJO pulse as it moves into the Western hemisphere in week 1 and 2 of the forecast. -VP everywhere.

Certainly is a strong signal (for now, as things can change) but if that were to pan out as forecast, the entirety of August should be bombarded with the rising pulse phase of the MJO over the Atlantic . Still doesnt guarantee activity butt.. it does increase the chances especially after August 15th when the bell is rung

I don't feel like this season will have a problem getting going when it's time to. I feel that after August 15th or 20th, there might be a barrage of storms all the way through September.

[Shell Mound]

I for one think the GEFS is biased. Speaking of the Mdr we are coming along give it a few weeks.

https://i.postimg.cc/vmT3vwTY/EE641453-BE09-49-E2-98-A1-BEE4-CF63-FA67.jpg

That looks like a classic -AMM/-AMO. It barely seems to have changed over the past few months. Models have consistently shown too much warming.

Hopefully the MDR will warm or the waves coming off Africa may not develop until they reach the Caribbean. Temperatures are not too cold for development though. Even CDAS shows many 27C temperatures north of 10 N in the MDR. Systems may just not intensify much until they move further west.

A cooler MDR is better for the U.S. in terms of Category-4+ hits. Most (not all, but most) Cat-4+ hits are associated with CV-type systems that develop in the MDR. There have been exceptions such as the 1935 hurricane, Camille, and Michael, but most other Cat-4+ impacts were related to storms that formed in the MDR. Currently the MDR will need to warm much more, especially over its northern half, in order to increase the odds of a hyperactive MDR and thus Cat-4+ hits farther west. There has been some notable warming over the southern MDR and part of the Caribbean over the past month, but not enough...yet.

[SFLcane]

 https://twitter.com/ericblake12/status/1418183722713616384

[aspen]

The current ACE total is so high that it’ll take until August 15th or 16th to match the climatological mean on CSU, assuming no storms form between now and mid-August. That means Atlantic ACE will be either near or above-average if the EPac/TUTT shear the western Atlantic for the next 3 weeks, so when something significant does finally form, the basin will be back on track to be ahead of the norm.

[AlphaToOmega]

https://twitter.com/ericblake12/status/1418183722713616384

I would lean towards the ECMWF. The GEFS has had serious problems with VP anomalies.

[Shell Mound]

The current ACE total is so high that it’ll take until August 15th or 16th to match the climatological mean on CSU, assuming no storms form between now and mid-August. That means Atlantic ACE will be either near or above-average if the EPac/TUTT shear the western Atlantic for the next 3 weeks, so when something significant does finally form, the basin will be back on track to be ahead of the norm.

A lot of Elsa’s ACE was artificially inflated past the islands, given that the NHC tended to give it higher MSW than surface + recon data suggested. (See earlier posts by wxman57 on this.) It was definitely a hurricane over the islands, but I doubt it regained hurricane status in the Gulf, and for much of its time as a “TS” it was either a low-end one or briefly an open wave. Plus, Claudette and Danny were borderline cases at best, and might not have been classified just a decade or so earlier. Therefore, I think actual ACE generation to date has been at least a bit lower than indicated.

[Shell Mound]

https://twitter.com/yconsor/status/1417117743200063489

https://twitter.com/stormchaserjs/status/1417118883463503875

Based on the data, there seems to be an inverse correlation between SST in the western Atlantic and (M)H landfalls on Southeast Florida. Am I correct?

Bump for jconsor