Expert forecasts for 2021 North Atlantic Hurricane Season

[Shell Mound]

TSR released their updated outlook yesterday. 20/9/4, 141 ACE. The link seems to be broken unfortunately. http://tropicalstormrisk.com/

The ACE index seems quite low for such an active year. Also, the number of hurricanes and majors is unremarkable vs. that of most hyperactive years.

[cheezyWXguy]

The total named storms predicted raises an eyebrow, would be something to see back to back seasons produce 20+ named storms. I’m actually a little surprised that hurricanes and major hurricanes aren’t a little higher though. With the Caribbean looking the way it is, especially with those sst anomalies, it seems like anything that makes its way into that area is a threat

[Shell Mound]

The CSU forecast now perfectly matches the TSR forecast.

From p. 33 of CSU’s outlook:

Up until now the thirty-day-averaged shear has been running much higher than it typically does during an above-average season. No one has mentioned this yet.

[psyclone]

Above average shear at this point certainly hasn't been prohibitive and looking at the trendline it looks to be a non issue soon if we extrapolate a few weeks. How did that graph look a year ago or in other active seasons like 2017? Considering June and July tend to be pretty quiet, I'm not sure it matters much unless it persists into deep season (mid august and beyond) when we're entitled to the meat and potatoes of the season..

[CyclonicFury]

TSR released their updated outlook yesterday. 20/9/4, 141 ACE. The link seems to be broken unfortunately. http://tropicalstormrisk.com/

The ACE index seems quite low for such an active year. Also, the number of hurricanes and majors is unremarkable vs. that of most hyperactive years.

TSR has been consistently too low with ACE the past several years, as aspen noted yesterday. Even in 2017, they predicted only 17-7-3 with 116 ACE. TSR has underestimated the total ACE every year since 2016.

[SFLcane]

The CSU forecast now perfectly matches the TSR forecast.

From p. 33 of CSU’s outlook:
https://i.postimg.cc/jdSgYZCs/Ska-rmavbild-2021-07-08-kl-19-54-06.png
Up until now the thirty-day-averaged shear has been running much higher than it typically does during an above-average season. No one has mentioned this yet.

Sure, you can thank unfavorable MJO for that.

[aspen]

The CSU forecast now perfectly matches the TSR forecast.

From p. 33 of CSU’s outlook:
https://i.postimg.cc/jdSgYZCs/Ska-rmavbild-2021-07-08-kl-19-54-06.png
Up until now the thirty-day-averaged shear has been running much higher than it typically does during an above-average season. No one has mentioned this yet.

It is going down though, and not every active season has to follow those graphs exactly. They’re averages for a reason.

[OuterBanker]

Very interesting statement from latest CSU outlook.

7 Hurricane Elsa
In general, early season Atlantic hurricane activity has very little correlation with
overall Atlantic hurricane activity. However, when this activity occurs in the tropics
(south of 23.5°N), that is typically a harbinger of a very active season. Hurricane Elsa
formed in the tropical Atlantic and then tracked into the eastern Caribbean (10-20°N, 75-
60°W) at hurricane strength. Since 1900, only six other years have had eastern Caribbean
hurricanes prior to 1 August: 1926, 1933, 1961, 1996, 2005 and 2020. All six of those
years were classified as hyperactive Atlantic hurricane seasons using the NOAA Atlantic
hurricane season definition (>=160 ACE).

[SFLcane]

Very interesting statement from latest CSU outlook.

7 Hurricane Elsa
In general, early season Atlantic hurricane activity has very little correlation with
overall Atlantic hurricane activity. However, when this activity occurs in the tropics
(south of 23.5°N), that is typically a harbinger of a very active season. Hurricane Elsa
formed in the tropical Atlantic and then tracked into the eastern Caribbean (10-20°N, 75-
60°W) at hurricane strength. Since 1900, only six other years have had eastern Caribbean
hurricanes prior to 1 August: 1926, 1933, 1961, 1996, 2005 and 2020. All six of those
years were classified as hyperactive Atlantic hurricane seasons using the NOAA Atlantic
hurricane season definition (>=160 ACE).

[weeniepatrol]

Buckle up folks

[aspen]

Very interesting statement from latest CSU outlook.

7 Hurricane Elsa
In general, early season Atlantic hurricane activity has very little correlation with
overall Atlantic hurricane activity. However, when this activity occurs in the tropics
(south of 23.5°N), that is typically a harbinger of a very active season. Hurricane Elsa
formed in the tropical Atlantic and then tracked into the eastern Caribbean (10-20°N, 75-
60°W) at hurricane strength. Since 1900, only six other years have had eastern Caribbean
hurricanes prior to 1 August: 1926, 1933, 1961, 1996, 2005 and 2020. All six of those
years were classified as hyperactive Atlantic hurricane seasons using the NOAA Atlantic
hurricane season definition (>=160 ACE).

Oh, so 2021 falls into a rare club where the six other seasons average out to 215 ACE, and 4 of them are among the ten most active Atlantic seasons on record in terms of ACE. No that isn’t concerning at all.

[AlphaToOmega]

Very interesting statement from latest CSU outlook.

7 Hurricane Elsa
In general, early season Atlantic hurricane activity has very little correlation with
overall Atlantic hurricane activity. However, when this activity occurs in the tropics
(south of 23.5°N), that is typically a harbinger of a very active season. Hurricane Elsa
formed in the tropical Atlantic and then tracked into the eastern Caribbean (10-20°N, 75-
60°W) at hurricane strength. Since 1900, only six other years have had eastern Caribbean
hurricanes prior to 1 August: 1926, 1933, 1961, 1996, 2005 and 2020. All six of those
years were classified as hyperactive Atlantic hurricane seasons using the NOAA Atlantic
hurricane season definition (>=160 ACE).

Oh, so 2021 falls into a rare club where the six other seasons average out to 215 ACE, and 4 of them are among the ten most active Atlantic seasons on record in terms of ACE. No that isn’t concerning at all.

And 3 among them had a record-breaking amount of named storms
Definitely not concerning at all

[SFLcane]

Very interesting statement from latest CSU outlook.

7 Hurricane Elsa
In general, early season Atlantic hurricane activity has very little correlation with
overall Atlantic hurricane activity. However, when this activity occurs in the tropics
(south of 23.5°N), that is typically a harbinger of a very active season. Hurricane Elsa
formed in the tropical Atlantic and then tracked into the eastern Caribbean (10-20°N, 75-
60°W) at hurricane strength. Since 1900, only six other years have had eastern Caribbean
hurricanes prior to 1 August: 1926, 1933, 1961, 1996, 2005 and 2020. All six of those
years were classified as hyperactive Atlantic hurricane seasons using the NOAA Atlantic
hurricane season definition (>=160 ACE).

Oh, so 2021 falls into a rare club where the six other seasons average out to 215 ACE, and 4 of them are among the ten most active Atlantic seasons on record in terms of ACE. No that isn’t concerning at all.

Did the hurricanes in those years in July fall apart immediately like Elsa did?

[DestinHurricane]

Very interesting statement from latest CSU outlook.

7 Hurricane Elsa
In general, early season Atlantic hurricane activity has very little correlation with
overall Atlantic hurricane activity. However, when this activity occurs in the tropics
(south of 23.5°N), that is typically a harbinger of a very active season. Hurricane Elsa
formed in the tropical Atlantic and then tracked into the eastern Caribbean (10-20°N, 75-
60°W) at hurricane strength. Since 1900, only six other years have had eastern Caribbean
hurricanes prior to 1 August: 1926, 1933, 1961, 1996, 2005 and 2020. All six of those
years were classified as hyperactive Atlantic hurricane seasons using the NOAA Atlantic
hurricane season definition (>=160 ACE).

Oh, so 2021 falls into a rare club where the six other seasons average out to 215 ACE, and 4 of them are among the ten most active Atlantic seasons on record in terms of ACE. No that isn’t concerning at all.

Did the hurricanes in those years in July fall apart immediately like Elsa did?

Exactly what I mentioned in my post in the indicators thread, I don't think Elsa is equivalent to the hurricanes in those years. Didn't want to post here though because I am not an "expert forecast"

[Category5Kaiju]

Very interesting statement from latest CSU outlook.

7 Hurricane Elsa
In general, early season Atlantic hurricane activity has very little correlation with
overall Atlantic hurricane activity. However, when this activity occurs in the tropics
(south of 23.5°N), that is typically a harbinger of a very active season. Hurricane Elsa
formed in the tropical Atlantic and then tracked into the eastern Caribbean (10-20°N, 75-
60°W) at hurricane strength. Since 1900, only six other years have had eastern Caribbean
hurricanes prior to 1 August: 1926, 1933, 1961, 1996, 2005 and 2020. All six of those
years were classified as hyperactive Atlantic hurricane seasons using the NOAA Atlantic
hurricane season definition (>=160 ACE).

Oh, so 2021 falls into a rare club where the six other seasons average out to 215 ACE, and 4 of them are among the ten most active Atlantic seasons on record in terms of ACE. No that isn’t concerning at all.

Did the hurricanes in those years in July fall apart immediately like Elsa did?

Sure Elsa may have fallen apart when it neared Haiti and the DR, but if you think about it the main reason why it did was because it was simply going too fast to handle and sustain itself, and speed shear really caused the storm to become not as powerful as it could have been. Also here is a very interesting tweet from Brian McNoldy from several days ago:

 https://twitter.com/BMcNoldy/status/1411071122666180611




Sure, Elsa may have been the weaker of the three when compared with the Trinidad storm of 1933 and Emily 2005, but the fact that it achieved hurricane status in the open MDR in early July I think is a very strong indicator that this season has the potential to be an ACE-accumulator and that the MDR baseline conditions are grooming to be very favorable for potent, long-tracked storms later on this season. Not even hyperactive seasons like 1969, 1995, 1999, 2004, 2010, or 2017 had such an early forming MDR system.

[crownweather]

Here's an interesting climate statistic - Bradley Airport in northern Connecticut has had the wettest start to a July since 2005. At my home in Springfield, Mass, I've recorded almost 8 inches of rain in just the last 8 days. Elsa is likely to bring me another 2 to 3 inches of rain.

[Hurricane Mike]

All of those hurricane seasons listed weren't just hyperactive, they were very destructive.

[Teban54]

The CSU forecast now perfectly matches the TSR forecast.

From p. 33 of CSU’s outlook:
https://i.postimg.cc/jdSgYZCs/Ska-rmavbild-2021-07-08-kl-19-54-06.png
Up until now the thirty-day-averaged shear has been running much higher than it typically does during an above-average season. No one has mentioned this yet.

The fact that on this very plot, the average seasons at times have lower shear than above average and even hyperactive seasons in June, suggests to me that June MDR shear has little correlation with seasonal activity. The correlation only comes during the heart of the season.

[AlphaToOmega]

Forecasters are generally forecasting ~20 storms. Last year, they were also forecasting ~20 storms. Potential 2020 repeat

[ouragans]

Forecasters are generally forecasting ~20 storms. Last year, they were also forecasting ~20 storms. Potential 2020 repeat

Last year at the same time, forecast was 24 storms