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

This is the general tropical discussion area. Anyone can take their shot at predicting a storms path.

Moderator: S2k Moderators

Forum rules

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

Help Support Storm2K
Message
Author
User avatar
aspen
Category 5
Category 5
Posts: 8818
Joined: Sat Oct 12, 2019 7:10 pm
Location: Connecticut, USA

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

#921 Postby aspen » Sun Jul 04, 2021 8:59 am

2021 is one of a handful of years with a deep tropics MDR system, so once again looking to see the average of similar years, I limited this sample to seasons after 1980 with at least one July system born from an AEW east of 70W and south of 25N, regardless of intensity. The seasons that fit this criteria are 1989, 1990, 1995 (just barely), 1996, 1998, 2003, 2005, 2008, 2013, 2017, 2018, and 2020. Their average numbers are:
—17.3 named storms
—9.1 hurricanes
—3.9 majors
—162.80 ACE

I then decided to remove 2013 from the calculations, because despite having two July MDR systems, the season’s H, MH, and ACE total were destroyed by the abnormal collapse of the THC, thereby making it an outlier due to the occurrence of a rare event. The new average is:
—17.5 named storms
—9.7 hurricanes
—4.3 majors
—174.32 ACE

Since 2021 now falls into this category with Hurricane Elsa, it is quite probable that the year ends up with 15-19 named storms, 7-10 hurricanes, 3-5 majors, and an ACE total of at least 140-150.
7 likes   
Irene '11 Sandy '12 Hermine '16 5/15/2018 Derecho Fay '20 Isaias '20 Elsa '21 Henri '21 Ida '21

I am only a meteorology enthusiast who knows a decent amount about tropical cyclones. Look to the professional mets, the NHC, or your local weather office for the best information.

User avatar
Category5Kaiju
Category 5
Category 5
Posts: 4097
Joined: Thu Dec 24, 2020 12:45 pm
Location: Seattle

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

#922 Postby Category5Kaiju » Sun Jul 04, 2021 9:10 am

Shell Mound wrote:
Hammy wrote:
Shell Mound wrote:On the other hand, does Elsa’s compact size while intensifying over the Windwards suggest that it is less representative of background conditions than a larger TC?

In other words, does the fact that Elsa was a relatively small system suggest that it says less about overall conditions in 2021 than a larger system might have...?


July storms aren't typically that large in the first place as pressures in that part of the Atlantic in early July are generally higher than in August and September. Even Emily in 2005 (the most active July on record, and the strongest July hurricane on record) was small through most of it's life prior to crossing the Yucatan and spreading out. Both Berthas in 1996 and 2008 were also fairly small once they organized.

The fact that Elsa is weakening in the Caribbean, unlike storms in June/July 1933 and 2005, suggests this season is likely to be less favourable than those two.


I don’t mean any offense, but I strongly disagree with this notion. The fact that we had Elsa by itself is a warning sign for what is to come, and here’s a list of very bad hurricane seasons that did not have a July MDR hurricane: 2004, 2017, 1969, 2020. I think this season has shown to overachieve based on this metric alone, and if anything the fact that Elsa survived an otherwise hostile ECAR and took a cruiser-like path may suggest that we could even see the return of Caribbean cruisers later this season assuming this is an indication that conditions in this region of the Atlantic are abnormally favorable.
6 likes   
Unless explicitly stated, all info in my posts is based on my own opinions and observations. Tropical storms and hurricanes can be extremely dangerous. Do not think you can beat Mother Nature. Refer to an accredited weather research agency or meteorologist if you need to make serious decisions regarding an approaching storm.

AlphaToOmega
Category 5
Category 5
Posts: 1448
Joined: Sat Jun 26, 2021 10:51 am
Location: Somewhere in Massachusetts

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

#923 Postby AlphaToOmega » Sun Jul 04, 2021 12:14 pm

aspen wrote:2021 is one of a handful of years with a deep tropics MDR system, so once again looking to see the average of similar years, I limited this sample to seasons after 1980 with at least one July system born from an AEW east of 70W and south of 25N, regardless of intensity. The seasons that fit this criteria are 1989, 1990, 1995 (just barely), 1996, 1998, 2003, 2005, 2008, 2013, 2017, 2018, and 2020. Their average numbers are:
—17.3 named storms
—9.1 hurricanes
—3.9 majors
—162.80 ACE

I then decided to remove 2013 from the calculations, because despite having two July MDR systems, the season’s H, MH, and ACE total were destroyed by the abnormal collapse of the THC, thereby making it an outlier due to the occurrence of a rare event. The new average is:
—17.5 named storms
—9.7 hurricanes
—4.3 majors
—174.32 ACE

Since 2021 now falls into this category with Hurricane Elsa, it is quite probable that the year ends up with 15-19 named storms, 7-10 hurricanes, 3-5 majors, and an ACE total of at least 140-150.


I would exclude 1989 and 1990 for being -AMO. With that, the seasons with early July MDR activity are 1995, 1996, 1998, 2003, 2005, 2008, 2017, 2018, and 2020. In that case, the averages are:
—18.66 storms
—10.22 hurricanes
—4.88 major hurricanes
—186.77 ACE

Based on these analogs alone, a reasonable forecast for 2021 would be 18-19 storms, 10-11 hurricanes, 4-5 major hurricanes, and 180-190 ACE.
0 likes   

Deshaunrob17
Tropical Storm
Tropical Storm
Posts: 207
Joined: Tue Aug 18, 2020 7:49 am

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

#924 Postby Deshaunrob17 » Sun Jul 04, 2021 12:45 pm

1998 season was an interesting year IMO. The year before we had the super elnino . During 1998 , La Niña signal started to build from the west in the Pacific . However, when September came, this Eastern Pacific still had residual El Niño signal as it was still pretty anomalously warm. Even though the eastern side of the Pacific was warm, we had Hurricane Gorges and Hurricane Mitch in the Caribbean. However, the Caribbean wasn’t too active compared to the MDR (I’m guessing the the residual warm pool in the Epac).

I’m looking at this. Year and it seems like the Eastern side of the Pacific taking quite some time to cool down . The Central Pacific seems neutral.. Not too sure about it being a heavy Caribbean year, but definitely looks like it will be a heavy MDR year
1 likes   

User avatar
aspen
Category 5
Category 5
Posts: 8818
Joined: Sat Oct 12, 2019 7:10 pm
Location: Connecticut, USA

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

#925 Postby aspen » Sun Jul 04, 2021 4:04 pm

According to CSU, we’re up to 8.0 units of ACE so far. Maybe it’ll be up to 10 units by the time Elsa dissipates, very impressive for the first week of July. In fact, this is roughly the average ACE by early August.

http://tropical.atmos.colostate.edu/Realtime/
Last edited by aspen on Sun Jul 04, 2021 4:08 pm, edited 1 time in total.
1 likes   
Irene '11 Sandy '12 Hermine '16 5/15/2018 Derecho Fay '20 Isaias '20 Elsa '21 Henri '21 Ida '21

I am only a meteorology enthusiast who knows a decent amount about tropical cyclones. Look to the professional mets, the NHC, or your local weather office for the best information.

User avatar
cycloneye
Admin
Admin
Posts: 145307
Age: 68
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

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

#926 Postby cycloneye » Sun Jul 04, 2021 4:07 pm

0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
aspen
Category 5
Category 5
Posts: 8818
Joined: Sat Oct 12, 2019 7:10 pm
Location: Connecticut, USA

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

#927 Postby aspen » Sun Jul 04, 2021 4:10 pm


The enhanced CCKW following the suppressive wave will probably lead to a spike in TC activity starting in the last third of July. That’s when I think we’ll get our next hurricane and maybe even the first major.
1 likes   
Irene '11 Sandy '12 Hermine '16 5/15/2018 Derecho Fay '20 Isaias '20 Elsa '21 Henri '21 Ida '21

I am only a meteorology enthusiast who knows a decent amount about tropical cyclones. Look to the professional mets, the NHC, or your local weather office for the best information.

AlphaToOmega
Category 5
Category 5
Posts: 1448
Joined: Sat Jun 26, 2021 10:51 am
Location: Somewhere in Massachusetts

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

#928 Postby AlphaToOmega » Sun Jul 04, 2021 4:17 pm

A suppressed MJO phase does not exclude subtropical development.
Last edited by AlphaToOmega on Sun Jul 04, 2021 4:57 pm, edited 1 time in total.
2 likes   

User avatar
Hammy
Category 5
Category 5
Posts: 5849
Age: 41
Joined: Fri May 25, 2012 5:25 pm
Contact:

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

#929 Postby Hammy » Sun Jul 04, 2021 4:44 pm

Shell Mound wrote:
Hammy wrote:
Shell Mound wrote:On the other hand, does Elsa’s compact size while intensifying over the Windwards suggest that it is less representative of background conditions than a larger TC?

In other words, does the fact that Elsa was a relatively small system suggest that it says less about overall conditions in 2021 than a larger system might have...?


July storms aren't typically that large in the first place as pressures in that part of the Atlantic in early July are generally higher than in August and September. Even Emily in 2005 (the most active July on record, and the strongest July hurricane on record) was small through most of it's life prior to crossing the Yucatan and spreading out. Both Berthas in 1996 and 2008 were also fairly small once they organized.

The fact that Elsa is weakening in the Caribbean, unlike storms in June/July 1933 and 2005, suggests this season is likely to be less favourable than those two.


By that same logic, you could have said that because Isaias was weakening in the Bahamas suggests 2020 wouldn't be as favorable as 2019.

aspen wrote:

The enhanced CCKW following the suppressive wave will probably lead to a spike in TC activity starting in the last third of July. That’s when I think we’ll get our next hurricane and maybe even the first major.



What I'm taking from this is that July is essentially trying to behave like August, given how often the middle of August itself has had complete lulls only to heat up at the end.
5 likes   
The above post is not official and should not be used as such. It is the opinion of the poster and may or may not be backed by sound meteorological data. It is not endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

AlphaToOmega
Category 5
Category 5
Posts: 1448
Joined: Sat Jun 26, 2021 10:51 am
Location: Somewhere in Massachusetts

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

#930 Postby AlphaToOmega » Sun Jul 04, 2021 5:00 pm

The one advantage the Atlantic has over the East Pacific is subtropical development. I do not think subtropical storms form in the East Pacific (if they do, they must be EXTREMELY rare), but they are quite common in the Atlantic. This year, both the subtropics and the tropics are forecasted to have above-average sea surface temperatures, which would enhance both tropical and subtropical activity.
0 likes   

User avatar
Kingarabian
S2K Supporter
S2K Supporter
Posts: 15980
Joined: Sat Aug 08, 2009 3:06 am
Location: Honolulu, Hawaii

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

#931 Postby Kingarabian » Sun Jul 04, 2021 5:02 pm

AlphaToOmega wrote:The one advantage the Atlantic has over the East Pacific is subtropical development. I do not think subtropical storms form in the East Pacific (if they do, they must be EXTREMELY rare), but they are quite common in the Atlantic. This year, both the subtropics and the tropics are forecasted to have above-average sea surface temperatures, which would enhance both tropical and subtropical activity.

They do form but they're not classified.
2 likes   
RIP Kobe Bryant

User avatar
Category5Kaiju
Category 5
Category 5
Posts: 4097
Joined: Thu Dec 24, 2020 12:45 pm
Location: Seattle

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

#932 Postby Category5Kaiju » Sun Jul 04, 2021 7:01 pm

Also interesting thing to note: once Elsa hits Florida, we would be ahead of 2020 in the number of NS landfalls in the continental US based on when we are in the calendar.
0 likes   
Unless explicitly stated, all info in my posts is based on my own opinions and observations. Tropical storms and hurricanes can be extremely dangerous. Do not think you can beat Mother Nature. Refer to an accredited weather research agency or meteorologist if you need to make serious decisions regarding an approaching storm.

User avatar
aspen
Category 5
Category 5
Posts: 8818
Joined: Sat Oct 12, 2019 7:10 pm
Location: Connecticut, USA

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

#933 Postby aspen » Mon Jul 05, 2021 6:04 am

It is only July 5th, and there is a Caribbean Cruiser that was a MDR hurricane and had the chance to become a major. If the Atlantic was able to pump this out in a historically “eh” month, what will it be putting out once ASO arrives? The position of the ITCZ, as posted by Hammy, seems to be better for MDR activity, so therefore it could favor more low-riders that turn into Caribbean Cruisers.
8 likes   
Irene '11 Sandy '12 Hermine '16 5/15/2018 Derecho Fay '20 Isaias '20 Elsa '21 Henri '21 Ida '21

I am only a meteorology enthusiast who knows a decent amount about tropical cyclones. Look to the professional mets, the NHC, or your local weather office for the best information.

User avatar
CyclonicFury
Category 5
Category 5
Posts: 2025
Age: 26
Joined: Sun Jul 02, 2017 12:32 pm
Location: NC
Contact:

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

#934 Postby CyclonicFury » Mon Jul 05, 2021 9:47 am

After Elsa, the Atlantic will likely have a lull. The exact duration of how long is hard to predict, but it would not be surprising to not see a TC form for 2-3 weeks. That being said, there's always potential for unexpected short lived weak storms. With the upcoming suppressed CCKW, we could see a significant SAL outbreak as well. Then it'll be season cancel season.

I'd expect the Atlantic to really get going in late August, as usual. Maybe a few named storms and even a hurricane before then.
6 likes   
NCSU B.S. in Meteorology Class of 2021. Tropical weather blogger at http://www.cyclonicfury.com. My forecasts and thoughts are NOT official, for official forecasts please consult the National Hurricane Center.

AlphaToOmega
Category 5
Category 5
Posts: 1448
Joined: Sat Jun 26, 2021 10:51 am
Location: Somewhere in Massachusetts

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

#935 Postby AlphaToOmega » Mon Jul 05, 2021 10:02 am

As of now, most tropical cyclogenesis has been in the subtropics (Ana, Bill, and Danny). One of these was in May; the two others were in June. We would see 1-2 tropical cyclones form in the subtropics in July. The latest CFSv2 run shows a suppressed phase until ~July 19. At that point, activity should ramp up again.
0 likes   

User avatar
Category5Kaiju
Category 5
Category 5
Posts: 4097
Joined: Thu Dec 24, 2020 12:45 pm
Location: Seattle

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

#936 Postby Category5Kaiju » Mon Jul 05, 2021 1:05 pm

CyclonicFury wrote:After Elsa, the Atlantic will likely have a lull. The exact duration of how long is hard to predict, but it would not be surprising to not see a TC form for 2-3 weeks. That being said, there's always potential for unexpected short lived weak storms. With the upcoming suppressed CCKW, we could see a significant SAL outbreak as well. Then it'll be season cancel season.

I'd expect the Atlantic to really get going in late August, as usual. Maybe a few named storms and even a hurricane before then.


While I agree with you, I think the GFS has been hinting at some development in the WCAR as early as next week. We'll see if that verifies, but this just shows you that even during a suppressed phase how activity can still occur.
0 likes   
Unless explicitly stated, all info in my posts is based on my own opinions and observations. Tropical storms and hurricanes can be extremely dangerous. Do not think you can beat Mother Nature. Refer to an accredited weather research agency or meteorologist if you need to make serious decisions regarding an approaching storm.

AlphaToOmega
Category 5
Category 5
Posts: 1448
Joined: Sat Jun 26, 2021 10:51 am
Location: Somewhere in Massachusetts

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

#937 Postby AlphaToOmega » Mon Jul 05, 2021 1:27 pm

It is also possible for major hurricanes to form in the subtropics. This is what happened with Hurricane Epsilon (2020).
0 likes   

User avatar
Category5Kaiju
Category 5
Category 5
Posts: 4097
Joined: Thu Dec 24, 2020 12:45 pm
Location: Seattle

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

#938 Postby Category5Kaiju » Mon Jul 05, 2021 1:32 pm

Or Hurricane Alex back in 2004, that became a Cat 3 at an unusually high latitude
0 likes   
Unless explicitly stated, all info in my posts is based on my own opinions and observations. Tropical storms and hurricanes can be extremely dangerous. Do not think you can beat Mother Nature. Refer to an accredited weather research agency or meteorologist if you need to make serious decisions regarding an approaching storm.

User avatar
captainbarbossa19
Professional-Met
Professional-Met
Posts: 1092
Age: 27
Joined: Wed Aug 21, 2019 11:09 pm
Location: Beaumont, TX

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

#939 Postby captainbarbossa19 » Mon Jul 05, 2021 2:12 pm

AlphaToOmega wrote:This is probably one of the most favorable SST patterns for an active season
https://www.tropicaltidbits.com/analysis/models/cfs-mon/2021070400/cfs-mon_01_ssta_global_2.png


Somehow, I think the western part of the basin may be more favorable compared to the MDR yet again this season. Wind shear sure has been relatively low in the Caribbean lately.
0 likes   

AlphaToOmega
Category 5
Category 5
Posts: 1448
Joined: Sat Jun 26, 2021 10:51 am
Location: Somewhere in Massachusetts

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

#940 Postby AlphaToOmega » Mon Jul 05, 2021 2:18 pm

captainbarbossa19 wrote:
AlphaToOmega wrote:This is probably one of the most favorable SST patterns for an active season
https://www.tropicaltidbits.com/analysis/models/cfs-mon/2021070400/cfs-mon_01_ssta_global_2.png


Somehow, I think the western part of the basin may be more favorable compared to the MDR yet again this season. Wind shear sure has been relatively low in the Caribbean lately.

Last year's SST pattern was horrible for MDR development. The MDR was practically below-average. I am not seeing that on the forecast.
0 likes   


Return to “Talkin' Tropics”

Who is online

Users browsing this forum: BobHarlem, cycloneye, CyclonicFury, KeysRedWine, NotSparta, TomballEd, Ulf and 55 guests