2020 Indicators: SST's / SAL / MSLP / Steering / Shear / Instability / Sat Images

[Frank2]

So far the ACE this season to date with the 17/5/1 are less than that of which Dorian alone produced last season if that puts things into perspective.

True, but if the Saffir-Simpson scale went up to a Category 6 or even 7, Dorian would have been right there. Not the usual hurricane.

What's happening so far is what some of us have been trying to explain - it's like baking a cake, if just one ingredient is missing or wrong it'll affect the entire matter.

Shear has been strong this year and dry air has been another issue, and why rain over equatorial Africa or low pressures over the MDR does not guarantee a season with one Cat 5 after another.

Again, it's why some meteorologists of my time never favored seasonal forecasts - just too many factors involved and if one is off so will the forecast.

P.S. Hurricane Donna's 60th anniversary of it's landfall near Key Largo is tonight.

Frank

[CyclonicFury]

So far the ACE this season to date with the 17/5/1 are less than that of which Dorian alone produced last season if that puts things into perspective.

True, but if the Saffir-Simpson scale went up to a Category 6 or even 7, Dorian would have been right there. Not the usual hurricane.

What's happening so far is what some of us have been trying to explain - it's like baking a cake, if just one ingredient is missing or wrong it'll affect the entire matter.

Shear has been strong this year and dry air has been another issue, and why rain over equatorial Africa or low pressures over the MDR does not guarantee a season with one Cat 5 after another.

Again, it's why some meteorologists of my time never favored seasonal forecasts - just too many factors involved and if one is off so will the forecast.

P.S. Hurricane Donna's 60th anniversary of it's landfall near Key Largo is tonight.

Frank

Shear was actually well below average in the deep tropics in the weeks leading up to peak, but has increased recently as a strong TUTT has become established over the subtropical Atlantic. This TUTT may be related to be Typhoon Maysak.

I'm becoming more skeptical of the 150-200 ACE forecasts, but I think October could be fairly active due to La Niña and the MJO expected to return. The season is far from over.

[aspen]

Does someone have a list of the ACE per storm in 2005? I want to see how September and October went ACE-wise.

[Extratropical94]

Does someone have a list of the ACE per storm in 2005? I want to see how September and October went ACE-wise.

ID NAME WIND MSLP ACE
--------------------------------------
01L ARLENE 60 989 2.5550
02L BRET 35 1002 0.3675
03L CINDY 65 991 1.5175
04L DENNIS 130 930 18.7550
05L EMILY 140 929 32.8700
06L FRANKLIN 60 997 6.7150
07L GERT 40 1005 0.5275
08L HARVEY 55 994 5.3900
09L IRENE 90 970 13.1375
10L TEN 30 1008 0.0000
11L JOSE 50 998 0.4475
12L KATRINA 150 902 20.0050
13L LEE 35 1006 0.2450
14L MARIA 100 962 14.2650
15L NATE 80 979 7.1700
16L OPHELIA 75 976 15.6725
17L PHILIPPE 70 985 5.9525
18L RITA 155 895 25.1450
19L NINETEEN 30 1006 0.0000
20L STAN 70 977 2.3550
21L UNNAMED 45 997 0.5275
22L TAMMY 45 1001 0.8100
23L TWENTY-TWO 30 1008 0.0000
24L VINCE 65 988 2.6775
25L WILMA 160 882 38.9175
26L ALPHA 45 998 0.6500
27L BETA 100 962 6.4725
28L GAMMA 45 1002 1.3325
29L DELTA 60 980 6.0200
30L EPSILON 75 981 13.3625
31L ZETA 55 994 6.2650
--------------------------------------
SEASON TOTAL: 250.1275

[BYG Jacob]

ACE is the most misused statistic in tracking tropical cyclones.

[TheStormExpert]

ACE is the most misused statistic in tracking tropical cyclones.

How so? Yes it doesn’t go by impact but it definitely tells the story of the season when you have 17 named storms, 5 hurricanes, and 1 major hurricane with a total ACE less of that of for say Dorian of last year.

[TheStormExpert]

So far the ACE this season to date with the 17/5/1 are less than that of which Dorian alone produced last season if that puts things into perspective.

True, but if the Saffir-Simpson scale went up to a Category 6 or even 7, Dorian would have been right there. Not the usual hurricane.

What's happening so far is what some of us have been trying to explain - it's like baking a cake, if just one ingredient is missing or wrong it'll affect the entire matter.

Shear has been strong this year and dry air has been another issue, and why rain over equatorial Africa or low pressures over the MDR does not guarantee a season with one Cat 5 after another.

Again, it's why some meteorologists of my time never favored seasonal forecasts - just too many factors involved and if one is off so will the forecast.

P.S. Hurricane Donna's 60th anniversary of it's landfall near Key Largo is tonight.

Frank

There’s no need for a Cat.6 or 7. Besides there was a storm similar to Dorian back in 1932 which was a season prior to yet another season a lot like this and 2005 in terms of named storms, what a coincidence!

https://en.m.wikipedia.org/wiki/1932_Bahamas_hurricane

And yes I will agree that shear has been strong along with the pesky mid-level dry air that continues to stick around though it’s not as extensive compared to several weeks ago.

Considering this has been a west-based season I’d watch the Western Caribbean next month but as in past active years a system has to be there in order to take advantage of the opportunity.

[CyclonicFury]

ACE is the most misused statistic in tracking tropical cyclones.

How so? Yes it doesn’t go by impact but it definitely tells the story of the season when you have 17 named storms, 5 hurricanes, and 1 major hurricane with a total ACE less of that of for say Dorian of last year.

There's definitely a difference in tracking from the impact perspective compared to the meteorological perspective. ACE means a lot meteorologically but not for impacts. From the meteorological perspective, a strong recurving fish storm like Lorenzo last year is very interesting. From an impact perspective, it is boring. That is why a season like 1992 would be memorable for impacts in the US while a season like 2010 is not. From the impact perspective, a storm like Imelda last year (very little ACE) would be very notable, while from the meteorological perspective it's nothing memorable.

This also applies to the "end" of the season (at least for the U.S. anyway). I often hear that the season ends when a cold front passes through south Florida (usually in mid-late October). This may be true for Florida impacts, but climatologically, there is more likely than not to be another named storm after that date.

[TheStormExpert]

ACE is the most misused statistic in tracking tropical cyclones.

How so? Yes it doesn’t go by impact but it definitely tells the story of the season when you have 17 named storms, 5 hurricanes, and 1 major hurricane with a total ACE less of that of for say Dorian of last year.

There's definitely a difference in tracking from the impact perspective compared to the meteorological perspective. ACE means a lot meteorologically but not for impacts. From the meteorological perspective, a recurving fish storm is very interesting. From an impact perspective, it is boring. That is why a season like 1992 would be memorable for impacts in the US while a season like 2010 is not. From the impact perspective, a storm like Imelda last year (very little ACE) would be very notable, while from the meteorological perspective it's nothing memorable.

This also applies to the "end" of the season (at least for the U.S. anyway). I often hear that the season ends when a cold front passes through south Florida (usually in mid-late October). This may be true for Florida impacts, but climatologically, there is more likely than not to be another named storm after that date.

I know he’s not a fan favorite but didn’t Joe Bastardi come up with an impact scale a while back?

[Extratropical94]

ACE is the most misused statistic in tracking tropical cyclones.

How so? Yes it doesn’t go by impact but it definitely tells the story of the season when you have 17 named storms, 5 hurricanes, and 1 major hurricane with a total ACE less of that of for say Dorian of last year.

There's definitely a difference in tracking from the impact perspective compared to the meteorological perspective. ACE means a lot meteorologically but not for impacts. From the meteorological perspective, a strong recurving fish storm like Lorenzo last year is very interesting. From an impact perspective, it is boring. That is why a season like 1992 would be memorable for impacts in the US while a season like 2010 is not. From the impact perspective, a storm like Imelda last year (very little ACE) would be very notable, while from the meteorological perspective it's nothing memorable.

This also applies to the "end" of the season (at least for the U.S. anyway). I often hear that the season ends when a cold front passes through south Florida (usually in mid-late October). This may be true for Florida impacts, but climatologically, there is more likely than not to be another named storm after that date.

We should have some sort of "land ACE" that only counts storms within xy miles of any land area, but I'm too lazy to set up a shapefile to mask out all the open ocean gridpoints tbh

[CyclonicFury]

How so? Yes it doesn’t go by impact but it definitely tells the story of the season when you have 17 named storms, 5 hurricanes, and 1 major hurricane with a total ACE less of that of for say Dorian of last year.

There's definitely a difference in tracking from the impact perspective compared to the meteorological perspective. ACE means a lot meteorologically but not for impacts. From the meteorological perspective, a strong recurving fish storm like Lorenzo last year is very interesting. From an impact perspective, it is boring. That is why a season like 1992 would be memorable for impacts in the US while a season like 2010 is not. From the impact perspective, a storm like Imelda last year (very little ACE) would be very notable, while from the meteorological perspective it's nothing memorable.

This also applies to the "end" of the season (at least for the U.S. anyway). I often hear that the season ends when a cold front passes through south Florida (usually in mid-late October). This may be true for Florida impacts, but climatologically, there is more likely than not to be another named storm after that date.

We should have some sort of "land ACE" that only counts storms within xy miles of any land area, but I'm too lazy to set up a shapefile to mask out all the open ocean gridpoints tbh

Tropical Storm Risk (TSR) sometimes includes U.S. landfall ACE in their preseason forecasts. I'm sure that is well above average with all the landfalls we've had this season. Whereas in 2010 it would be well below average (but hyperactive ACE from the meteorological perspective).

[Extratropical94]

There's definitely a difference in tracking from the impact perspective compared to the meteorological perspective. ACE means a lot meteorologically but not for impacts. From the meteorological perspective, a strong recurving fish storm like Lorenzo last year is very interesting. From an impact perspective, it is boring. That is why a season like 1992 would be memorable for impacts in the US while a season like 2010 is not. From the impact perspective, a storm like Imelda last year (very little ACE) would be very notable, while from the meteorological perspective it's nothing memorable.

This also applies to the "end" of the season (at least for the U.S. anyway). I often hear that the season ends when a cold front passes through south Florida (usually in mid-late October). This may be true for Florida impacts, but climatologically, there is more likely than not to be another named storm after that date.

We should have some sort of "land ACE" that only counts storms within xy miles of any land area, but I'm too lazy to set up a shapefile to mask out all the open ocean gridpoints tbh

Tropical Storm Risk (TSR) sometimes includes U.S. landfall ACE in their preseason forecasts. I'm sure that is well above average with all the landfalls we've had this season. Whereas in 2010 it would be well below average (but hyperactive ACE from the meteorological perspective).

Afaik, that's only for storms that are already over land and only for the CONUS. So a C4 over PR or a C5 near the coast of Florida wouldn't count towards that metric.

[St0rmTh0r]

I always thought September 10th was considered the average peak. That means that over the past half century or so some seasons conditions and storms peaked in August, some in later September, and some in October. I never took it to mean that date is some holy date for ever single season. That’s not how statistics work.

I think since Cape Verde just started that 2020’s peak could be a bit later than average.

September 10 total cumulative frequency, not the averaged date between a statistical set that occurred earlier or later.

https://i.imgur.com/GB6kpwd.png

Thanks for the clarification!

This still doesn’t say much about individual seasons though. Cumulative scores are still a statistic that isn’t necessarily true for every situation (or in this case season).
For ex., we know for sure the August thru October unquestionably have the peak amount of storms. We know middle/end of august thru beginning of october are peak conditions for the whole Atlantic. However the peak conditions and therefor number of storms can occur anytime in between those. September 10th is smack dab in the middle of that time frame so whether the peak happens before the 10th or after, it’s a safe bet there will be at least 1 named storm active on the date. That doesn’t necessarily mean that date will be peak conditions.
I hope I don’t sound condescending by the way
Taking a statistics class in college just really opened my eyes on how easy it is to misread statistics in situations like these, and I think explaining this may help understand why some hurricane seasons are just different from others......and sooth some nerves about this season

Yea there is no one singular date where conditions peak and then diminish. September 10 is an average of all hurricane activity and formation on that date. It's simply the date of the most observed activity throughout the year. It can't be looked at as a single parameter of the time for peak conditions of any given season because of the parodies year to year. Some years see a longer later peak. Some see a short intense peak before the 10th. This years peak could last well into october or it can end in September. Chances are looking high for this year seeing an extended peak. Gonna be hard for this year to just shutdown with such a strong background state.

[BYG Jacob]

ACE is the most misused statistic in tracking tropical cyclones.

How so? Yes it doesn’t go by impact but it definitely tells the story of the season when you have 17 named storms, 5 hurricanes, and 1 major hurricane with a total ACE less of that of for say Dorian of last year.

It isn't the end all be all and tells you nothing about a season other than how many Cap Verde hurricanes there were.

[Hammy]

ACE is the most misused statistic in tracking tropical cyclones.

How so? Yes it doesn’t go by impact but it definitely tells the story of the season when you have 17 named storms, 5 hurricanes, and 1 major hurricane with a total ACE less of that of for say Dorian of last year.

It isn't the end all be all and tells you nothing about a season other than how many Cap Verde hurricanes there were.

On the first point, we're all but guaranteed to end up with at least average ACE, though I imagine once the monsoon trough moves further south we'll get at least one long tracker. We had a lot of spin-up storms this year that I don't feel would've formed with a normal background state.

On the second point, 2005 barely had any and much of it came from the Gulf. ACE is a combined measurement of intensity and duration of intensity. It is also the sole meterological determinant as to what counts as "hyperactive" as that is based entirely off of ACE reaching a certain point and dismissing the measurement is akin to making up your own meaning for what an active season is. The entire eastern half of the Atlantic basin has so far proven unfavorable for anything to reach hurricane intensity which can't be brushed off at this point.

[toad strangler]

How so? Yes it doesn’t go by impact but it definitely tells the story of the season when you have 17 named storms, 5 hurricanes, and 1 major hurricane with a total ACE less of that of for say Dorian of last year.

It isn't the end all be all and tells you nothing about a season other than how many Cap Verde hurricanes there were.

On the first point, we're all but guaranteed to end up with at least average ACE, though I imagine once the monsoon trough moves further south we'll get at least one long tracker. We had a lot of spin-up storms this year that I don't feel would've formed with a normal background state.

On the second point, 2005 barely had any and much of it came from the Gulf. ACE is a combined measurement of intensity and duration of intensity. It is also the sole meterological determinant as to what counts as "hyperactive" as that is based entirely off of ACE reaching a certain point and dismissing the measurement is akin to making up your own meaning for what an active season is. The entire eastern half of the Atlantic basin has so far proven unfavorable for anything to reach hurricane intensity which can't be brushed off at this point.

I dismiss ACE as I'm not a met and don't work in the field. So ACE means absolutely nothing to me and it never will. What I don't dismiss is Isaias, Hanna, and Laura. THat is my measurement for an active season. This forum is not a scientific term paper for a degree so my requirements for an active season are not bound to a sole metric. God Bless America

[Hammy]

It isn't the end all be all and tells you nothing about a season other than how many Cap Verde hurricanes there were.

On the first point, we're all but guaranteed to end up with at least average ACE, though I imagine once the monsoon trough moves further south we'll get at least one long tracker. We had a lot of spin-up storms this year that I don't feel would've formed with a normal background state.

On the second point, 2005 barely had any and much of it came from the Gulf. ACE is a combined measurement of intensity and duration of intensity. It is also the sole meterological determinant as to what counts as "hyperactive" as that is based entirely off of ACE reaching a certain point and dismissing the measurement is akin to making up your own meaning for what an active season is. The entire eastern half of the Atlantic basin has so far proven unfavorable for anything to reach hurricane intensity which can't be brushed off at this point.

I dismiss ACE as I'm not a met and don't work in the field. So ACE means absolutely nothing to me and it never will. What I don't dismiss is Isaias, Hanna, and Laura. THat is my measurement for an active season. This forum is not a scientific term paper for a degree so my requirements for an active season are not bound to a sole metric. God Bless America

Most of us aren't either, but this is a forum regarding something that has established scientific parameters and we're not going to stop discussing them as a metric.

Similarly, land impacts and total seasonal activity are two completely different matters--you can have an active season with few landfalls, or a quiet season with a lot, and everything in between.

[toad strangler]

On the first point, we're all but guaranteed to end up with at least average ACE, though I imagine once the monsoon trough moves further south we'll get at least one long tracker. We had a lot of spin-up storms this year that I don't feel would've formed with a normal background state.

On the second point, 2005 barely had any and much of it came from the Gulf. ACE is a combined measurement of intensity and duration of intensity. It is also the sole meterological determinant as to what counts as "hyperactive" as that is based entirely off of ACE reaching a certain point and dismissing the measurement is akin to making up your own meaning for what an active season is. The entire eastern half of the Atlantic basin has so far proven unfavorable for anything to reach hurricane intensity which can't be brushed off at this point.

I dismiss ACE as I'm not a met and don't work in the field. So ACE means absolutely nothing to me and it never will. What I don't dismiss is Isaias, Hanna, and Laura. THat is my measurement for an active season. This forum is not a scientific term paper for a degree so my requirements for an active season are not bound to a sole metric. God Bless America

Most of us aren't either, but this is a forum regarding something that has established scientific parameters and we're not going to stop discussing them as a metric.

Similarly, land impacts and total seasonal activity are two completely different matters--you can have an active season with few landfalls, or a quiet season with a lot, and everything in between.

I wouldn't expect anyone to stop discussing the metric nor did I suggest it. I just dismiss it as a sole determination.

[Hammy]

I dismiss ACE as I'm not a met and don't work in the field. So ACE means absolutely nothing to me and it never will. What I don't dismiss is Isaias, Hanna, and Laura. THat is my measurement for an active season. This forum is not a scientific term paper for a degree so my requirements for an active season are not bound to a sole metric. God Bless America

Most of us aren't either, but this is a forum regarding something that has established scientific parameters and we're not going to stop discussing them as a metric.

Similarly, land impacts and total seasonal activity are two completely different matters--you can have an active season with few landfalls, or a quiet season with a lot, and everything in between.

I wouldn't expect anyone to stop discussing the metric nor did I suggest it. I just dismiss it as a sole determination.

I won't disagree on that.

It is interesting though to use different metrics and compare seasons to each other so personally I'll use whatever I can get.

[tolakram]

Unless most of the models are wrong, and they could very well be, Cape Verde season is about to begin. There's always a chance that 2020 will be another line on that ACE graph that shows a delayed start to the big ACE producers and yet still manages to produce a lot of ACE. Looks like it's going to be a very interesting September, regardless.