2017 indicators: SST's / MSLP / SAL / Steering / Instability

[Ntxw]

I'll throw my two cents in here on a statistical aspect. Alyono pointed out in I believe earlier in this thread (or it could've been another) that perhaps ACE isn't a good indicator of activity and I'm thinking that might be true, because Harvey will have only added about 10 points or so, despite being a Cat 4, thanks to the shorter lifespan (as it wasn't a long tracking Cabo Verde system). We're currently at about 24 ACE or so, so what's to say we don't have 4 similar storms to Gert and Harvey, Cat 3s and 4s that form further west, and a say another Cat 1 in the Gulf or western Caribbean, and then maybe five more tropical storms--we could easily end up with something like 17/7/4 and around 55-65 ACE in that setup--perhaps we need something like ACE that is based solely on the peak intensity.

You are right ACE is not the perfect depiction for an entire hurricane season. But it is better than numbers of storms. Neither depict impacts to land and until there is a better scale that is agreed upon, it is what NOAA uses to rank seasons and measure their activity. ACE focuses on the energy around the center of the system, not all of the various impacts around it such as the trillions of gallons of rainfall water, surge, etc

[Hammy]

I'll throw my two cents in here on a statistical aspect. Alyono pointed out in I believe earlier in this thread (or it could've been another) that perhaps ACE isn't a good indicator of activity and I'm thinking that might be true, because Harvey will have only added about 10 points or so, despite being a Cat 4, thanks to the shorter lifespan (as it wasn't a long tracking Cabo Verde system). We're currently at about 24 ACE or so, so what's to say we don't have 4 similar storms to Gert and Harvey, Cat 3s and 4s that form further west, and a say another Cat 1 in the Gulf or western Caribbean, and then maybe five more tropical storms--we could easily end up with something like 17/7/4 and around 55-65 ACE in that setup--perhaps we need something like ACE that is based solely on the peak intensity.

You are right ACE is not the perfect depiction for an entire hurricane season. But it is better than numbers of storms. Neither depict impacts to land and until there is a better scale that is agreed upon, it is what NOAA uses to rank seasons and measure their activity. ACE focuses on the energy around the center of the system, not all of the various impacts around it such as the trillions of gallons of rainfall water, surge, etc

My point was more that longevity is weighted too much on the current scale--a longer-lived Cat 1 or tropical storm has the potential to produce more ACE than a shorter-lived Cat 4 or 5 hurricane, whereas ranking by what the maximum peak is could be used instead, or at least in tandem with the current ACE scale. Look at Nadine for instance, with 26 ACE points peaking at 80kt, vs about 10 for Harvey, which peaked at 115kt.

[Ntxw]

I'll throw my two cents in here on a statistical aspect. Alyono pointed out in I believe earlier in this thread (or it could've been another) that perhaps ACE isn't a good indicator of activity and I'm thinking that might be true, because Harvey will have only added about 10 points or so, despite being a Cat 4, thanks to the shorter lifespan (as it wasn't a long tracking Cabo Verde system). We're currently at about 24 ACE or so, so what's to say we don't have 4 similar storms to Gert and Harvey, Cat 3s and 4s that form further west, and a say another Cat 1 in the Gulf or western Caribbean, and then maybe five more tropical storms--we could easily end up with something like 17/7/4 and around 55-65 ACE in that setup--perhaps we need something like ACE that is based solely on the peak intensity.

You are right ACE is not the perfect depiction for an entire hurricane season. But it is better than numbers of storms. Neither depict impacts to land and until there is a better scale that is agreed upon, it is what NOAA uses to rank seasons and measure their activity. ACE focuses on the energy around the center of the system, not all of the various impacts around it such as the trillions of gallons of rainfall water, surge, etc

My point was more that longevity is weighted too much on the current scale--a longer-lived Cat 1 or tropical storm has the potential to produce more ACE than a shorter-lived Cat 4 or 5 hurricane, whereas ranking by what the maximum peak is could be used instead, or at least in tandem with the current ACE scale. Look at Nadine for instance, with 26 ACE points peaking at 80kt, vs about 10 for Harvey, which peaked at 115kt.

There is no perfect answer. A cat 5 half the size of a 3 that lasts for a day or two isn't pumping more energy out of the ocean say to a major/cat 4 that lasts 3-4 days..its the best system we have at the moment until there is something more agree-able which has not come easy for the many great minds.

[Steve]

While a drop in the bucket for 3 months as compared to 3 days in Houston 2017, this is the rainiest June 1-August 31 in the history of New Orleans. Some of it was tropical in nature, but maybe excess moisture in the South Central US is a symptom or even possibly an indicator of future tropical influx? I always said the summer reminded me of spring in 2003 when it flooded over and over. We got TS Bill early that year. Excess rains were later this year, and obviously Harvey in the vicinity is much later than Bill was. I'm not sure if there is a correlation, but it's something to file away for future years.

2017 now moving into the peak with continued activity ahead. No telling how it's all going to play out, but we still have about 75-80 points of ACE to get to average.

[RL3AO]

So next year when we have heavy dust in July and August and people scream season cancel, we will have Irma to point to.

[Emmett_Brown]

We reached the "I" storm in August, and Harvey's devastating blow broke the years long streak without a major impacting the CONUS. August turned out to be quite a bit busier than many thought.

[RL3AO]

We reached the "I" storm in August, and Harvey's devastating blow broke the years long streak without a major impacting the CONUS. August turned out to be quite a bit busier than many thought.

Amazing to think that 10 days ago the tone was much different on here.

[cycloneye]

We reached the "I" storm in August, and Harvey's devastating blow broke the years long streak without a major impacting the CONUS. August turned out to be quite a bit busier than many thought.

Amazing to think that 10 days ago the tone was much different on here.

2013 was the theme but that is much gone now.

[NDG]

So next year when we have heavy dust in July and August and people scream season cancel, we will have Irma to point to.

But you know that would be in a perfect world, people have short memories

[NDG]

We reached the "I" storm in August, and Harvey's devastating blow broke the years long streak without a major impacting the CONUS. August turned out to be quite a bit busier than many thought.

Amazing to think that 10 days ago the tone was much different on here.

2013 was the theme but that is much gone now.

Harvey and now Irma have definitely buried 2013 as an analog year.

[RL3AO]

Remember this graph about two weeks ago. Wonder why it hasn't been posted recently.

[Steve]

Hahaha. I mean it's natural to wonder what's going to happen when things aren't going like you think they would. But July pretty much is always July. We just had a bit of a jump on the numbers this year. Several pages back between arguing over the future, I did note that I thought that we were well on our way to the mid-teens for named storms. Probably a good chance that TD 10 might have been the "I" storm at some point, but I didn't watch it closely enough. We will hit J (#10) named storm on the next system. And we're still not to September this year. I don't think we go hyper (by number of storms) and certainly not by hyper ACE unless we get like 5 majors with at least a couple of them lasting a while. Kind of scary potential ahead in September and possibly October.

[Kingarabian]

From Mike Ventrice:



I can see why Irma is doing so well with all that rising air just off the west coast of Africa. But this EPS forecast will likely verify wrong if Irma becomes a major hurricane in the areas that are dominated by sinking air.

[Hammy]

From Aug 19:

Conditions are far worse than last year and look like they'll stay that way for the forseeable future and my confidence in this year being above normal has essentially collapsed at this point. CFS (which has been over-estimating intensity) is gradually backing off on rain/hurricane activity for September and October, and models continue to show little to nothing--if 92L doesn't develop and Harvey doesn't strengthen, it tells me that the model failure with Gert was nothing more than a fluke, and not part of a larger calibration problem. If things don't change in the next few weeks, then I'll say probably three more hurricanes the rest of the season (and no majors).

Needless to say things have changed in the last 11 days. I mentioned 2003 some time ago as a possible SST analog so that could be in play now.

[1900hurricane]

From Mike Ventrice:



I can see why Irma is doing so well with all that rising air just off the west coast of Africa. But this EPS forecast will likely verify wrong if Irma becomes a major hurricane in the areas that are dominated by sinking air.

This is going to be an Irma-centric post, but you know, that actually reminds me quite a bit of an El Nino WPac set-up. Irma has developed and established itself well to the east with the rising motion. Upper level subsidence exists to the west, but it shouldn't bother an established system, like the many east-developing systems in a WPac El Nino year. Looks like some serious long-track potential to me.

[1900hurricane]

I'll throw my two cents in here on a statistical aspect. Alyono pointed out in I believe earlier in this thread (or it could've been another) that perhaps ACE isn't a good indicator of activity and I'm thinking that might be true, because Harvey will have only added about 10 points or so, despite being a Cat 4, thanks to the shorter lifespan (as it wasn't a long tracking Cabo Verde system). We're currently at about 24 ACE or so, so what's to say we don't have 4 similar storms to Gert and Harvey, Cat 3s and 4s that form further west, and a say another Cat 1 in the Gulf or western Caribbean, and then maybe five more tropical storms--we could easily end up with something like 17/7/4 and around 55-65 ACE in that setup--perhaps we need something like ACE that is based solely on the peak intensity.

There are so many stats that can be gathered or derived. It's actually a lot like baseball in that regard. There are your storm counts, which are like your simple baseball stats like batting average, hits, home runs, ERA, and the like. Stuff like ACE, PDI, and storm durations is a bit of a step up in terms of both complexity and usefulness, so similar to stuff like OPS, WHIP, and WAR. Then there are many other types of stats that can be derived, and when coupled with the other data, can bring out all sorts of useful information, kind of like Sabermetrics. I'm somewhat of a stats junkie myself, so I keep track of all sorts of these stats.





Here's just a taste of the kinds of stats I'm putting together.

[gatorcane]

Well looks like we are finally seeing the MDR really get going. Early indicators definitely pointed to an active MDR and it looks like those indicators are correct. Now let's hope these system stay away from land.

[NDG]

Not surprising after seeing Irma today, it makes sense that shear over the MDR is the lowest since 2008.

 https://twitter.com/MichaelRLowry/status/903321051400196096

[CyclonicFury]

Not surprising after seeing Irma today, it makes sense that shear over the MDR is the lowest since 2008.

 https://twitter.com/MichaelRLowry/status/903321051400196096

The Atlantic is finally starting to take off. 9-4-2 and it's on August 31. ACE still slightly below normal but that should not be the case in a few days. Chances of a below average season are slipping quickly. Shear is low, the SST configuration is very favorable, and we are starting to see some stronger storms this month.

[Steve]

Well looks like we are finally seeing the MDR really get going. Early indicators definitely pointed to an active MDR and it looks like those indicators are correct. Now let's hope these system stay away from land.

I kind of saw it the other way before the season when the MDR was cold. It heated up, but it seemed like the first low to sit off NW Africa would send the colder currents to knock it back. But that didn't happen. I still don't think it's going to be an MDR season per se, but clearly the potential for storms to form in that region is there.

I know Alyono was conflicted a few weeks ago on how things would turn out after the EC was indicating the possibility of less numbers but higher ACE generating storms. We got back to back majors in August. And everyone knows many of the last few years had more hurricanes later and on the back side of the season as we have tended to have warmer weather overall through the fall. It could be a product of how warm the Atlantic has been or wherever we are at in the warm AMO phase. A lot of people like to speculate we flipped back to the 1970-94 era. But I don't see it yet. As long as the ocean is warm, there will be an opportunity for big seasons. 2017 is infamous for Harvey already even though we are barely up to 30 ACE. I don't know how many more storms we will have or how much more ACE we will get. But with the strength and breadth of the Atlantic High, and a mean trough position well past 100W, the US is open more than it isn't. We could easily see another few impacts of whatever strength comes up.