Seasonal Indicators (Beyond Day 16): Instability / SST's / MSLP / Steering / Sal

[LarryWx]

Anyone with good knowledge is welcome to answer, but this is geared a bit more towards Larry. As many may know, I picked 1959, 1985, and 1992 as the best analogs coming into this year. However, 1998 has been mentioned as a possible analog too, and I can kind of agree that there are some similarities with that year too.

My question is, Larry or anyone, is there information on if the MJO was in the "circle of death" in any of the years before 1995 for the latter half of September? I see Georges fits the mold for 1998, but I wonder about Gloria and Gracie (not that hopes are high on the latter, it was 1959 after all!) I would also be curious if we were not in that circle in late September 1992, given the lack of major threats to land that we saw in the other three years in that period, even though Danielle still reached the East Coast as a decent tropical storm that year.

I just worry a little looking at all the similarities with this year and those four years to date that we may not have seen the biggest storm to come. I hope I am wrong when I say that.

-Andrew92

Hey Andrew,
In late Sep. of 1992, the MJO was inside the circle on some days and just outside the circle in phases 1-2 on other days.
In late Sep, of 1985, the MJO was mainly within the circle. Gloria was an inside the circle birth.
MJO phase data is not available for 1959.

[Ntxw]

ACE is a little behind now but still within striking distance after going above. Partly because this is peak of season and the average is growing quickly. By the end of the month we will need to be at 80-85 units to be near normal. This is the period which the majority of a typical season's ACE is accumulated. Right now we stand at about 41-42 units and will need another 40 or so units. To put into perspective Hermine added about 3.5 units altogether. Gaston about 25 units. So the Atlantic will need another, possibly two, long tracking canes similar to Gaston by the end of the month to keep pace.

[Andrew92]

Thanks a lot Larry! I knew you would have good information on those years, except 1959 which doesn't surprise me at all given how far back that is.

As for 1998 versus the others I listed, I like that analog up to this point. However, it is about to be tested in a big way. Georges became a major hurricane south of 20 degrees; the other years didn't have one in those tropical latitudes in the Atlantic.

You could say that October needs to be watched as well, due to Mitch. However, I found that major hurricanes in October and November in the Caribbean usually only occur if there has been a major hurricane earlier in the year south of 20 degrees. Rina and Sandy recently broke that mold (though Rina is a very borderline case at best), but the last time before then to see an October/November major in the Caribbean with no 20-degrees or south majors in the Atlantic was 1954 if I am right. That's the kind of odds we have for a late-season major in the Caribbean if nothing happens south of 20 this month: not good. The other three analogs didn't have October or November majors in the Caribbean.

-Andrew92

[Andrew92]

Turns out my post above was inaccurate. 2001 and 2008 had no majors south of 20 degrees before October either. But Iris and Michelle, along with Omar and Paloma, became majors in the late season months. 1963 also saw Flora maybe do the same thing, though that one is borderline as it may have been a major on 9/30 upon entering the Caribbean.

It's still a pretty uncommon event though, and if there are no majors before October this year south of 20 degrees, there probably won't be any after that either.....but it is possible.

-Andrew92

[cycloneye]

 https://twitter.com/MJVentrice/status/774585391697584128

[Alyono]

which is why I would not be surprised if aside from the central Atlantic system, we see MAYBE only 1 other storm in September

[SFLcane]

Bunch of sheared lows for sept peak season..Why Iam I not surprised??

[cycloneye]

 https://twitter.com/philklotzbach/status/774609291374235649

[tolakram]

I say we get one more major, possibly 94L, then 1 more hurricane and maybe a couple of tropical storms.

Season ends up near or slightly below normal.

It's interesting how instability has returned to near normal after a number of years of below normal but the dry air persists.

[tarheelprogrammer]

Well my final prediction I gave in July was at 10/3/1....I will probably be very close. Things could change but glad to see that I may have had a good grip on it all the way back then. It is actually getting easy to predict the Atlantic seasons now. Either it is OTS or being limited by shear and dry air.

[tolakram]

Well my final prediction I gave in July was at 10/3/1....I will probably be very close. Things could change but glad to see that I may have had a good grip on it all the way back then. It is actually getting easy to predict the Atlantic seasons now. Either it is OTS or being limited by shear and dry air.

Conditions in the Atlantic are completely different from earlier in the season so I'm a little confused. Instability is higher than it's been for years, literally years, shear is normal, ridges are more prevalent. The only thing that has not changed is the dry air.

[Yellow Evan]

Even 2013 had 6 storms and 1 hurricane after this date. I'd say we get 5-7 more, and possibly another Cat 3/4/5.

[Frank2]

Per the TWO the easterlies are already breaking down - a sure sign of Fall...

[tarheelprogrammer]

Well my final prediction I gave in July was at 10/3/1....I will probably be very close. Things could change but glad to see that I may have had a good grip on it all the way back then. It is actually getting easy to predict the Atlantic seasons now. Either it is OTS or being limited by shear and dry air.

Conditions in the Atlantic are completely different from earlier in the season so I'm a little confused. Instability is higher than it's been for years, literally years, shear is normal, ridges are more prevalent. The only thing that has not changed is the dry air.

Yeah it is weird lately. It is like the basin finds a way to stop TC development in the western part of the basin. The western part of the basin was supposed to be favorable this season but not so much. Wonder if it will ever change.

[Alyono]

5 of the 8 storms have been in the western part of the basin. As was the unnamed depression. So 6 of 9 (or if you don't count Alex 6 of 8) cyclones this year have been west of 70W.

The western part of the basin has been favorable, as expected

[tarheelprogrammer]

5 of the 8 storms have been in the western part of the basin. As was the unnamed depression. So 6 of 9 (or if you don't count Alex 6 of 8) cyclones this year have been west of 70W.

The western part of the basin has been favorable, as expected

Two hurricanes which barely attained that status and struggled most of their lives and 3 slop storms that were barely TS doesn't seem very favorable to me. It was just favorable enough to get TCs but as far as intensifying not so much. That is technically what I am saying. Storms in the past that reached the Gulf of Mexico during this time of year would always blow up given the time Hermine had over open water. Of course there are exceptions to this in the record books but for the most part storms that spend as much time over the water as Hermine did in the G.O.M tend to get their acts together quickly. I am no MET though so it is just my opinion. I judge favorable by quality over quantity.

[Steve]

No they wouldn't. We've dealt with way more depressions and tropical storms over the years. They just aren't as famous. Weather patterns have just been more active overall, and that's suppressed really strong development imho. Development areas have had smaller windows because of everything else going on. Alyono is 100% correct. As vast as high pressure has been at times in the Western Atlantic, we are all lucky that not everything else has been as favorable for big, powerful storms. Nobody really wants to see massive storms like Rita or Gilbert or Wilma this way. Also you can't argue legitimately by using your own scale but not changing the terms. You measure by classification. If you are talking about ACE, you need to say that and would still be wrong. But 6 of 9 (or 8) is fact.

[Ntxw]

Also you can't argue legitimately by using your own scale but not changing the terms. You measure by classification. If you are talking about ACE, you need to say that and would still be wrong. But 6 of 9 (or 8) is fact.

NOAA's main rankings of seasons based on their activity is ACE. Seasons are ranked by this metric and is a greater value in the meteorological community than numbers. An above average prediction is about 120% of normal, and below normal is 70%. An example of why the numbers game can be a flaw is an example of 2013 and 1998 for instance. 14 named storms and so was 1998. Number of storms is something more in tune for the general public to understand but often is more misleading than something more solid like ACE.

[Hammy]

5 of the 8 storms have been in the western part of the basin. As was the unnamed depression. So 6 of 9 (or if you don't count Alex 6 of 8) cyclones this year have been west of 70W.

The western part of the basin has been favorable, as expected

Two hurricanes which barely attained that status and struggled most of their lives and 3 slop storms that were barely TS doesn't seem very favorable to me. It was just favorable enough to get TCs but as far as intensifying not so much. That is technically what I am saying. Storms in the past that reached the Gulf of Mexico during this time of year would always blow up given the time Hermine had over open water. Of course there are exceptions to this in the record books but for the most part storms that spend as much time over the water as Hermine did in the G.O.M tend to get their acts together quickly. I am no MET though so it is just my opinion. I judge favorable by quality over quantity.

People keep referring to the "slop storms" earlier in the season but fail to realize, having one of those early in the season is not only normal, but on top of that, we had -three- of them--while on the average there is one storm by the end of June roughly twice out of every three years. That we had three in that time does in fact show that the western part of the basin is more favorable. And as for the hurricanes that "barely attained hurricane status" only did so because they ran into land.

[Steve]

Also you can't argue legitimately by using your own scale but not changing the terms. You measure by classification. If you are talking about ACE, you need to say that and would still be wrong. But 6 of 9 (or 8) is fact.

NOAA's main rankings of seasons based on their activity is ACE. Seasons are ranked by this metric and is a greater value in the meteorological community than numbers. An above average prediction is about 120% of normal, and below normal is 70%. An example of why the numbers game can be a flaw is an example of 2013 and 1998 for instance. 14 named storms and so was 1998. Number of storms is something more in tune for the general public to understand but often is more misleading than something more solid like ACE.

He was arguing a slightly different point. If you go back to the prior post, he challenged that the western basin was "supposed to be favorable but not so much..." Re-reading what he says in the second post, I don't completely disagree with his premise. But regardless, landfalls and number of landfalls usually matter regardless of what or where they are. You're probably not going to argue with the impacts of someone who lives in Cedar Key or Tallahassee by a system that generated, what, 3 ACE? It's real life in the Western Basin and it matters (usually). Hermine 1998 didn't matter whereas Frances did. Also, at the end of the day, did Gaston or whatever 94L does really matter all that much to anyone on this side of the world if they have half the season's ACE? You could make the argument that it matters because the heat was coming out of the tropics in a way that was less destructive to the Islands, North and Latin America. But that's different.