Atlantic Tropical Action 2013 - Part 2

[phil882]

 

 

 

That was the 18z run... 00z is much further south an into Mexico. I'll be posting some more detailed thoughts in a moment... it might be time now. 

[HurricaneJosh]

Well Technically

The 2002 Summer solstice was June 21st at 9:24am est  and the 2013  Summer solstice was June 21st at 1:04 am.

 

That means the record occurred 25 minutes ago!  Time to start celebrating the lameness!

 

Whoa, that's a cool way to think about it.  

[HurricaneJosh]

That was the 18z run... 00z is much further south an into Mexico. I'll be posting some more detailed thoughts in a moment... it might be time now. 

 

Oops, yeah, just saw that.  I got excited for a sec-- thought the 00Z was validating the 18Z.  Grrrr.

 

In the 00Z, it just seems to kinda die along the coast.

[Derecho!]

Oops, yeah, just saw that.  I got excited for a sec-- thought the 00Z was validating the 18Z.  Grrrr.

 

In the 00Z, it just seems to kinda die along the coast.

 

Well the 00Z does spend an incredible amount of time over water given how far south it hits Mexico, and it does drop to 982 mb.

[HurricaneJosh]

Well the 00Z does spend an incredible amount of time over water given how far south it hits Mexico, and it does drop to 982 mb.

 

Yeah, true.  And it looks like a smaller, tighter, more consolidated cyclone in this run as well-- not a big, loose gyre anymore.

[wxmx]

Oops, yeah, just saw that.  I got excited for a sec-- thought the 00Z was validating the 18Z.  Grrrr.

 

In the 00Z, it just seems to kinda die along the coast.

Models always do this in this part of the GOM, leaves a surface trough behind. Probably terrain induced.

[Derecho!]

Can't help but notice that the final Humberto recurve trough keeps getting weaker and weaker...

[Ed Lizard]

That wasn't a very exciting run, and does squat rain wise for Houston.  Ad maybe I'm looking at the wrong displays, I'm seeing a mid-high range TS at best.

 

 

The 18Z was the happy exception.

[wxtrackercody]

That wasn't a very exciting run, and does squat rain wise for Houston.  Ad maybe I'm looking at the wrong displays, I'm seeing a mid-high range TS at best.

 

 

The 18Z was the happy exception.

[HurricaneJosh]

It looks like a decent cyclone this run-- much smaller, much tighter-- no more loose-gyre stuff-- but d*mn, I wish one of these systems would pull away from the coast a little. This squished-at-the-bottom-of-the-Gulf act is just gettin' real old.

[phil882]

Better say hawt things-- or else.  

 

Oh there are a number of possible solutions... but lets not forget Nate (2011) which was an utter fail in the same region and possesses some similar characteristics (very slow motion, same lack of latitude gain... if you take the 00z GFS verbatim). Nate was the ultimate example of SST upwelling from hell, where it somehow managed to upwell 22 C SSTs from initial surface SSTs around 30C!!

 

The good news is that this synoptic pattern is completely different from Nate, which was a small TC that developed off a dangling frontal boundary from the trough merger of Lee. That pattern was characterized by record low precipitable water along the Gulf coast and the vast majority of the Gulf of Mexico. Additionally, the large size of Lee in the days previous already had produced widespread upwelling across a large portion of the Gulf of Mexico. The initial frontal boundary (which was still a very strong moisture gradient) made it into the souther Gulf of Mexico. The strong northerly flow produced by this had continued the upwelling process even before Nate became a TC. 

 

Nate initially started as a highly sheared storm, but soon the vertical wind shear decreased to near zero. However, by the time Nate encountered favorable upper level winds, the SSTs were already rapidly decreasing and storm couldn't take advantage of the favorable upper level environment. 

 

93L is different, because

 

1) The environment is very moist, and will only likely become more moist with time, 

2) There hasn't been any previous system in the GOM (TD#8 was weak and enough in the past to allow SSTs to recover)

3) The OHC environment this year in the BOC is more favorable than in 2011. Even if the same amount of upwelling occurs, the larger OHC value should prevent as much decrease in surface SSTs from occurring. 

 

The thing is though, I don't know how realistic the operational GFS's 00z solution is, since is accumulates the vorticity into one discrete maxima pretty early on. That seems unlikely given the strong vorticity maxima occurring on the other side of the Gulf of Tehuantepec. On the flip side, its looking pretty likely that this system will have a textbook favorable upper level pattern, as an upper level trough currently over the GOM gives way into a very large and meridional upper-level ridge. Again this is traditionally a gyre like evolution, and normally that means there is a bit more fighting between the different mesovorticies before one becomes dominant over the other. I think the 18z GFS is a more likely outcome due to this "spin-up time" that needs to take place in merging equal magnitude vorticity centers. However, there are exceptions to every rule, and very powerful TCs (with very small MWR... at least initially) have developed from gyre circulations (Opal and Wilma being the poster children).

 

So the short version... this is obviously not a done deal by any means (and thats not even accounting for the fact it needs to get far enough away from land!) I don't want to put hard numbers on it, but I favor the moderate-strong sloppy TS over a very strong and tightly wound Hurricane. 

[HurricaneJosh]

So the short version... this is obviously not a done deal by any means (and thats not even accounting for the fact it needs to get far enough away from land!) I don't want to put hard numbers on it, but I favor the moderate-strong sloppy TS over a very strong and tightly wound Hurricane. 

 

Thanks, Phil-- interesting write-up.  That was a good reminder Re: how large gyres can really tighten up (like Opal and Wilma).

[HurricaneJosh]

When you look at that crazy typhoon being modeled in the WPAC, it's pretty sad that we're all so excited over a couple of closed isobars at the bottom of the Gulf.

 

93L aside, the GFS continues to look pretty lame two weeks out.  If Humberto for some reason doesn't make it to 'cane status, and let's say 93L doesn't either, there's a great chance we'll get to October without a 'cane, given the MJO shift, more SAL, etc.

 

We're almost getting into weird territory at this point.

[phlwx]

When you look at that crazy typhoon being modeled in the WPAC, it's pretty sad that we're all so excited over a couple of closed isobars at the bottom of the Gulf.

 

93L aside, the GFS continues to look pretty lame two weeks out.  If Humberto for some reason doesn't make it to 'cane status, and let's say 93L doesn't either, there's a great chance we'll get to October without a 'cane, given the MJO shift, more SAL, etc.

 

We're almost getting into weird territory at this point.

 

at least the "no cane into October" thought can go out the window.

[Ed Lizard]

Does it landfall like that?

 

[wxmx]

Does it landfall like that?

 

 

Yes, but remember, in this region it always degenerates a cyclone into a surface trough at landfall. It's difficult to assess if the weakening is real or just an artifact of land interaction around this area.

[Ed Lizard]

Yes, but remember, in this region it always degenerates a cyclone into a surface trough at landfall. It's difficult to assess if the weakening is real or just an artifact of land interaction around this area.

Not just land interaction, it'd appear.  Multiple runs.  Lame landfall, no rain IMBY.

 

 

[jconsor]

Given that the GFS is showing a small, compact TC, coarse resolution model images are close to useless.

 

The full-resolution images (http://www.tropicaltidbits.com/analysis/models/gfsfull/)

show weakening within 25 miles of the shore, but keep 93L quite strong until then.

 

[Superstorm93]

93L is making a nice first "landfall" on the Yucatan this morning. Should be interesting to see how it does in the BOC under relatively favorable conditions. 

 

By the way, it almost looks like a normal hurricane season

 

 

 

[EasternUSWX]

These things always try to look good right as they make landfall over the Yucatan.

 

[Chaser25973]

When you look at that crazy typhoon being modeled in the WPAC, it's pretty sad that we're all so excited over a couple of closed isobars at the bottom of the Gulf.

 

93L aside, the GFS continues to look pretty lame two weeks out.  If Humberto for some reason doesn't make it to 'cane status, and let's say 93L doesn't either, there's a great chance we'll get to October without a 'cane, given the MJO shift, more SAL, etc.

 

We're almost getting into weird territory at this point.

 

http://fox8.com/2013/09/11/hurricane-humberto-ruins-shot-at-record/

 

 

Hurricane Humberto Ruins Shot at Record

 

Sorry, Josh...

[Ed Lizard]

FIM-9 has good resolution for a global.  High end TS for near/just South of Tampico.

 

 

 

I don't see much reliable guidance coming up near the border or raining in MBY like the 18Z GFS was doing.

 

I'll miss the rain, I'm feeling sadly semi-confident in the track, but intensity is harder to predict, and after 2013 so far, if it does turn out to be a 70 knot Cat 1 somewhere either side of Tampico, I can see sudden travel arrangements from LAX being made.  The video as consolation prize, beggars can't be choosers.

 

Eye candy w/ some -80ºC tops.  Attachment, not hotlink, for posterity and warm nostalgia.

[bluewave]

http://fox8.com/2013/09/11/hurricane-humberto-ruins-shot-at-record/

 

 

Hurricane Humberto Ruins Shot at Record

 

Sorry, Josh...

 

But we did get the satellite record for a non El Nino summer beating 2001.

 

 

 

 

 

 

[Ed Lizard]

We'll break the record next year!

[CoastalWx]

When you look at that crazy typhoon being modeled in the WPAC, it's pretty sad that we're all so excited over a couple of closed isobars at the bottom of the Gulf.

 

93L aside, the GFS continues to look pretty lame two weeks out.  If Humberto for some reason doesn't make it to 'cane status, and let's say 93L doesn't either, there's a great chance we'll get to October without a 'cane, given the MJO shift, more SAL, etc.

 

We're almost getting into weird territory at this point.

 

The western carb will save you.

[eurojosh]

The western carb will save you.

 

You didn't hear?  This hurricane season is on a no-carb diet!

[Ed Lizard]

Big bowl of cold oatmeal bottom of the BoC through 3 days on GFS.

[GaWx]

93L aside, the GFS continues to look pretty lame two weeks out.  If Humberto for some reason doesn't make it to 'cane status, and let's say 93L doesn't either, there's a great chance we'll get to October without a 'cane, given the MJO shift, more SAL, etc.

 

 

Josh/others,

 Yes, we left the very favorable strong MJO phase 1-2, which is hard to beat per climo though it underproduced this time. The MJO is now within the circle and is projected to remain in there for much of the next two weeks. However, things are not currently unfavorable MJOwise. Here's why. I did an analysis of the number of TC geneses since 1995 in September for each MJO phase and came up with these overall % chances for genesis per day:

 

Phase 1: 24% (Ivan of 2004)

Phase 2: 17% (Ike of 2008 and Jeanne of 2004)

Phase 3: 6%

Phase 4: 16%

Phase 5: 8% (Humberto of 2007)

Phase 6: 6%

Phase 7: 14%

Phase 8: 15%

In Circle: 21% (Rita of 2005, Isabel of 2003, Lili of 2002, Floyd of 1999, Georges of 1998, Opal of 1995)

 

ALL        16%

 

 

- Being within the circle in Sep. since 1995 has actually been more conducive than average with 21% per day (vs. 16% per day overall) unlike in August when it was only 10%/lower than Aug. average.

- Surprisingly, phase 3 had only a 6% daily genesis rate, tied for the bottom in Sep.

- The MJO having gone into the circle is actually much better climowise in SEP since 1995 than if it had gone into phases 3-8 (see above stats).

- All but one of the CONUS H hits and all of the major CONUS H hits from Sep. geneses since 1995 were from geneses during phase 1, phase 2 , or within the circle.

- Within circle US H hitting SEP TC formation dates since 1995: Rita 9/17, Isabel 9/6, Lili 9/21, Floyd 9/7, Georges 9/15, Opal 9/27

- Clarification: There have been many more days within the circle vs. any one of phases 1-8. So, that's a big reason there were a whopping six geneses that lead to later H hits on the US. However, even after taking the # of days into account (i.e. "normalization"), within the circle was more conducive than average (21%/day vs. overall avg. of only 16%/day). Also, the # of days for phases 3-8, combined, were about the same as the # of days within the circle. Yet, there were six US H hits from within the circle vs. only one hit from phases 3-8, combined!

 

Edit:  Aside: The Euro ensemble mean did far better than the GEFS mean for this recent strong phase 1-2 peak though it was a little too strong. Therefore, I'd pay more attention to the Euro in the near future for the MJO.

[Superstorm93]

12z GFS has a sloppy mess in the BOC that really never gets itself together (it definitely isn't the 976mb ghost hurricane of previous runs)

 

93L looks...interesting over Belize/Yucatan 

 

[wxmx]

Feeling pessimistic about 93L...almost all models are now south of Tampico