Major Hurricane Irene live tracking

[Amped]

Never mind you can see the center pretty well. 16N 59.5W

[janetjanet998]

you can clrearly see the large MLC and signs of the smaller LLC too more SW

[LakeEffectKing]

HAHAHA - so true. oh man. August is such a weird month. I mean ...it's thick of summer out there but in so little time it's a completely different world.

Actually, I'm not seeing really much to unusual about this kind of spread in the guidance for D5+ I will be honest though and say that I do see some synoptic reason supporting the western cluster. We'll see.

As you know, John, we can all present sound reasoned methodology for a forecast...and still have it go belly up!

[CUmet]

Perhaps, but "small circulation" and "diffused" are anti-corollary terms. I think I get what you meant though - even though there is was a small circulation identified, it exists inside a much larger cyclonic circulation.

THAT I completely agree with!

In fact, I noticed that a ring of convection propagated away from the overall axis, and as it did - and I believe "scoured" SAL away - we immediately saw a TC response in the core. Fascinating really ....

The rest going forward - I think there is some possibility that this ends up S of Cuba.

What Phil was saying is that the "smallness" of the circulation is really an illusion...an artifact of the coordinate system we're evaluating it on. It's only small in the earth-relative frame because the strength of the circulation is barely enough to overcome the storm motion, but the storm-relative circulation is in fact quite large. For example, the impressive 50+ kt flight-level winds were found over 150+ km from the VDM center.

There are times where indeed there is a small-scale vortex within a larger envelope of vorticity, but the broadness of the storm-relative wind profile suggests otherwise in this case.

[Typhoon Tip]

As you know, John, we can all present sound reasoned methodology for a forecast...and still have it go belly up!

TC forecasting is an enigma to me - and to most others I am sure. I've seen systems cut straight through ridges, which seems to defy conventional wisdom; yet, other systems obey the classical physical model - and even in retrospect it is less clear at times why a given system did what it should not have done.

Got to take my chances with a transient +NAO -related ridge response in the 35N latitude will assist in a western bias though. We'll see.

[Typhoon Tip]

What Phil was saying is that the "smallness" of the circulation is really an illusion...an artifact of the coordinate system we're evaluating it on. It's only small in the earth-relative frame because the strength of the circulation is barely enough to overcome the storm motion, but the storm-relative circulation is in fact quite large. For example, the impressive 50+ kt flight-level winds were found over 150+ km from the VDM center.

There are times where indeed there is a small-scale vortex within a larger envelope of vorticity, but the broadness of the storm-relative wind profile suggests otherwise in this case.

Absolutely, storm relative strength compared to the overall circulation is precisely what I meant as a support of his statement, too - yes.

I do think it is plausible, however, that the earlier propagating away of deep convection made an internal "cocoon" environment where that SAL band was less inhibitory. The new convection closer in went nuts almost immediately, and the llv circulation is now getting "pulled" into the region of deeper UVM. That's my take on this -

[BlizzardWarning]

To me it looks like the circulations has tugged significantly north on IR. Mid-level C looks to be around 16.5N, 59W. Looks to me like this is heading straight for Puerto Rico.

http://www.ssd.noaa.gov/goes/flt/t2/loop-rb.html

[Dunkman]

To me it looks like the circulations has tugged significantly north on IR. Mid-level C looks to be around 16.5N, 59W. Looks to me like this is heading straight for Puerto Rico.

http://www.ssd.noaa....t2/loop-rb.html

I wouldn't say it's headed straight for PR just yet, but the NHC did hint at such a possibility (I'm assuming the LLC moving under the convection) with:

A HURRICANE WATCH COULD BE REQUIRED FOR PUERTO RICO TOMORROW IF THERE IS A SIGNIFICANT NORTHWARD ADJUSTMENT TO THE TRACK FORECAST.

[OHweather]

In the interest of saving space, I will not post my whole write-up here but will link to it for anyone interested. It can be viewed here:

http://impactweather.wordpress.com/2011/08/20/tropical-storm-irene/

Essentially, Irene is not very well organized right now with centers that are not aligned. However, expansive outflow and what looks to be low shear over the eastern Caribbean given an upper level anti-cyclone over Irene and relatively weak (for the region) low level easterlies in place, along with good outflow provided by a belt of westerlies to the north of Irene. Irene has 36-48 hours before likely impact with Hispaniola and that may be just enough to get a minimal Cat 1 before interaction with the big island.

Past the islands the environment will favor re-intensification with the upper level anti-cyclone remaining over Irene, however how much intensity/organization it looses over the islands of Hispaniola and possibly Cuba remains to be seen.

Ridging will hold fairly strong north of Irene through day 2, keeping it on a WNW course towards Hispaniola. Troughs to the north of Irene will gradually weaken ridging north of the system thereafter resulting in a slower forward motion and gradual right turn. However, no trough over the next several days appears as though it will be strong enough to completely recurve Irene, which is why a track west of Florida into the eastern Gulf along with a relatively slow right turn appears to be possible.

[DopplerWx]

To me it looks like the circulations has tugged significantly north on IR. Mid-level C looks to be around 16.5N, 59W. Looks to me like this is heading straight for Puerto Rico.

http://www.ssd.noaa....t2/loop-rb.html

looks like some nice development around the possible center in those later frames.

[hm8]

How did the 00z gfs look?

Just rolling out now...

[Floydbuster]

How did the 00z gfs look?

So far out to 57 hrs....just scraping south coast of Haiti.

[DoctorMu]

The convection seems to be interacting with the outer band on the north side, so it may not be indicative of mean storm path movement (which still looks barely north of west). The south side still remains with far less convection. Some dry air had wrapped around the wave 2 days ago and into the south side. It's night in a very large TS that is just getting organized. A path toward Jamaica and western Cuba still seems possible.

[Natester]

Oh guys, look at this.

[WeSuck]

New GFS looks to have Irene crossing eastern Cuba at 84 hours

[hm8]

00z GFS creepin' slowly along Cuba...north of the 18z run

[Thunder Road]

Is it just me or did the 00z GFS initialize Irene a bit too far south? Looks like it has it over Barbados or thereabouts.

I'm kind-of a tropics noob though, so maybe not.

Anyway, passing over central Cuba at hr 99

[BethesdaWX]

Oh guys, look at this.

Definitely can see significant inflow there, also looks like drier air to the S & SW of the Center there? Well defined now but seems to be pulling dry air.

[Typhoon Tip]

00z GFS creepin' slowly along Cuba...north of the 18z run

Looks like it's trying to bring it up the EC actually... interesting

[Cheeznado]

The GFS has gone back east again, headed for Miami

[Natester]

Definitely can see significant inflow there, also looks like drier air to the S & SW of the Center there? Well defined now but seems to be pulling dry air.

Actually, Irene injested it's center into the convection.

[WeSuck]

988 mb SE of Miami at 114 hours...east coast again?

[Marion_NC_WX]

Storm being trapped over South Florida at 126...it will be interesting to see where this goes after the two ridges begin to seperate.

[DoctorMu]

The GFS has gone back east again, headed for Miami

Yes -next Friday on the E coast of FL and up to NC Sunday and up the eastern seaboard.

[WeSuck]

Storm being trapped over South Florida at 126...it will be interesting to see where this goes after the two ridges begin to seperate.

Interesting...Looks to be On or just east of Miami at 126 hours at 983 mb. There is a slight weakness between the ridges but it may not be enough to pull Irene up the coast.

[BethesdaWX]

Actually, Irene injested it's center into the convection.

It definitely has.....not my point, but fair enough.

[OHweather]

12z GFS at 120 hours:

0z GFS at 108 hours:

On the 0z run, the whole pattern seems to be a touch more amplified...with a slightly stronger trough over Alaska and slightly larger ridge over the Davis Strait. There is a closed low on the 0z run off the southern tip of Greenland which may also be contributing to the shortwave over the Great Lakes being slightly slower and slightly deeper, resulting in a track slightly to the east (ridging can't build back west north of the system as fast if the shortwave is slower/deeper).

These small details along with the eventual size/intensity of Irene will dictate its track come Wednesday through the weekend. Given a small change in Alaska, Canada or Greenland can cause a change in where Irene may go there is obviously some uncertainty as to where the storm tracks down the road.

[BethesdaWX]

12z GFS at 120 hours:

0z GFS at 108 hours:

On the 0z run, the whole pattern seems to be a touch more amplified...with a slightly stronger trough over Alaska and slightly larger ridge over the Davis Strait. There is a closed low on the 0z run off the southern tip of Greenland which may also be contributing to the shortwave over the Great Lakes being slightly slower and slightly deeper, resulting in a track slightly to the east (ridging can't build back west north of the system as fast if the shortwave is slower/deeper).

These small details along with the eventual size/intensity of Irene will dictate its track come Wednesday through the weekend. Given a small change in Alaska, Canada or Greenland can cause a change in where Irene may go there is obviously some uncertainty as to where the storm tracks down the road.

I've noticed all summer the progged NAO pattern has very often been forecasted too positive on most scales within the ensemble mean...if this means anything I'm not 100% sure but my guess is the NAO will trend negative based on past history this summer.

[WeSuck]

And up the east coast she goes on the GFS. Just east of Richmond VA at 204 hr 991 mb. Verbatim, it would only take a bit more to keep Irene over water just east of Florida and become a real beast. However, it is one model run and means very little at this point in time.Next up...EURO!

[OHweather]

I've noticed all summer the progged NAO pattern has very often been forecasted too positive on most scales within the ensemble mean...if this means anything I'm not 100% sure but my guess is the NAO will trend negative based on past history this summer.

Per these graphics, that has been true a couple of times through the summer although it appears overall the ensemble NAO forecasts have not been bad this summer:

I will say this though, there is a good amount of spread after the initial well agreed upon dip negative as to whether the NAO will stay rather negative or bounce back to neutral as the European Ensembles showed 12z. The difference between the 12z GFS run and 0z GFS run shows what role that uncertainty will play down the road with Irene. Distance wise it's not a huge difference, but the 12z run was close to bringing Irene over the Gulf along with the 12z CMC and ECM ensembles, while the 0z run doesn't even make an attempt at doing that which would make a huge difference intensity wise.