ATL HANNA: Extratropical - Discussion

[Patrick99]

x-y-no and NEXRAD thanks for the response on the high..

Next question. I see some deep-layer ridging building in from the north on this WV loop heading down the EC of the CONUS.

Am I seeing this right and could this not steer Hanna on the left side of the NHC cone (a ECMWF/UKMET solution) towards peninsula FL, specifically Southern FL?

http://www.ssd.noaa.gov/goes/east/tatl/loop-wv.html

I could be wrong, but will high pressure build in between Gustav and Hanna as Gustav weakens and moves out or will Gustav leave a big weakness behind somewhat like a trough that will turn everything north as it attempts to move west

The Ohio high is moving off to the east which will allow Gus to proceed northward, as that high builds in from the west, Hanna will move west......timing is everything....does it hold for a FL hit? or does the next trof weaken it and allow Hanna track up the EC?....

Yeah, if it DOESN'T hold, I still just don't see the NHC's Savannah landfall. Not buying it. I'm sticking with NC or S. FL.

[gatorcane]

any chance it may just keep heading for Cuba before making a turn as many models just a couple of days ago suggested?

[captain east]

I still can't believe the ECMWF (Euro) model. It looks like it has nailed this sytem yet again. Go back and look at what is was showing 7+ days ago and you will be amazed how close its track and intensity forecast has been for Hanna -- which called for a large and strong system right where Hanna is at.

Gator, where does the Euro model predict where the landfall will be, I can't find a model of it.

[Trader Ron]

Idiots at CNN.com saying Hanna has formed in the 'Caribbean'

They're not the only ones. CNBC also said "Caribbean".

NHC: Hurricane Hanna forms in the Caribbean ..Fox news

[greels]

Idiots at CNN.com saying Hanna has formed in the 'Caribbean'

We like to pretend we're part of the Caribbean here in the Bahamas.

Stay safe there, my neighbors to the west....this hurricane is not pretty at all.

[tolakram]

reposition

[Grease Monkey]

Idiots at CNN.com saying Hanna has formed in the 'Caribbean'

We like to pretend we're part of the Caribbean here in the Bahamas.

I think it's better for business entertainment wise. Doesn't sound more interesting if they say Hanna just formed (and is a hurricane too after gustav hitting land) rather then say hanna continues to organize in the carribbean. It makes people think wow, what timing. Creates more drama.

[NEXRAD]

An eye-like signature is beginning to appear in various microwave imagery, but convective banding NW of Hanna's center isn't that impressive. Combined shear and outflow suppression to the system's NW is doubtlessly hindering the overall convective situation; the storm's deepest activity is very asymmetric.

For the overall future track, Hanna is poised to take and eventual turn, and it remains unclear to me exactly when that will happen. For the short-term (through at least Tuesday night) a deeper Hanna will likely persist along a general west track with some SW movements. Thereafter, the exact turn is more perplexing, and it will depend on the storm's intensity and on how the ridging to the east responds to the outbound trough and Hanna. It will also be important to monitor the ridges situated near and west of Florida and over the Ohio Valley. If either of these remain potent through the mid-week period, then look for a more west storm track with Hanna. Likewise, the weakening (or dissipation) of either ridge would influence the storm to move more north.

- Jay

[MortisFL]

well the NHC didn't shift the track much left at the 1pm advisory....but probably won't see anything significant until 5pmEST or later.

now its nail-biting time along FL's east coast to see what new model trends will be and if indeed the west shift starts happening as NEXRAD anticipates couuld.

I didnt realize the track changed at 1pm (2pm intermediate) advisories. 5-11-5-11

[gatorcane]

An eye-like signature is beginning to appear in various microwave imagery, but convective banding NW of Hanna's center isn't that impressive. Combined shear and outflow suppression to the system's NW is doubtlessly hindering the overall convective situation; the storm's deepest activity is very asymmetric.

For the overall future track, Hanna is poised to take and eventual turn, and it remains unclear to me exactly when that will happen. For the short-term (through at least Tuesday night) a deeper Hanna will likely persist along a general west track with some SW movements. Thereafter, the exact turn is more perplexing, and it will depend on the storm's intensity and on how the ridging to the east responds to the outbound trough and Hanna. It will also be important to monitor the ridges situated near and west of Florida and over the Ohio Valley. If either of these remain potent through the mid-week period, then look for a more west storm track with Hanna. Likewise, the weakening (or dissipation) of either ridge would influence the storm to move more north.

- Jay

Can you explain in more detail about how the intensity of Hanna will affect her track? In the short-term it appears a deeper Hanna will drive more W or SW due to steering currents in the mid-and upper-levels which are NE and N respectively, but in the long-term once Hanna bends to the WNW or NW how does a deep vs shallow system play out on track?

[AJC3]

Gang,

The track forecast doesn't change during an intermediate advisory, however NHC did not put out an intermediate...they put out a complete special advisory package. In the dicussion, they mentioned that they only tweaked the track, mainly due to the recon showing the center was indeed tucked down farther south into the deeper convection.

[WindRunner]

well the NHC didn't shift the track much left at the 1pm advisory....but probably won't see anything significant until 5pmEST or later.

now its nail-biting time along FL's east coast to see what new model trends will be and if indeed the west shift starts happening as NEXRAD anticipates couuld.

I didnt realize the track changed at 1pm (2pm intermediate) advisories. 5-11-5-11

It usually doesn't...but since Hanna was so much stronger than they had been estimating, they sent out a special advisory at 130pm EDT, with a fully update suite of products (including track).

[NEXRAD]

Hanna's movement really depends greatly on how the ridges set-up over the next couple of days. The Atlantic ridge will no-doubt be a substantial player in the storm's eventual evolution, and this particular ridge will affect deep-layer steering flow more than the other ridges, I suspect, based on how most guidance diminishes the E. Gulf and Ohio Valley ridges. (To be fair, some guidance suggests the Ohio Valley ridge will be merging with the Atlantic subtropical ridge.)

The storm's position as the ridge patterns change will be a factor, too. If Hanna ends up farther south, then the Atlantic ridge will have a greater potential to build NW of the storm, setting up a greater steering flow to guide the system generally towards Florida through Georgia. If Hanna stays relatively near the current latitude, however, or deepens more substantially, then this could hinder Atlantic ridging building north of the system. Such a pattern would favor a more right storm track, possibly towards the Carolinas. Note that these are not forecasts, but are some possibilities depending on what exact steering pattern manifests.

No matter what exactly occurs, Hanna is a possible threat for the Southeastern US from South Florida through the Carolinas, and everyone across these areas needs to monitor this storm's progress.

- Jay

[WindRunner]

...ON RECENTLY UPGRADED HURRICANE STORM HANNA...

Just goes to show you how busy they are down there right now...

[gatorcane]

Hanna is a large system:

[storms in NC]

What is see if this is me or not. You know meds do funny thing to you. But in this loop you can see it go south then bounces back up. Like she giving us a nod yes
http://www.ssd.noaa.gov/goes/flt/t2/loop-vis.html

[Trader Ron]

And look what's behind Hanna..

[cycloneye]

And look what's behind Hanna..

And behind and behind.......................

[captain east]

Hanna is a large system:

Like someone said before," This thing could eat Florida."

[Evil Jeremy]

I am not surprised that Hanna is now a hurricane. However, I am shocked that the Hurricane force winds extend 70 miles out from the center. That is a big wind field for a 75 MPH storm.