ATL HANNA: Extratropical - Discussion

[Matt-hurricanewatcher]

I'm impressed with Hati this year, they have been able to handle 3 cyclones with low death tolls to what they would of gotten even 3 or 4 years ago.

What is the chances for this to make landfall on the north coast of Hati?

[jaxfladude]

I would watch the real threat called "Ike"...not for my area but for whomever may end up with a nasty visit by Ike...Hanna is just too confusing for me right now...need to take a Hanna break for a awhile

[fasterdisaster]

I'm impressed with Hati this year, they have been able to handle 3 cyclones with low death tolls to what they would of gotten even 3 or 4 years ago.

Not really IMO. Jeanne was an exception and 2800 of the 3,000 deaths were in one town. 80 deaths from a minimal hurricane is bad for any country.

[AdamFirst]

It looks like it's going full blown east at this point...maybe out to sea?

[fasterdisaster]

It looks like it's going full blown east at this point...maybe out to sea?

It'd be nice but not a chance.

[CaneRx]

Hanna may be completing a loop, then get pushed NW. Could be good news for Fla.

[cpdaman]

It looks like it's going full blown east at this point...maybe out to sea?

last vdm confirmed east movement but it is about a 3mph drift EAST so i don't think so

the question i have is does anyone have any CANADIAN water vapor loop links

it should not be such a mystery when this closed low off New england will lift up and allow hanna to move, i want some clues as to what needs to move in canada to get this closed low to lift out

only using western atlantic and nw atlantic imagery is like trying to figure out a mystery but being half blind IMO

[fasterdisaster]

Hanna may be completing a loop, then get pushed NW. Could be good news for Fla.

Why? We'd be back at square one, really nothing would change.

[fasterdisaster]

It looks like it's going full blown east at this point...maybe out to sea?

last vdm confirmed east movement but it is about a 3mph drift EAST so i don't think so

Do you mean west 'cause east is what he said.

[NEXRAD]

It looks like it's going full blown east at this point...maybe out to sea?

From the last visible imagery of the day and some exposed low level clouds on IR, the circulation center seems to have moved relatively little. The convective eastward movement is being caused soley by shear, which the 21Z RUC/2 is showing as building up even stronger near and just NW of Hanna's center. The CIMSS 21Z vorticity analyses, 21Z RUC/2, and IRWV all suggest that an upper level "quasi" low may be developing north of Hanna, too, around 26N / 73W. The immediate future looks really bad for any tropical system, and Hanna is likely to remain a modest tropical storm at best under these conditions.

If the upper low can develop and become better defined, then the eventual E-ward passage of the trough combined with Atlantic ridging would likely bring the upper low towards the west. That could eventually cap some of the shear and maybe even help Hanna's outflow situation. As for timing, guidance suggests the trough remaining around and working against TS Hanna through at least Wednesday afternoon.

- Jay

[bahamaswx]

Deep convection has almost receded east of TCI. Good news for them!

[fci]

It looks like it's going full blown east at this point...maybe out to sea?

From the last visible imagery of the day and some exposed low level clouds on IR, the circulation center seems to have moved relatively little. The convective eastward movement is being caused soley by shear, which the 21Z RUC/2 is showing as building up even stronger near and just NW of Hanna's center. The CIMSS 21Z vorticity analyses, 21Z RUC/2, and IRWV all suggest that an upper level "quasi" low may be developing north of Hanna, too, around 26N / 73W. The immediate future looks really bad for any tropical system, and Hanna is likely to remain a modest tropical storm at best under these conditions.

If the upper low can develop and become better defined, then the eventual E-ward passage of the trough combined with Atlantic ridging would likely bring the upper low towards the west. That could eventually cap some of the shear and maybe even help Hanna's outflow situation. As for timing, guidance suggests the trough remaining around and working against TS Hanna through at least Wednesday afternoon.

- Jay

Jay:
If a ULL develops north of her; where does she go?

[KWT]

I'm pretty sure this is doing a long drawn out cyclonic loop but I want to see it start to gain some northerly motion soon before totally being in that boat.

Jay, yeah I noticed that as well I suspect this will remain sheared for another 24hrs yet...by which time it will probably be having a really tough time of it.

[NEXRAD]

FCI,

If an upper low develops north of Hanna, the ULL would likely steer west, eventually situating near Florida or perhaps even a bit more west depending on Hanna's depth and what happens with the Atlantic subtropical ridge. With Hanna being a tropical storm at present, I'd not expect the upper low to really impact the storm's movement too much, and since the feature hasn't really formed just yet, I'd prefer to not speculate too much on what might happen. Upper low + storm interactions are usually unique and dependent on many factors from what I've observed in the past.

- Jay

[cycloneye]

While Hanna decides what to do in terms of movement,Ike churns behind her closer and closer,and it will be interesting to see what interaction if any occurs between Hanna and Ike.

[Bocadude85]

is it true that the 18z gfs shows hanna moving wnw towards fl before turning north

[Weatherboy1]

It appears to me that the large cut off ULL up by New England may be preparing to leave another smaller ULL to its southwest, as forecast by the models. In other words, it looks like the forecasted trough split may be starting to occur. Hanna is a persistent little bugger and if she can survive this shear overnight, I think she'll be in a better position tomorrow. We'll see...

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

[NEXRAD]

is it true that the 18z gfs shows hanna moving wnw towards fl before turning north

The 18Z GFS takes Hanna mostly northwest, wobbles it WNW for a brief time E of Florida, and then resumes the NW movement.

- Jay

[cpdaman]

FCI,

If an upper low develops north of Hanna, the ULL would likely steer west, eventually situating near Florida or perhaps even a bit more west depending on Hanna's depth and what happens with the Atlantic subtropical ridge. With Hanna being a tropical storm at present, I'd not expect the upper low to really impact the storm's movement too much, and since the feature hasn't really formed just yet, I'd prefer to not speculate too much on what might happen. Upper low + storm interactions are usually unique and dependent on many factors from what I've observed in the past.

- Jay

ya the NHC mentioned this as a (cut off low forming to her west) in the 5 pm discussion, looks to me like it may be to her north (but either way) wouldn't this kind of protect the central bahamas if not S. florida as well (Not as much for central and n. fl though) might this also lead to hanna taking a "bigger loop"

[fci]

FCI,

If an upper low develops north of Hanna, the ULL would likely steer west, eventually situating near Florida or perhaps even a bit more west depending on Hanna's depth and what happens with the Atlantic subtropical ridge. With Hanna being a tropical storm at present, I'd not expect the upper low to really impact the storm's movement too much, and since the feature hasn't really formed just yet, I'd prefer to not speculate too much on what might happen. Upper low + storm interactions are usually unique and dependent on many factors from what I've observed in the past.

- Jay

Yes, and Hanna has proven to us, along with other storms; that the models and forecasters have a difficult time handling what ULL's do to movement.

I recall almost a "hands in the air, we don't know how to handle them" answer from a Pro Met or two on this subject.