ATL HANNA: Extratropical - Discussion

[HURAKAN]

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

Convection developing over/very near the LLC.

[Weatherboy1]

it appears to me the ULL may finally be moving ever so slightly to the W, and there is a new plume of convection firing up on the E side of the surface LLC. We'll have to see if these trends continue overnight.

[O Town]

Good question FCI, inquiring minds want to know.
I have heard that a ULL can work its way down to the surface and actually become a tropical system, but what will happen when they merge together?

[cpdaman]

Good question FCI, inquiring minds want to know.
I have heard that a ULL can work its way down to the surface and actually become a tropical system, but what will happen when they merge together?

if they merge i will buy you a steak dinner

[O Town]

Good question FCI, inquiring minds want to know.
I have heard that a ULL can work its way down to the surface and actually become a tropical system, but what will happen when they merge together?

if they merge i will buy you a steak dinner

Yee Haw!!!! lol
I didn't say they would just asking what if..............

[tolakram]

Keep your eye on this page:

http://rammb.cira.colostate.edu/ramsdis ... opical.asp

Top left is the vis/ir2 (shortwave) floater without being screwed up by the new color scheme.

in fact this is a prime example of how bad the new scheme is:

[jaxfladude]

So Hanna is still with us..... ..............the season of the undead.......

[Tampa Bay Hurricane]

If the ULL sucked Hanna in, then the Upper Level Low would provide
massive instability and cold air aloft to cause an explosive blow
up of convection, and Hanna would provide the mid and low level
circulation to bring the winds to the surface and to feed the very
unstable Upper Level Low. You would have an explosive system
that would likely rapidly intensify. Before Hanna is sucked in, Hanna may
weaken due to shear, but once the low level and upper level lows stack
on each other, there would be explosive instability with the cold low
aloft and hot feed at the surface, and you are looking at a rapidly
intensifying Hanna. That is IF the ULL and Hanna COMBINE.
Hanna would very quickly reach hurricane status- only days after
being impacted by significant shear.

[jaxfladude]

If the ULL sucked Hanna in, then the Upper Level Low would provide
massive instability and cold air aloft to cause an explosive blow
up of convection, and Hanna would provide the mid and low level
circulation to bring the winds to the surface and to feed the very
unstable Upper Level Low. You would have an explosive system
that would likely rapidly intensify. Before Hanna is sucked in, Hanna may
weaken due to shear, but once the low level and upper level lows stack
on each other, there would be explosive instability with the cold low
aloft and hot feed at the surface, and you are looking at a rapidly
intensifying Hanna. That is IF the ULL and Hanna COMBINE.

If that occurs(not that is set in stone mind you) then would Hanna go polewards, nothwards away from the CONUS and the Bahamas...?????

[Tampa Bay Hurricane]

If the ULL sucked Hanna in, then the Upper Level Low would provide
massive instability and cold air aloft to cause an explosive blow
up of convection, and Hanna would provide the mid and low level
circulation to bring the winds to the surface and to feed the very
unstable Upper Level Low. You would have an explosive system
that would likely rapidly intensify. Before Hanna is sucked in, Hanna may
weaken due to shear, but once the low level and upper level lows stack
on each other, there would be explosive instability with the cold low
aloft and hot feed at the surface, and you are looking at a rapidly
intensifying Hanna. That is IF the ULL and Hanna COMBINE.

If that occurs(not that is set in stone mind you) then would Hanna go polewards, nothwards away from the CONUS and the Bahamas...?????

I'm afraid it would track westward under the ULL, the whole system track westward towards the Bahamas.
The ridge to the north is very potent, as evidenced by the extreme heat over FL peninsula the last
few days. That same ridge saves the peninsula of FL from Gustav, but a stronger Hanna would
ENHANCE the ridge and make a west track even more likely. To be honest, I am seeing a westward
trend with this system, and that has me very concerned even this far out. I don't want any tropical
systems nearing Bahamas/FL, but the ridge may not agree with me.

[wzrgirl1]

I was just reading the advisories on Andrew, and it seems so eerily similar in that Andrew was almost sheared to death with no clearly defined center only 4 days before it hit south florida.....i like to compare storms every once in a while to see if the synoptics are similar and although no two storms are exactly alike, they do sometimes have certain patterns that coincide. Again I am not saying this would even be remotely close to an Andrew, just stating what I read that's all.

[tolakram]

Two posts up:

I'm not so certain any of that is, um, ... I'd like to hear a pro-mets opinion on that.

[AJC3]

If anything the ULL to Hanna's NW (which appears to me to be pretty much Q-stationary) would impart a slight northward component of motion, not draw it toward it's center. It's main influence however continues to be fairly strong upper tropospheric shear.

The main steering mechanism is going to be weak mid level ridging which should temporarily build in behind the ejecting deep layer low well to the north.

IR2 imagery pretty clearly shows the now semi-exposed LLC still moving WNW to NW.

[jinftl]

I seem to recall alot of talk of a persistent trough off of the east coast the first part of this summer...now it seems like talk of a strong ridge is dominating. Is there any indication of whether this ridging will persist, and where the placement of the ridge is in relation to driving storms towards the U.S.? Didn't 2004 have a late season ridge dominate in the Atlantic as well?

[KWT]

Decent sized burst just blew up on the eastern side of the LLC, will no doubt get sheared off but its helping to keep this system alive.

[cpdaman]

Decent sized burst just blew up on the eastern side of the LLC, will no doubt get sheared off but its helping to keep this system alive.

as of 23:45 that burst now covers 90% of the LLC if not more

http://www.ssd.noaa.gov/goes/flt/t2/loop-ir2.html

also shear appears to be lessening, i don't see any tops blown off the convection to the SSW anymore, actually there is alot of convection to the south as well...crikey

[Tampa Bay Hurricane]

Thanks for the promet response! That clarifies the physics, yes Hanna
will not be sucked in, but impacted by shear and a north component.
Then a ridge follows.

[cycloneye]

The center is not seen in this recent image.

[Tampa Bay Hurricane]

Perhaps the ULL is starting to weaken based just on that image.

[O Town]

Im sorry but that ULL does not look stationary to me any longer.
It seems to be picking up speed and heading west.
Looks to have moved about 2 degrees west in the past 3 and 1/2 hours.

http://www.ssd.noaa.gov/goes/flt/t2/loop-wv.html
tick the lat./long. box