ATL HANNA: Extratropical - Discussion

[AJC3]

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

I doubt it. What you generally see in this type of environment where you have a vigorous LLC in a moderately strong (15-20kt) sheared environment is that the convection blows up near or over the LLC, obscuring the center for a time before getting ripped away downshear. I suspect that's what we'll see in a few hours. Keep checking IR2 to see whether or not this will be the case.

[cpdaman]

O town i would say the western extent of it has moved a couple degrees but the center itself has just slightly moved about 3/4 degree, but the "digging" appearance the Se side of it (had this earlier today) dissapeared in the afternoon. I.E the WSW flow along the SE side slackened and appears to have turned more SSW Imo.

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

[cycloneye]

BREAKING NEWS=The Best Track ay 00:00 UTC increases the winds to 40kts.

AL, 08, 2008082900, , BEST, 0, 208N, 602W, 40, 1001, TS,

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/

[meteorologyman]

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.[/quote]

From what I understand I think Hanna will continue to explode with convection for at least an hour or 2. During day time heating humidty skyrockets, but as the sunsets the atmosphere begins to cool down. Which will bring cold updrafts to the center of circulation causing cold cloud tops. If the storm can keep warm temps and cool temps equallized it will continue to repeat the cycle which could cause rapid intensification as long as there is no shear involved, like with Hanna is experiencing shear, and unlike with Katrina. So because of ULL we all should be happy it won't be strong storm for some time

[canegrl04]

I can't remember ever seeing a sutuation like this in the Atlantic where you had the likelyhood of two hurricanes impacting the Gulf States in such a close period of time .Not a typical hurricane season this year

[AJC3]

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

No need to apologize. It does appear as if it's starting to nudge westward...hence why I said it was "Q-stationary" (quasi-stationary) earlier as opposed to being "stationary". There appeared to be an ever-so-slight drift westward, but not very significant - that may be changing a bit now.

Still, it's going to take some time for Hanna and the ULL to gain separation. NHC, in one of their last TCDs mentioned something on the order of there being "a fine line between favorable and unfavorable " which is quite true in this case. Check out the shear and divergence charts...

http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html
http://cimss.ssec.wisc.edu/tropic/real- ... g8dvg.html

Hanna is in an area of 15-20 knot upper tropospheric shear, but the shear is also highly divergent, which favors upward vertical motion, aiding convection. If a bit more separation comes to pass, particularly if Hanna can get to the NE of the ULL, shear will drop off and the pattern will become highly divergent, a much more favorable scenario for intensification.

[cpdaman]

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

From what I understand I think Hanna will continue to explode with convection for at least an hour or 2. During day time heating humidty skyrockets, but as the sunsets the atmosphere begins to cool down. Which will bring cold updrafts to the center of circulation causing cold cloud tops. If the storm can keep warm temps and cool temps equallized it will continue to repeat the cycle which could cause rapid intensification as long as there is no shear involved, like with Hanna is experiencing shear, and unlike with Katrina. So because of ULL we all should be happy it won't be strong storm for some time[/quote]

not convinced there is strong shear. there is good outflow over a decent amount of the right portion of the system, which goes to show you the shear does not have to move that much for this to be under very good venitlating conditions OR of course to come back and haunt hanna

that is why the intensity forecast is so difficult in the short term

[vacanechaser]

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

we have seen this with other systems this year... fay comes to mind.. the shear seems to lessen over night.. too many peopel here have been writing this off just because the shear was getting to it today... i get tired of it every year... just a few posts back someone wrote it off and now look.... same thing with gustav last night.. ohh its dead, drop the warnings...now look... same thing... they change, conditions change... and i have seen and been in systems sheared worse than this was today at landfall... as long as the llc is as vigerous as hanna's is, never write it off


Jesse V. Bass III
http://www.vastormphoto.com
Hurricane Intercept Research Team

[meteorologyman]

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

From what I understand I think Hanna will continue to explode with convection for at least an hour or 2. During day time heating humidty skyrockets, but as the sunsets the atmosphere begins to cool down. Which will bring cold updrafts to the center of circulation causing cold cloud tops. If the storm can keep warm temps and cool temps equallized it will continue to repeat the cycle which could cause rapid intensification as long as there is no shear involved, like with Hanna is experiencing shear, and unlike with Katrina. So because of ULL we all should be happy it won't be strong storm for some time

not convinced there is strong shear. there is good outflow over a decent amount of the right portion of the system, which goes to show you the shear does not have to move that much for this to be under very good venitlating conditions OR of course to come back and haunt hanna

that is why the intensity forecast is so difficult in the short term[/quote]

So are you saying I'm sort of on the right track with this, because I'm trying to understand how tropical cyclones work with everything, because I gathered all this from sattelite imagery ,not by reading books or searching online.

[Tampa Bay Hurricane]

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

I doubt it. What you generally see in this type of environment where you have a vigorous LLC in a moderately strong (15-20kt) sheared environment is that the convection blows up near or over the LLC, obscuring the center for a time before getting ripped away downshear. I suspect that's what we'll see in a few hours. Keep checking IR2 to see whether or not this will be the case.

Thank you for the correction! It will be interesting to watch this process!

[meteorologyman]

It would be cool if we can provide oiur own light to shine on Hanna and Gustav so we don't have to rely on Infrared ,but that would have to be 1 BIG LIGHT BULB

[Blown Away]

Examples of Hurricanes that made a loop and/or WSW approach to SFL:
Jeanne:

Betsy:

Andrew:

1947 Storm:

[O Town]

None of those are wussy storms either.
And all of them were last week in Aug. beginning Sept. except for Jeanne.

[stormchazer]

we have seen this with other systems this year... fay comes to mind.. the shear seems to lessen over night.. too many peopel here have been writing this off just because the shear was getting to it today... i get tired of it every year... just a few posts back someone wrote it off and now look.... same thing with gustav last night.. ohh its dead, drop the warnings...now look... same thing... they change, conditions change... and i have seen and been in systems sheared worse than this was today at landfall... as long as the llc is as vigerous as hanna's is, never write it off


Jesse V. Bass III
http://www.vastormphoto.com
Hurricane Intercept Research Team

Very true though I did post that after all the doomsday would it not be a trip if Gustav just "poofed". I had a disclaimer stating I did not think it would but you can inderstand people for hoping it would, especially if your on the North or western GoM.

I actually think its worse right now if Hanna stays weak for a while because she is less likely to move aggressively North if there is any weakness ahead of her.

[Blown Away]

If, BIG IF, Hanna comes to SFL, does she do a loop and/or move WSW towards SFL? I say a track similiar to the 1947 storm, not same intensity, because the 1947 storm made it near 27N before moving WSW back to SFL. I realize dissipation, out to sea, and Carolinas are just as likely.

[AtlanticWind]

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

Upper low moving clearly west now , should be out of the way fairly soon.

[Bocadude85]

If, BIG IF, Hanna comes to SFL, does she do a loop and/or move WSW towards SFL? I say a track similiar to the 1947 storm, not same intensity, because the 1947 storm made it near 27N before moving WSW back to SFL. I realize dissipation, out to sea, and Carolinas are just as likely.

I was thinking a combo between Jeanne and the 1947 storm..leaning more towards the 1947 track though.. maybe with jeannes intensity

[Vortex]

00Z runs wil start rolling in shortly..should be interesting.

[gatorcane]

this is some of the most impressive DEEP convection I have seen in the Atlantic basin in quite sometime

The thought keeps crossing my mind that maybe Hanna will be the more powerful of the duo --- hmmm

[Bocadude85]

this is some of the most impressive DEEP convection I have seen in the Atlantic basin in quite sometime

yea gator she looks a lot better then she did a few hours ago