ATL HANNA: Extratropical - Discussion

[Lowpressure]

http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=IPINECAY2

min pressure : 978.9 mb now the low is moving East from the station.

the wind has actually gone from SW to SE at Pine Cay, which swould suggest that the center was either north or northwest of them and is now somewhere between WSW and SW of the station.

AJC3 do you think by this you can tell ......this is weakening or just "fluctuating" or ?

http://adds.aviationweather.gov/satelli ... g&itype=ir

I would say fluctuating. It can not fight that much shear constantly on a strengthening pace, it has to pulse until the shear relaxes. I would not let my guard down at all. I think this will be a large player in about 72 hours plus.

[cpdaman]

TWC said Hanna is held in place by the ULL up to its north off the east coast. I guess it is pinned by the High and the ULL. When that cut-off Low forms I guess it will break up the blocking pattern and break Hanna out along the High.

so it's holding her down and giving her a steady shear beating which is increasing

http://cimss.ssec.wisc.edu/tropic/real- ... 8dlm6.html look at 6 hour trend

cimss shear trends tell the story

http://cimss.ssec.wisc.edu/tropic/real- ... shr-1.html

50-60 shear just to her NW yikes................ guess it depends on your definition of fluctuations/ weakening

i'm not leaving her for dead by any means.....just saying when recon gets in there tomorrow ....and this shear is present ......you will not see a hurricane IMO........but after 36 hours ......yes things will probably go up yet again

[ConvergenceZone]

I know that on the last Jeff Masters blog, he says that he wouldn't be suprised if this dropped back down to a tropical storm before it begins to move north west towards the east coast and intensify....You just wonder how much shear it can take before it finally starts to effect it.

[Blown Away]

Looks like SW drift again. Hanna will have to boogy to the SW to Great Inagua Island by 8am for the Ukmet to verify.

[Lowpressure]

What altitude is that 50-60 shear? It looks like very high outflow from Gus. If that is from Gus then shear tendnecy would be incorrect for a weakening hurricane over LA.

[bahamaswx]

Pressure was down to 1002mb here at 4pm. Up to 1006mb now, but most likely due to a SE drift rather than weakening.

[BensonTCwatcher]

that hear is from the outflow of gustav

note flow http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8dlm3.html

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8wvir.html

at at lower levels http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8ir.html

[BensonTCwatcher]

that shear map is 150-300mb layer mean minus 700-925mb layer mean

[Lowpressure]

that hear is from the outflow of gustav

note flow http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8dlm3.html

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8wvir.html

at at lower levels http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8ir.html

Thanks. So it logical that she may get beat down for a period and once shear relaxes be a big time player. I just did not see how tendency would increase from a dying GUS.

[BensonTCwatcher]

shear from gus's outflow will decrease and anticyclone will likely form over hanna. Note change in last 3 hrs

[Lowpressure]

shear from gus's outflow will decrease and anticyclone will likely form over hanna. Note change in last 3 hrs

Thanks for helping me with that.

[cpdaman]

shear from gus's outflow will decrease and anticyclone will likely form over hanna. Note change in last 3 hrs

are you saying to note the shear tendency increasing above hanna in the short term?

http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html

and this should reverse course as gustav weakens

[Blown Away]

If Hanna drifts around tomorrow she may be in Ike's 5 day error cone?

[bahamaswx]

Looks like SW drift again. Hanna will have to boogy to the SW to Great Inagua Island by 8am for the Ukmet to verify.

Follow the center, not the reds! Still slowing moving SE, and looks to be very close to Grand Turk, right under the recent blowup of convection.

[BensonTCwatcher]

you have to differentiate the shear FROM hanna vs affecting hanna. The tendency maps show the trend over the 3 hr period.

[BensonTCwatcher]

If you go here http://cimss.ssec.wisc.edu/tropic2/#

click on Hanna, turn on the IR, then turn on upper level winds.

Also the outflow on the N and NW side is diffuse and feathery. Not as if sheared to the SE

[cpdaman]

you have to differentiate the shear FROM hanna vs affecting hanna. The tendency maps show the trend over the 3 hr period.

thank you

[cpdaman]

62 mph sustained at turks and caicos in last 10 minutes

http://www.wunderground.com/weatherstat ... =IPINECAY2

wind has switched to ESE now (from sw earlier)

[blp]

Further SouthWest than 8PM.

HURRICANE HANNA FORECAST/ADVISORY NUMBER 21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
0300 UTC TUE SEP 02 2008

A HURRICANE WARNING REMAINS IN EFFECT FOR THE CENTRAL BAHAMAS...THE
SOUTHEASTERN BAHAMAS...AND THE TURKS AND CAICOS ISLANDS.

INTERESTS IN EASTERN CUBA...THE NORTHWEST BAHAMAS...AND THE FLORIDA
PENINSULA SHOULD MONITOR THE PROGRESS OF HANNA.

HURRICANE CENTER LOCATED NEAR 21.8N 72.5W AT 02/0300Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-SOUTHWEST OR 240 DEGREES AT 4 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 978 MB
MAX SUSTAINED WINDS 70 KT WITH GUSTS TO 85 KT.

[cpdaman]

track shifted slightly to the east

also interesting that the are now using the Pine key obseravation (in their disco) that have been linked here numerous times.........they forgot to use it last nite (when pine key was down to 995) and they had hanna at 997

they say in 24-36 hours should be able to intensify and they don't forecast weakening in the short term.......so looks like the fl is becoming less and less of a chance for this one to landfall.