ATL HANNA: Extratropical - Discussion

[AdamFirst]

I can't tell of any sort of clear heading for Hanna. Visible makes it look stationary but IR makes it look like it's drifting ESE...

[Myersgirl]

Is the stall a prelude for a direction change NW?

[KWT]

The reason it looks like it heading ESE is the shear is probably ramping up again.

This will probably mean Hanna will weaken a little in the short term but longer term I'd watch for the shear to ease off within the next 36hrs and when that happens Hanna will go bang, I'm thinking landfall around 105-115mph range but who knows it reminds me somewhat of hurricane Gracie.

[cpdaman]

looking "rounder"

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

lets hope nobody decides to peak thru

(and i just saw the track and forecast for td9 as well and i feel ill, really and truly ill w a dash of adrenaline)

[Sanibel]

Hanna briefly had a white IR signature in its coldest cloud tops which is off the charts.

[Hurricane Mac]

Why did they issue that as a special statement instead of just waiting for the 5pm advisory?

That was released by the NWS office in Miami, not the NHC

Aren't they in the same building on the FIU campus?

Yes they are, but on different ends of the building.

[txwatcher91]

Question here, would stronger storm mean more north or more south than forecast? I would assume it would mean more north, and the concerning thing is the GFS shows pressure in the 980 range at peak intensity which is VERY unusual for a global to do unless conditions are very favorable. Anyone agree and think a Cat 3 is fairly possible?

[NEXRAD]

There's still considerable northerly shear impacting the system, generally around 20 to 30 knots. This will cap any quick intensification in the nearterm. Based on reconaissance reports, Hanna's 5PM intensity will be set to between 65 and 75 knots. If the system begins to move NW during the next 24 hours, then it will be encountering increasingly powerful shear, which would not favor the system retaining hurricane intensity. For Hanna to continue as a hurricane, the system will need to stay within a fairly limited area of lesser shear that is present across the Turks and Caicos through the Srn Bahamas (e.g., Great Inagua to Andros island) or nearer Cuba's NE coast.

The strong northerly flow looks like it'll let up between Tuesday afternoon and Wednesday afternoon depending on what guidance you like.

- Jay

[deltadog03]

MAX FL TEMP 24 C, 299 / 14NM
GREATLY IMPROVED RADAR BANDING IN CENTER

Thats quite concerning.....The centers are now only 14nm apart...That WAS 42nm earlier this morning.....Also, radar banding getting better...She may blow up when shear dies off.

[KWT]

txwatcher91, a cat-3 certainly is possible over the gulf stream if the shear eases off when predicted, given its probably already a solid cat-1 and given its been constantly preoducing pretty insane convective bursts I wouldn't rule out by any means, indeed I'm thinking of aming a call for a major hurricane but I'm going to hold back for now at 95kts.

Nexrad, yep probably got another 24-3hrs of Gustav's outflow cuasing issues then that ceases really to be too much of an issue.

[Myersgirl]

It is unfortunate that the good news this year is: the proceeding hurricane is inhibiting the development of the next in line

[cpdaman]

looking at this shear set up

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

it is surprising she had found herself a little "hiding spot" from the higher shear

not so sure how long this will last.....i think forecast for shear drops off after 48 hours ....but till then not sure how long her "relatively" lower shear spot will last..........

[BigA]

Is the majority of the northerly shear caused by Gustav outflow right now?

[Steagle]

The reason it looks like it heading ESE is the shear is probably ramping up again.

This will probably mean Hanna will weaken a little in the short term but longer term I'd watch for the shear to ease off within the next 36hrs and when that happens Hanna will go bang, I'm thinking landfall around 105-115mph range but who knows it reminds me somewhat of hurricane Gracie.

Thanks KWT..this accounts for the change in conditions here in the North. D.R

[storms in NC]

MAX FL TEMP 24 C, 299 / 14NM
GREATLY IMPROVED RADAR BANDING IN CENTER

Thats quite concerning.....The centers are now only 14nm apart...That WAS 42nm earlier this morning.....Also, radar banding getting better...She may blow up when shear dies off.

As she moves up the coast she will keep building till she hits land

[Chigger_Lopez]

UKMET still into S. Florida and NGFDL is in Melbourne area now. Arent the CMC and Euro showing somewhere in central or south florida as well? Please advise. . .

[NEXRAD]

Is the majority of the northerly shear caused by Gustav outflow right now?

It's caused by a combination of a potent upper level ridge situated over the Ern Gulf of Mexico and the trough moving north of Hanna. These two features are channeling air aloft through a tight upper level pressure gradient that stretches roughly from the Kentucky/Tennessee area SE to northeast of the Bahamas. Thereafter, the flow diverges aloft over Hanna, which is actually helping the storm maintain deep convection, though it is also inhibiting much convective organization well north of the center. Gustav's outflow is being channeled about these upper level features, and no doubt Gustav is also contributing to the pressure gradients.

- Jay

[storms in NC]

Think Fl need to keep a eye on her but landfall is not called for in Fl at this time

[cpdaman]

There's still considerable northerly shear impacting the system, generally around 20 to 30 knots. This will cap any quick intensification in the nearterm. Based on reconaissance reports, Hanna's 5PM intensity will be set to between 65 and 75 knots. If the system begins to move NW during the next 24 hours, then it will be encountering increasingly powerful shear, which would not favor the system retaining hurricane intensity. For Hanna to continue as a hurricane, the system will need to stay within a fairly limited area of lesser shear that is present across the Turks and Caicos through the Srn Bahamas (e.g., Great Inagua to Andros island) or nearer Cuba's NE coast.

The strong northerly flow looks like it'll let up between Tuesday afternoon and Wednesday afternoon depending on what guidance you like.

- Jay

exactly and is it me or does the shear "plume" looking to BEGIN to come at her now from a bit more of a 315 degree angle as opposed to 330- that she has been seeing.

[El Nino]

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

982.6 and not in the center. Sub980 ?