ATL HANNA: Extratropical - Discussion

[NEXRAD]

If I were to look at the WV loop I would say Hanna should go right up the trough edge and out to sea. The High that is preventing that doesn't really show on WV.

I was honestly thinking this, too, watching the IRWV this morning, but didn't want to mention anything seemingly too radical.

- Jay

[KWT]

I wonder what role there is to be played if the the center has relocated, because there is some pretty good spin near the northern deep convection probably a degree north of where it was located before.

[NEXRAD]

I wonder what role there is to be played if the the center has relocated, because there is some pretty good spin near the northern deep convection probably a degree north of where it was located before.

Agreed; I'm pinning that more northern circulation near 21.7N, 71.4W.

- Jay

[AZRainman]

Easier to visually approximate Hanna's current LLC with a full size image.

[Aristotle]

Me thinks Hanna and Ike are headed for a rather intense relationship. A smashing one to be sure!

[DESTRUCTION5]

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

Looks like she is finally on the move..NW jog has commenced...

[BensonTCwatcher]

I am watching the ULL ( to the N of Hanna) to be pushed out N and E the tough and high pressure over the upper midwest is the key. The ridge is building west and that will move Hanna. The ULL to the NW which may be forming will impart shear if it does not retrograde, which I think it is if you look over the GOM you can see the ridge there backing SW. I don't see any change in track yet, just seeing what happens aloft affecting development.

[AZRainman]

Me thinks Hanna and Ike are headed for a rather intense relationship. A smashing one to be sure!

Fujiwhara effect

When the cyclones approach each other, their centers will begin orbiting cyclonically about a point between the two systems. The two vortices will be attracted to each other, and eventually spiral into the center point and merge. When the two vortices are of unequal size, the larger vortex will tend to dominate the interaction, and the smaller vortex will orbit around it.

The effect is often mentioned in relation to the motion of tropical cyclones, although the final merging of the two storms is uncommon. The effect becomes pronounced in these storms when they approach within about 1,450 km (900 mi) of each other and are at tropical storm strength or stronger.

[NEXRAD]

It'd be wild to see a Fujiwara Effect commence, and would no-doubt turn the models sideways.

- Jay

[AZRainman]

It'd be wild to see a Fujiwara Effect commence, and would no-doubt turn the models sideways.

- Jay

Yeah, will be an observational treat. I doubt the models are really configured for it, since there is so little data in the past to correlate from and will be like a lottery of landfall guessing.

[BensonTCwatcher]

Yeah a real curve ball guidance-wise. Yoda says "Unclear the future is" a lot of complexity in this setup now much less a Fujiwhara

[bob rulz]

A fujiwhara would certainly send this season over-the-top in terms of unpredictability.

[gtsmith]

just did a rough measure in google earth and they are about 1350 miles apart....hmmmm

[KWT]

Ike probabnly still 36-48hrs away from there being any threat of major interaction and thats providing Hanna stalls for that amount of time.

However Hanna is a big system so who knows.

Sat loops do really strongly suggest Hanna has relocated but recon will have to confirm everything firstly.

[Sanibel]

Yes, I was pointing this out last night. Hanna is the bigger, but Ike might be the stronger. If Ike hits Hanna at the same latitude Fujiwhara would dictate Ike to wheel up counterclockwise and north around Hanna which is contrary to guidance. I would surmise that with the High strongly above Ike the Fujiwhara result would be Hanna going more west and Ike rising up in latitude. Since this doesn't compute with the estimated tracks I would guess that Fujiwhara would translate into Ike kicking Hanna out of the way faster.

[chris_fit]

I'm actually seeing a drift just South of due West at around 21.7N and 71.8W

[Chacor]

HANNA HAS BECOME A LARGE TROPICAL CYCLONE. TROPICAL STORM FORCE
WINDS EXTEND OUTWARD UP TO 290 MILES...465 KM...MAINLY TO THE NORTH
OF THE CENTER.

That's a... large storm.

[cpdaman]

AT 1100 AM AST...1500Z...THE CENTER OF TROPICAL STORM HANNA WAS
LOCATED NEAR LATITUDE 20.6 NORTH...LONGITUDE 71.8 WEST OR ABOUT 95
MILES...155 KM...EAST-SOUTHEAST OF GREAT INAGUA ISLAND AND ABOUT 75
MILES...125 KM...SOUTHWEST OF GRAND TURK ISLAND.

HANNA IS MOVING TOWARD THE NORTH NEAR 6 MPH...9 KM/HR. A TURN TO
THE NORTHWEST WITH AN INCREASE IN FORWARD SPEED IS EXPECTED OVER
THE NEXT 24 HOURS. ON THE FORECAST TRACK...THE CENTER OF HANNA
SHOULD BE MOVING THROUGH OR JUST EAST OF THE CENTRAL AND
NORTHWESTERN BAHAMAS OVER THE NEXT COUPLE OF DAYS.

[BensonTCwatcher]

Let's hope that translates to slow to strenghten while moving quickly forward (if it ever starts)

EDIT: Oops advisory out a lttle early, looks like it's moving (above 5 mph is more than a drift I guess)

[gatorcane]

Florida out of the cone and breathing a sigh of relief....