Emily looking much better on SAT PICS.

[mike18xx]

probably a sign of real intensification probably. Thats what Dennis did and it then formed a true eye by the descending motion, not just by bands wrappind around a center

That's definately what we've been seeing lately... Plenty of wrapping; and a HUGE *eye*, most likely signifying the fact that it wasn't formed by the "descending motion", but by the wrapping around a center of circulation.

I don't know what "descending motion" you're talking about it; hurricane eyes form due to centrifuging; there may be some slight downward motion due to eddying with rapidly-rising convection in the eyewall (much as water near a stream-bank flows in reverse in places) -- but that isn't always so either:

Isabel: http://cimss.ssec.wisc.edu/tropic/archive/2003/storms/isabel/movies/isabel-eye.html.

[Lori]

latest sats also show that Eugene is destroying the anti-cyclone over Emily

Derek, Please explain

[Hurricane Cheese]

Alright, is it just me, or is she REALLY starting to look a lot better than just a few hours ago...!?!

[Matt-hurricanewatcher]

Emily is catching the outflow from Eugenes this morning. See Eugenes AntiCyclone/outflow is shearing Emily. Case in point this is the same thing that happen to 99L.
http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html

[mike18xx]

latest sats also show that Eugene is destroying the anti-cyclone over Emily

I'm not seeing any interaction between Emily and Eugene on stitched WV: http://cimss.ssec.wisc.edu/tropic/archive/2003/storms/isabel/movies/isabel-eye.html

These's a diurnal poof of Cooper Canyon monsoon stuff, but it's outflow looks pretty weak, and it veers away south and southwest over central Mexico (around Eugene's anti-cyclone aloft) rather than flow toward Emily.

[Derek Ortt]

actually,

there is a lot of descending motion in the eye. Simple mass continuity. There is divergence aloft at the eye wall, meaning over the center, there is convergence. At the top of a fluid, convergence means the air must go down. Very basic atmospheric dynamics using mass continuity.

The reason for there being no winds is due to the concept of solid body rotation where the winds are 0 at the center of a vortex

[Derek Ortt]

6 hours ago, the clouds were clealy defined in an anti-cyclonic pattern to the west of the storm. Now, those are gone and have been pushed east. Clear shear that the models yet again missed (they MUST improve their representation of TC's, as this interaction is always observed in reality, but not in the models)

[mike18xx]

There is divergence aloft at the eye wall, meaning over the center, there is convergence...

Please see the Isabel link I provided: Observe that there's no cirrus aloft spilling over into the interior; as rotational surface-inflow motion transitions to vertical convective motion in the eyewall, air parcels lose lateral velocity and are centripitally accelerated outward -- even in a developing storms without closed eyes, one may often observe an orbiting meso-cell spinning around with its blow-off nevertheless always heading outward.

The air "trapped" inside a closed eye is will have its own eddying motion (up at the edges, down in the center) driven by friction against the eyewall; this vertical eddying is comparatively weak, which is why cirrus veils existant at the time of formation can takes hours to clear away from closed eyes.

[Derek Ortt]

it is very straight forward. See the continuity equation. I'd recommend James Holton text book, it explains the concept of continuity much further

of course you dont see the cirrus, ITS DESCENDING

[mike18xx]

of course you dont see the cirrus, ITS DESCENDING

I am looking right at this: http://cimss.ssec.wisc.edu/tropic/archive/2003/storms/isabel/movies/isabel-eye.html, and what you're saying ought to be there isn't there. (If you set speed very high and set to rock, you can see clear-air exhaust waves radiating outward across the CDO cirrus canopy.)

There is nada going into that eye -- because it's a centrifuge-induced partial-vacuum, not a downdraft-cleared pocket.

[Derek Ortt]

will you please see the Holton book. It is well known that the eye contains subsidence. The lack of wind is due to solid body rotation. if there was not subsidence in the eye, there would be rain

[Patrick99]

It was cool to see that re-blossoming of convection...well, at least from my point of view on the other side of the Gulf...

[deltadog03]

how about this idea...i wonder if the outflow from TS eugene will shunt emily southward??

[Air Force Met]

I don't know what "descending motion" you're talking about it; hurricane eyes form due to centrifuging; there may be some slight downward motion due to eddying with rapidly-rising convection in the eyewall (much as water near a stream-bank flows in reverse in places) -- but that isn't always so either:

That is incorrect. There is a lot of descending motion inside an eye. That is why the temperatures in an eye are warmer than elsewhere...it's called adiabatic warming. That is why there is no cirrus...and why clouds clear out from the top to the bottom. The idea that it is "centrifuging" alone is a myth. It's not the rotation that pulls the clouds out...if that alone were true...stronger storms would have bigger eyes because of the centrifugal force invovled. The rotation actually works to help pull the air down as it centriguges out. What causes the clearness in the eye is primarily due to decending air...centrifuging is one of the mechanisms that help in creating that decending air...along with the convergence at the top of the storm. OVer the eye itself...even in the upper levels...there is cyclonic flow. I got examples in some old text books...but don't know of any links on the net to illustrate this. I'll look for them.

Here is something from the AOML (the hurricane research division) to help with the idea...
The eye forms as a result of the downward directed pressure gradient associated with the weakening and radial spreading of the tangential wind field with height (Smith, 1980) . Gradient wind balance above the boundary layer implies that the pressure on the vortex axis is less than that in the far environment at the same height by an amount that increases with the maximum tangential wind speed and the density. The decay and radial spread of the tangential wind speed with height and the decline in density with height implies that this pressure difference decreases with height so that the lowest perturbation pressures occur at low levels on the axis and <b> tend to drive subsidence along and near to the axis to form the eye. As the air subsides, it is compressed and warms relative to air at the same level outside the eye and thereby becomes locally buoyant. </b> This upward buoyancy approximately balances the downward directed pressure gradient so that the actual subsidence is produced by a small residual force.

http://www.aoml.noaa.gov/hrd/tcfaq/A11.html


My note: Warming air...because it is sinking...clears out the eye. The same is true concerning clear areas under ridges of high pressure. The sky is clear because the air is sinking and warms. There is much downward motion in the center of a hurricane...and the stronger the hurricane...the more downward motion there is. Air comes upward through the eyewall and spreads. Some goes out in the form of outflow, some goes inward. That part that goes inward eventually collides with the other air that is going inward and has no place to go but down.

[Air Force Met]

of course you dont see the cirrus, ITS DESCENDING

I am looking right at this: http://cimss.ssec.wisc.edu/tropic/archive/2003/storms/isabel/movies/isabel-eye.html, and what you're saying ought to be there isn't there. (If you set speed very high and set to rock, you can see clear-air exhaust waves radiating outward across the CDO cirrus canopy.)

There is nada going into that eye -- because it's a centrifuge-induced partial-vacuum, not a downdraft-cleared pocket.

Dude...read the AOML site...the guys who actually research WHY storms do things.

Matter of fact...here are some more links that prove what Derek (And I) are saying. I tell you what...we'll provide the research links that prove OUR point of view...and you provide the links that support YOUR point of view...that there is no downdraft in the eye (because if there IS a downdraft...adiabatic warming MUST take place according to the laws of physics and that creates a clearing). I'll be waiting for your resources.

"The intense convection in the eyewall region induces sinking motion and adiabatic warming inside the eye (Willoughby 1990, 1998). " http://www.rsmas.miami.edu/divs/mpo/Abo ... stract.pdf

"As tropical storms develop into hurricanes, they're characterized by upper tropospheric warming (the troposphere being
defined as that portion of the earth's atmosphere extending from the earth's surface to approximately 15km altitude)
as a result of adiabatic warming/compression of air as it subsides (sinks) within the storm center." http://amsu.ssec.wisc.edu/explanation.html

"It is found that a large portion of surface perturbation pressures is caused by the moist-adiabatic warming in the eyewall and the subsidence warming in the eye." http://ams.confex.com/ams/last2000/24Hu ... /12194.htm

"The winds are strongest around the eye wall, and the theory goes that these extremely strong winds act to throw air out of the eye, causing air from the upper levels to "fill in" <b> by subsiding, leading to the clear eye. As this air subsides, it warms by compression, thus taking the air farther from saturation, further reducing the likelihood for clouds in the eye, and contributing to the fair weather of the eye. </b> " http://www.hprcc.unl.edu/nebraska/develop.html

Need any other proof besides quotes from the top hurricane researchers in the biz? If you do...just ask and I can give you a few hundred more.

[Air Force Met]

Here are some more links to help describe it...

http://meted.ucar.edu/hurrican/strike/t ... utflow.jpg

http://marine.rutgers.edu/mrs/education ... 0winds.gif (notice the cyclonic circulation in the upper levels near the center of the storm.

The result of sinking air is warming air:
http://www.geog.ucsb.edu/~joel/g110_w05 ... _12_06.jpg

Again...
http://www.newmediastudio.org/DataDisco ... _fig10.jpg

[mike18xx]

(...)

[Ziplock]

This is one of the most interesting threads!

Great debate. I just love you guys.
Thanks,
Zip

[Pebbles]

Been following it closely here too...

[swimaster20]

Been following it closely here too...

ditto