Professional mets--outflow channels

[wjs3]

Help me....

Many of us on the board know that outflow helps a tropical cyclone develop...and read a lot about outflow in TPC discussions.

Here's my question--what's the difference between outflow and an outflow channel?

I believe the 5 PM TPC discussion on Frances described an outflow channel, and Mwatkins, in one of his posts, described an outflow channel pumping the ridge north of Frances. (Mwatkins, can you help? Love your posts!)

What's the differecen between outflow and an outflow channel? I get that outflow can pump a ridge, but how does and outflow channel change/enhance that? What should we look for on sattelite (WV? IR?) to identify an outflow channel vsoutflow, and what does it mean?

Thanks!

WJS

[ericinmia]

I am no met. however i believe this may help with your question.

As the hurricane sucks in the wet/moist warm air from the sea surface, it expels it dry and colder through the eye and out through the whispy bands you see surrounding a healthy hurricane. Sometimes this expelation of air is fed straight into a high to the north of the storm, thus intensifying the high and helping the high remain on track just north of the hurricane.

hope that is of some good...
-Eric

[wjs3]

Appreciate yourt reply.

I understand what you describe as basic Tropical cyclone structure--inflow at the lower levels, outflow at the higher levels. I guess my question is specifically why today we started hearing about outflow channels--rather than just garden variety outlflow--on Frances, and what difference there is, if any, between outflow as you describe it and an otflow channel.

Thanks!

[ericinmia]

As the storm gets closer to the high and begins to ride its lower boundary, because of this close relationship the high begins to feed off the storm. When storms are casually crossing the atlantic after coming off the coast of africa, they generally are not directly associated with, or connected to a high.

When the storm is father away from the high, its outflow generally is dispersed evenly in all directions, however as it gets very close to a building high, the outflow becomes more channeled toward the high.

Sorry its late, and i'm having trouble using the brain. The good explenation and vocabulary in there is done for the night.
-Eric

[Stormsfury]

In Isabel last year, before the transition to Isabel becoming an annular hurricane, it had a very strong outflow channel on the southern/SW'ern side (the outflow channel was greater than 50 kts) which allowed the hurricane to vent itself, very efficiently ...

SF

[wjs3]

Ericinmia

Got it now. Sorry I didn't understand earlier. I think I was the one too tired to make any sense!

To make sure I understand...an outflow channel is a connection to a nearby surface high--at phases in a TC's life, it can have outlow evenly in all quadrants--but asit it becomes associated with a building suface ridge, it actually can hav particularly good outflow right to that ridge helping it build...and that's an outflow channel.

Right?

Thanks for helping me with my curiosity!