TS Ernesto #8 Sat pics, models, analysis thread

[LAStorm01]

Sky, I miss them too...I keep waiting for John to post again, and hopefully, if things develop, David will post too..This new crew????? Dan Milham downplayed development @ 10, so maybe there is something to it... Sorry for the chat.

[jasons2k]

On that water vapor image, you can also see that feathered appearance happening simulateously on the southeast side of the storm. It appears only in the last few frames. What in the world would cause that on both sides of the storm like that??? I've only seen that before with shear. But on both sides of the storm at the same time???

I see it too clearly on the water vapor as well. I think it's a sign of the convection decreasing in size a bit, rather than expanding. Maybe a pro met could explain better.

Warning: high bandwidth:

http://www.atmos.washington.edu/~ovens/ ... nhanced+12

[Mac]

Mac - my guess is improving outflow...

I don't think so, my friend. I've never seen outflow that was explosive like that. I think it's shear coming from the northwest. If you look at that loop really carefully, you can see that the feathering first appears on the nw quad of the storm and then carries across to the southeast side. It's just hard to see the direction because the southeast side of the storm is not as well defined. But if you watch it over and over slowly you can see it. Man, that must be some wall of shear it hit to make the storm react that way. It doesn't appear to be affecting the storm yet, though.

[Noles2006]

Yeah, what threw me off was how it's around the entire storm.... to be honest, I have only looked at one pic this evening and haven't had a chance to check out any loops...

[A1A]

Here's a side by side pic showing how Ernesto has now developed a "feathery" western side? Does someone know what is causing that?

[Extremeweatherguy]

It does look like convection/clouds are expanding on the west side. May be it is better outflow?

[Mac]

Look at the image again. It's not just on the western side. It's also on the southeast side. I think this is being caused by higher shear...coming from the northwest side of the storm. Either that, or Ernesto just hit a windshield out there in the Caribbean.

[Extremeweatherguy]

Look at the image again. It's not just on the western side. It's also on the southeast side. I think this is being caused by higher shear...coming from the northwest side of the storm. Either that, or Ernesto just hit a windshield out there in the Caribbean.

I don't know why NW shear would allow the clouds to expand on the W side of the storm though. that wouldn't make sense...would it?

[Wthrman13]

The "feathery" appearance is the cirrus outflow from the storm. Notice how it is oriented radially outward from the center of the convection area? That indicates a large amount of upper-level divergence. There is still shear, but the convection is so intense that some of the outflow is fighting against it on the west side. The same thing happens in continental thunderstorms in regions of high shear; you can get what are called "backsheared" anvils that flow against the environmental winds at upper levels. It's one indication of an intense updraft.

[Mac]

Look at the image again. It's not just on the western side. It's also on the southeast side. I think this is being caused by higher shear...coming from the northwest side of the storm. Either that, or Ernesto just hit a windshield out there in the Caribbean.

I don't know why NW shear would allow the clouds to expand on the W side of the storm though. that wouldn't make sense...would it?

It seems like I've seen this before and asked the same question. I can't recall the exact explanation, but think about if you drop a pebble in a lake. Does the water all move away from you or does it not also splash back at you???

[skysummit]

Look at the image again. It's not just on the western side. It's also on the southeast side. I think this is being caused by higher shear...coming from the northwest side of the storm. Either that, or Ernesto just hit a windshield out there in the Caribbean.

I don't know why NW shear would allow the clouds to expand on the W side of the storm though. that wouldn't make sense...would it?

That's what I was about to post. How would northwest winds allow clouds to expand into the shear? I hope someone answers that question with the two pics. I've seen it before, but I'm wondering it myself.

[cpdaman]

PROMETS a little help here what is the feathery stuff oops sorry wtherman13 thanks for the info

[miamicanes177]

So much for that SAL:
18 hours ago
NOW

[rockyman]

Actually, when I checked the loop a while back, the western edge of the convection was contracting slightly back toward the east

[jasons2k]

I think it was sharper earlier b/c the convection was clearly expanding. Now it's ragged as it decreases in size.

Similiar to a thunderstorm. When a TCU cloud is building into a storm, it has nice, sharp edges to it (the "popcorn" look). When the storm is weakening, the top looks feathery & ragged.

edited: typos (I'm tired)

[skysummit]

Here we go....

The "feathery" appearance is the cirrus outflow from the storm. Notice how it is oriented radially outward from the center of the convection area? That indicates a large amount of upper-level divergence. There is still shear, but the convection is so intense that some of the outflow is fighting against it on the west side. The same thing happens in continental thunderstorms in regions of high shear; you can get what are called "backsheared" anvils that flow against the environmental winds at upper levels. It's one indication of an intense updraft.

[Mac]

The "feathery" appearance is the cirrus outflow from the storm. Notice how it is oriented radially outward from the center of the convection area? That indicates a large amount of upper-level divergence. There is still shear, but the convection is so intense that some of the outflow is fighting against it on the west side. The same thing happens in continental thunderstorms in regions of high shear; you can get what are called "backsheared" anvils that flow against the environmental winds at upper levels. It's one indication of an intense updraft.

Ahhhh. Thanks. That makes sense.

[bevgo]

Fla us now officially un the clear--No Cone touches Fla so there is a ZERO chance of Fla Getting this

No one is out of danger yet.

[Extremeweatherguy]

The "feathery" appearance is the cirrus outflow from the storm. Notice how it is oriented radially outward from the center of the convection area? That indicates a large amount of upper-level divergence. There is still shear, but the convection is so intense that some of the outflow is fighting against it on the west side. The same thing happens in continental thunderstorms in regions of high shear; you can get what are called "backsheared" anvils that flow against the environmental winds at upper levels. It's one indication of an intense updraft.

thanks for that answer. So this may actually be a sign it is holding it's own?

[theworld]

The "feathery" appearance is the cirrus outflow from the storm. Notice how it is oriented radially outward from the center of the convection area? That indicates a large amount of upper-level divergence. There is still shear, but the convection is so intense that some of the outflow is fighting against it on the west side. The same thing happens in continental thunderstorms in regions of high shear; you can get what are called "backsheared" anvils that flow against the environmental winds at upper levels. It's one indication of an intense updraft.

Yes, it actually began on the WSW side.
http://www.atmos.washington.edu/~ovens/ ... nhanced+12