TS Ernesto #8 Sat pics, models, analysis thread

[Droop12]

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?

He may be right, except the shears coming from the SW and moving NE.

[Windtalker1]

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)

I do not think this is weakening my any means.

[ronjon]

The feathery appearance is a sign of an anti-cyclone forming over the top of the storm. Its the evacuation of the warm air below being drawn into the upper levels of the atmosphere. Its typically associated with stengthening systems. It is not shear, quite the opposite.

[Stormcenter]

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)

I do not think this is weakening my any means.

I tell you what if you look at the loop below it almost looks like it's hitting a brick wall (shear). Does not look as impressive as it did earlier.

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

[whereverwx]

Thanks for the explanation, Wthrman13...

[Grease Monkey]

Looks like it's beginning to hit some nice moisture. Looks like Ernesto is doing fine right now, not perfect, but doing well:

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

[Extremeweatherguy]

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)

I do not think this is weakening my any means.

I tell you what if you look at the loop below it almost looks like it's hitting a brick wall (shear). Does not look as impressive as it did earlier.

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

according to the met above, this is actually not a bad thing. It does not mean more shear.

[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.

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

Yes, the LLC, as far as I can tell, is just under the edge of the outflow from the convection on the NW side. So, it's holding it's own and may even be intensifying slightly at the time being. The shear ahead of it is still pretty robust, but has been decreasing steadily all day:

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

I'd say this has a pretty good chance of holding together.

[A1A]

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

I think you are in disagreement with . . .

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.

[Grease Monkey]

actually that might be true because it kind of makes it easier for the LLC to catch up with the convection?

[Mac]

Anybody else noticing those extremely cold cloud tops popping very close to (if not right over) the LLC??? Ut oh...

[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)

I do not think this is weakening my any means.

Well, I don't think so either. But on those frames when the feathery edges showed up, the darker purple on the WV contracted a bit. I was really using the T-storm example as just an analogy.

But just in the last 2 frames or so, you can see on the NW edge, another pocket of deeper convection is starting near the LLC. If this continues, it will be getting better organized overnight.

Anyway, I'm tired and not very coherent any more. time for bed...

[Stormcenter]

[quote="Grease Monkey"]Looks like it's beginning to hit some nice moisture. Looks like Ernesto is doing fine right now, not perfect, but doing well:

http://www.ssd.noaa.gov/goes/flt/t2/loop-wv.html[/quote

I respectfully disagree. He looked better earlier. Now he looks more elongated.

[Wthrman13]

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

I think you are in disagreement with . . .

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.

Well, the convection is pulsing, and this is leading to periodic "advancements" of the outflow on the NW side, while the LLC underneath plows steadily WNW. It is true though that the outflow can become more "ragged-looking" as the convection decreases. However, this sort of radial feather pattern, in my experience, has always been a sure sign of intense active convection in TC's.

[Droop12]

Anybody else noticing those extremely cold cloud tops popping very close to (if not right over) the LLC??? Ut oh...

Yep, Ernesto's being very persistent I must say.

[Mac]

I think the storm is trying to come together...bringing the heart of the convection over the LLC. Watch that loop. Look at the very cold cloud tops popping on the NW quad by the LLC.

[KFDM Meteorologist]

Here's the new GFS from 00Z..It's aiming at New Orleans. Notice the weakness between the 2 highs..

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_144l.gif

[Extremeweatherguy]

It looks like it hit some really strong shearing forces to me...that's what the feathery appearence appears to me as because if you watch the convection continues to build west until suddenly it stops and the feathery lines appear. This, perhaps, may mean that the storm has finally begun to feel the effects?

k e v i n . c h o
naples, fl

read witherman's post above.

[Mac]

Here's the new GFS from 00Z..It's aiming at New Orleans. Notice the weakness between the 2 highs..

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_144l.gif

I was afraid of that...could be a setup for some mega-outflow... oh boy.

[Wthrman13]

It looks like it hit some really strong shearing forces to me...that's what the feathery appearence appears to me as because if you watch the convection continues to build west until suddenly it stops and the feathery lines appear. This, perhaps, may mean that the storm has finally begun to feel the effects?

k e v i n . c h o
naples, fl

The UL winds are out of the WSW just to the NW of the storm. As the storm continues further WNW, the cirrus outflow (the feathery pattern) will likely get caught up in that flow and start moving ENE. Do you follow me? That hasn't happened yet, however, at least with the active convection near and the SE of the circulation center.