ATL: EX-Tropical Depression FIVE - Discussion

[KWT]

lebron23, just out of interest how strong do you think this one will get?

Always interested in hearing peoples different views!

MGC, yeah this maybe a little slow to get of the ground, it needs to try and focus some low level convergence into the center rather then having it focused further out, thats more of a subtropical trait then pure tropical...probably the lingering after effects of its extra-tropical birth.

[lebron23]

lebron23, just out of interest how strong do you think this one will get?

Always interested in hearing peoples different views!

MGC, yeah this maybe a little slow to get of the ground, it needs to try and focus some low level convergence into the center rather then having it focused further out, thats more of a subtropical trait then pure tropical...probably the lingering after effects of its extra-tropical birth.

Right now i'm thinking about 50-60 but would not be shocked to see a weak cat 1

[Dean4Storms]

Shear right now looks like just 5kts according to this and I don't see where the shear is coming from in the models or what NHC is saying. A Anti-Cyclone is clearly setting up over this system which could cause some rapid development, only once nearing the SE CONUS Ridge centered over GA and the ULL to the west once in the northern Gulf could I see any shear, but by then this could be quite deep!!

http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html

[KWT]

Another thing to note: the ULL that is north of the system is also helping to pull in dry air from the SE U.S. The ULL looks like it will continue to head west and end up in the WGOM while TD 5 scoots WNW as a ridge builds into the NE of TD 5. So TD 5 will be in a squeeze play between the ULL and ridge headed WNW/NW and accelerating in the process. This looks very similar to what we saw with Bonnie which just could not get her act together despite boiling SSTs......

I think the NHC sees an increase in the shear aloft for reasons you partly suggest.

I don't really think its going to speed up so much to cause any real issue for this sort of system, its clearly got a large broad low and its not going to have the ULL match it blow for blow like Bonnie did...neither will it have the low level moving at 30kts like it did with Colin.

Dean I agree with that, I'm going to have a look at Low level convergence to see whether that explains the ring of convection it has right now, could just be an aftereffect of its birth I spose.

[CYCLONE MIKE]

Shear right now looks like just 5kts according to this and I don't see where the shear is coming from in the models or what NHC is saying. A Anti-Cyclone is clearly setting up over this system which could cause some rapid development, only once nearing the SE CONUS Ridge centered over GA and the ULL to the west once in the northern Gulf could I see any shear, but by then this could be quite deep!!

http://cimss.ssec.wisc.edu/tropic/real- ... g8shr.html

Thank You Dean. That is exactly what I was saying earlier. I can't for the life of me figure out where the NHC is getting that shear will inhibit stronger development. Especially since the last couple of days they have said conditions will gradually improve across the gulf for more development.

[cpdaman]

seems like given the 48 hours or so to landfall....the biggest hurdle for the sytem to overcome in order to strengthen to a minimal cane is it's broad size.

but are we sure this thing is a good size....i mean is it conclusive

[KWT]

Thank You Dean. That is exactly what I was saying earlier. I can't for the life of me figure out where the NHC is getting that shear will inhibit stronger development. Especially since the last couple of days they have said conditions will gradually improve across the gulf for more development.

The models do increase the shear over it and thats probably why they are nearly all weak this system, however there can quite often be some disconnection between what happens and what the models prog to happen, esp with small upper level features.

[Stormcenter]

You are correct but I'd give TD5 a much better chance of being a stronger (50-60mph) system at landfall then Bonnie ever had. IMO

Another thing to note: the ULL that is north of the system is also helping to pull in dry air from the SE U.S. The ULL looks like it will continue to head west and end up in the WGOM while TD 5 scoots WNW as a ridge builds into the NE of TD 5. So TD 5 will be in a squeeze play between the ULL and ridge headed WNW/NW and accelerating in the process. This looks very similar to what we saw with Bonnie which just could not get her act together despite boiling SSTs......

[gatorcane]

You are correct but I'd give TD5 a much better chance of being a stronger (50-60mph) system at landfall then Bonnie ever had. IMO

Another thing to note: the ULL that is north of the system is also helping to pull in dry air from the SE U.S. The ULL looks like it will continue to head west and end up in the WGOM while TD 5 scoots WNW as a ridge builds into the NE of TD 5. So TD 5 will be in a squeeze play between the ULL and ridge headed WNW/NW and accelerating in the process. This looks very similar to what we saw with Bonnie which just could not get her act together despite boiling SSTs......

Agreed, that's about the intensity I would give it....

[CYCLONE MIKE]

Thank You Dean. That is exactly what I was saying earlier. I can't for the life of me figure out where the NHC is getting that shear will inhibit stronger development. Especially since the last couple of days they have said conditions will gradually improve across the gulf for more development.

The models do increase the shear over it and thats probably why they are nearly all weak this system, however there can quite often be some disconnection between what happens and what the models prog to happen, esp with small upper level features.

KWT what models and what do they see that causes the increase in shear? Don't think it will be the ULL as it is steadily pushing off to the west and looks to be getting weaker as the day goes as well. Then of course that will be replaced by high pressure building in in place of it. Like I said earlier, even up to the last TWO the NHC has said conditions in the gulf will gradually become more favorable.

[Hurricane]

Texas was farther in the cone than I thought it would be.

[ozonepete]

You are correct but I'd give TD5 a much better chance of being a stronger (50-60mph) system at landfall then Bonnie ever had. IMO

Another thing to note: the ULL that is north of the system is also helping to pull in dry air from the SE U.S. The ULL looks like it will continue to head west and end up in the WGOM while TD 5 scoots WNW as a ridge builds into the NE of TD 5. So TD 5 will be in a squeeze play between the ULL and ridge headed WNW/NW and accelerating in the process. This looks very similar to what we saw with Bonnie which just could not get her act together despite boiling SSTs......

Agreed, that's about the intensity I would give it....

I posted the CIMSS mid and low level dry air analysis a few pages back. There is NO dry air over the southeast U.S. or anywhere else near this system right now. And there isn't any forecast to be.

[KWT]

From what I've seen pretty much all of the models increase the easterly shear to some extent, hence why the NHC forecast is rather conservative.

Gatorcane, thats personally something around what I'd go for as well, something close to Edouard...because it is quite large and I'm not totally happy with the convection distrubtion, granted that can change in a matter of hours!

[TeamPlayersBlue]

I think now that the storm is getting more organized, within the next few hours, we will have a very good idea on how strong it will become before landfall. As someone said earlier, it is very big. A bit like Alex at this stage as far as its large size for a TD

[LSU2001]

I surely don't want to second guess the pros at NHC but I agree with a lot of ya'll in saying that the calls for non-conducive environment may be premature. I for one hope that the NHC has it dead on and all of the second guessing is alarmist with this thing due to go right over my head. I can tell you that today at school as I talked with my colleagues that most had no clue that something was brewing. If this thing gets going and gets any stronger than a minimal TS we will be caught off guard. As of now we don't really have time to evacuate assets out of the flood prone areas outside of the levees and with all of the oil spill workers in the area, with many not knowing about the flooding issues in this area we are primed for a bad time if this thing gets going.
Sorry for the rant,
tim

[HURAKAN]

Development chances yesterday at 8 pm were 40% for the next 48 hours. TD #5 overcame the odds put on by the NHC.

[LSU2001]

Good point Hurakan,
This storm has defied the odds thus far and as the day went on it continued to get better organized despite the non conducive environment. Can it continue to beat the stats????

[dixiebreeze]

I think a lot of folks will wake up Wednesday to a big surprise.

[MiamiHurricanes10]

Here's the thing (which is why I think that 05L will become a minimal hurricane). The ULL currently north of 05L (as noted on water vapor) is advecting westward. This ULL will be leaving the picture very soon along with the dry air. Now, the deep-layer ridge will begin to build back in tomorrow evening, thus it will begin to shear 05L starting tomorrow. However, this shear will be easterly. You may be thinking, shear is shear, this thing won't be able to develop. Well, easterly shear isn't as tarnishing to a westward motion cyclone as one may think. Why you may ask? Well, shear coming from the east towards the west essentially flows in tandem with the cyclone. As opposed to shear coming from the west moving towards the east going against the cyclones flow thus having a much more tarnishing affect. Yes, this is what happened with Bonnie. However, with Bonnie the easterly shear was much stronger and faster than the actual cyclone. This is not the case with 05L because the easterly shear is moving just as fast as 05L is, plus it won't be too strong. Catching on?

[Nimbus]

There should be a window for some development even if the shear forecast is spot on. You can see the rotating high dropping down in the water vapor loop, but there is a possibility it could bridge around any anticyclone that develops over TD5.