Tropical Wave east of the Lesser Antilles (now Invest 92L)

[caneman]

We could have a Caribbean cruiser with this one. Why no model support?

[GCANE]

I mentioned a couple days ago that GFS was hinting at this developing.
It was kinda on again and off again for 850mb vort.
Convection is really going to town now.
Hitting 50W now where things usually start to heat up.

[GCANE]

Intensifying TPW

http://tropic.ssec.wisc.edu/real-time/m ... anim=html5

[GCANE]

700mb vort is well developed.
Very likely going to run thru mid Carib.
Could be one of those classic west-Carib RI TCs.
Need to dig into the models to check the setup.

[GCANE]

Models completely missing the boat on this one.
GFS and Euro showing practically no initialization of the LL vorts.
Very evident on CIMSS and just looking at the convection.

[GCANE]

CMC initializes in 30h and OTS

[Tampa Bay Hurricane]

CMC sends it out to sea because it develops it too early. It is a very large system and will take some time to consolidate and develop, hence getting further west and providing a seed for the caribbean and being a caribbean cruiser. This could be bad news for the caribbean, and then we will have to watch it very closely. GFS shows multiple cold fronts and troughs coming down about 7 days out, when this could be in the W Carib.

[GCANE]

CMC sends it out to sea because it develops it too early. It is a very large system and will take some time to consolidate and develop, hence getting further west and providing a seed for the caribbean and being a caribbean cruiser. This could be bad news for the caribbean, and then we will have to watch it very closely. GFS shows multiple cold fronts and troughs coming down about 7 days out, when this could be in the W Carib.

Latest GFS is also developing the vort and moving it NW to east of Bahamas and then OTS.
Very obviuous with the surface as an open wave and closed at 700mb, this will very likely run the Carib.
If this comes into the W Carib as a Cat 1 or 2, it could easily be one of those bad boys with a curve to the CONUS.

[GCANE]

If this runs the Carib, about 132 hrs out is when it should get near the Yucatan.
UL conditions clear as a bell, ripe for intensification.

[GCANE]

And then GOM clears out after that

[SouthDadeFish]

The 06Z GFS shows at least 20 kt of westerly shear throughout the Caribbean and GOMEX in 120+ hours. There is a huge upper-level trough over the Gulf. Those conditions aren't very favorable for TC development.

[GCANE]

The 06Z GFS shows at least 20 kt of westerly shear throughout the Caribbean and GOMEX in 120+ hours. There is a huge upper-level trough over the Gulf. Those conditions aren't very favorable for TC development.

Didn't Franklin have even higher shear NE of its LLC when it was in the W Carib?
Shear can create lift and fire off convection.
Its then a matter of the deep convection pushing the circulation down to the surface.

[SouthDadeFish]

The 06Z GFS shows at least 20 kt of westerly shear throughout the Caribbean and GOMEX in 120+ hours. There is a huge upper-level trough over the Gulf. Those conditions aren't very favorable for TC development.

Didn't Franklin have even higher shear NE of its LLC when it was in the W Carib?
Shear can create lift and fire off convection.
Its then a matter of the deep convection pushing the circulation down to the surface.

If there is positive vorticity in the upper-troposphere upshear of the TC, then yes, the shear can induce lift. This is related to quasigeostrophic omega arguments. However, I wouldn't say the presence of some shear is favorable for TC development after the genesis/weak TS stage. I'm not saying genesis is impossible, I just wouldn't call the forecast conditions favorable for TC development.

[Nimbus]

This time of year a developed storm will move slowly and might meander around the Caribbean like Mitch so longer range forecast is problematic.

[GCANE]

The 06Z GFS shows at least 20 kt of westerly shear throughout the Caribbean and GOMEX in 120+ hours. There is a huge upper-level trough over the Gulf. Those conditions aren't very favorable for TC development.

Didn't Franklin have even higher shear NE of its LLC when it was in the W Carib?
Shear can create lift and fire off convection.
Its then a matter of the deep convection pushing the circulation down to the surface.

If there is positive vorticity in the upper-troposphere upshear of the TC, then yes, the shear can induce lift. This is related to quasigeostrophic omega arguments. However, I wouldn't say the presence of some shear is favorable for TC development after the genesis/weak TS stage. I'm not saying genesis is impossible, I just wouldn't call the forecast conditions favorable for TC development.

Agreed. Once a TC forms, then shear becomes much more problematic. Thanks.

[Aric Dunn]

though most of the convection is on the east side of the wave axis there is at least two vorts one well to the south ( most likely to survive) and the to the north without convection. Is is maintaining convection quite well actually and shear on the southern portion is low.

the cmc shoots the northern vort north west because it also wants to develop that convection well north so the two systems interact.

otherwise the steering is to the west or wnw.. definately needs to be watched. very surprised not even a mention from the NHC..

[Gustywind]

though most of the convection is on the east side of the wave axis there is at least two vorts one well to the south ( most likely to survive) and the to the north without convection. Is is maintaining convection quite well actually and shear on the southern portion is low.

the cmc shoots the northern vort north west because it also wants to develop that convection well north so the two systems interact.

otherwise the steering is to the west or wnw.. definately needs to be watched. very surprised not even a mention from the NHC..

No special mention of the NHC good news... should stay a twave hopefully So great for us in the EC

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1228 PM EDT Thu Oct 12 2017


...TROPICAL WAVES...
A tropical wave extends from 08N52W to 18N49W moving W at 15-20
kt. The wave coincides with 700 mb troughing between 46W-55W and
a maximum in 850 mb relative vorticity along the wave axis near
13N. Scattered moderate and isolated strong convection is from
07N-18N between 43W-54W.

[Aric Dunn]

though most of the convection is on the east side of the wave axis there is at least two vorts one well to the south ( most likely to survive) and the to the north without convection. Is is maintaining convection quite well actually and shear on the southern portion is low.

the cmc shoots the northern vort north west because it also wants to develop that convection well north so the two systems interact.

otherwise the steering is to the west or wnw.. definately needs to be watched. very surprised not even a mention from the NHC..

No special mention of the NHC good news... should stay a twave hopefully So great for us in the EC

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1228 PM EDT Thu Oct 12 2017


...TROPICAL WAVES...
A tropical wave extends from 08N52W to 18N49W moving W at 15-20
kt. The wave coincides with 700 mb troughing between 46W-55W and
a maximum in 850 mb relative vorticity along the wave axis near
13N. Scattered moderate and isolated strong convection is from
07N-18N between 43W-54W.

Well I would not write it off just yet. there is cleraly a low level vort on the north end. the cmc, gfs, and 12z euro eventually develop it in some manner. as for it being any sort of threat to the islands that was never really an issue. shear is lowering especially on the south side. chances are not zero.. more around 30 to 40 percent in a few days.

[Tropics Guy]

Looks like a definite rotation around 12N 52W, at mid levels. Would think that the NHC would have given it a mention or % chance for development.

TG

[Sanibel]

Don't bite until the vort deepens IMO...