Trough of low pressure in Western Caribbean (Is Invest 95L)

[Hurricaneman]

At the very least, the GFS is showing what may be a severe impact to Cuba and the Bahamas in the coming week.

True, needs to be watched as far west as the Panhandle but I think the brunt will be in the Bahamas, Cuba and possibly Florida depending on 94L

[SouthFLTropics]

00z GEFS Ensembles... Hot off the press

[AutoPenalti]

00z GEFS Ensembles... Hot off the press

https://i.imgur.com/cuSwyIz.gif

Very widespread solutions after 7 days...

[AJC3]

0z GFS a tad S and a couple mb stronger than 18z through hour 174... Looks to potentially be another big run... also 94L much stronger and more defined than 18z

More importantly, 94L much further west. May open the door for this to escape East of Florida.

Sent from my iPhone using Tapatalk

Solid points being made about 94L here.

The strength/location of 94L beyond days 5-7 will have a huge impact on the strength of the western Atlantic ridge, which in turn, will be the main factor in how close to Florida the Caribbean disturbance (assuming it forms as advertised) will get to Florida. The farther west it goes, the "bigger hole it can chew" in the flank of the ridge, and the more likely a NE-ward escape becomes. However, one point I'd like to make: From my experience, global model guidance rarely underdoes the extent of westward retrogression of these subtropical latitude cutoffs that try to become STCs/TCs. While not always the case, I've observed that more often that not, these features don't retrograde as far west as model solutions advertise. It takes a strong ridge to push these types of lows significantly westward at a decent forward speed. Instead, what often happens is that they become quasi-stationary, or only drift westward at a much slower clip. Again, no guarantee that this will happen in this case, it's strictly an anecdotal observation.

But the strength/position of both the western Atlantic ridge and 94L need to be looked at closely over the next week plus...

[tomatkins]

0z GFS a tad S and a couple mb stronger than 18z through hour 174... Looks to potentially be another big run... also 94L much stronger and more defined than 18z

More importantly, 94L much further west. May open the door for this to escape East of Florida.

Sent from my iPhone using Tapatalk

Solid points being made about 94L here.

The strength/location of 94L beyond days 5-7 will have a huge impact on the strength of the western Atlantic ridge, which in turn, will be the main factor in how close to Florida the Caribbean disturbance (assuming it forms as advertised) will get to Florida. The farther west it goes, the "bigger hole it can chew" in the flank of the ridge, and the more likely a NE-ward escape becomes. However, one point I'd like to make: From my experience, global model guidance rarely underdoes the extent of westward retrogression of these subtropical latitude cutoffs that try to become STCs/TCs. While not always the case, I've observed that more often that not, these features don't retrograde as far west as model solutions advertise. It takes a strong ridge to push these types of lows significantly westward at a decent forward speed. Instead, what often happens is that they become quasi-stationary, or only drift westward at a much slower clip. Again, no guarantee that this will happen in this case, it's strictly an anecdotal observation.

But the strength/position of both the western Atlantic ridge and 94L need to be looked at closely over the next week plus...

One thing Ive noticed looking at the 0Z GFS, GFSP and Euro is that the stronger 94L is early, the further east it is. Could be a confirmation of this principle - harder to push a stronger storm around.

[kevin]

It's very difficult to see in these cluttered ensembles, but I think I saw 9 or 10 Florida landfalls this time so a 43% - 48% chance based on 00z GFS.

[ElectricStorm]

6z GFS running... Has 94L in a similar spot to the 0z run. Let's see if it still pulls this system NE.

[ElectricStorm]

Hour 162: Caribbean system much weaker, 94L much stronger

[otowntiger]

I see the GFS back to being sane again. Keeps this system well to the east. Big surprise, not. Just like I figured.

[Loveweather12]

Things will change considering we are a week out and we have no low.

I see the GFS back to being sane again. Keeps this system well to the east. Big surprise, not. Just like I figured.

[cycloneye]

8 AM.

A broad area of low pressure is expected to form in a few days
over the southwestern Caribbean Sea. Some gradual development of
this system will be possible through the middle of next week while
it moves slowly northward or north-northwestward over the western
Caribbean Sea.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

[gatorcane]

8 AM.

A broad area of low pressure is expected to form in a few days
over the southwestern Caribbean Sea. Some gradual development of
this system will be possible through the middle of next week while
it moves slowly northward or north-northwestward over the western
Caribbean Sea.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

Shading more north:

[ElectricStorm]

I see the GFS back to being sane again. Keeps this system well to the east. Big surprise, not. Just like I figured.

I think it's a little too early for that call... One run most definitely does not mean it's going to happen. One thing I noticed about this GFS run though is that it makes 94L a hurricane pretty quickly after it forms, if it starts out subtropical as expected, I would think it would take a little longer to become a full fledged hurricane than this run shows. I am in no way -removed- for a major, but to me the 0z run looks more plausible at this point in time, at least through 240 hours. Obviously it's a complicated setup that ultimately depends on 94L's development. If 94L does indeed get stronger quicker, then the 6z solution may be more likely. Still way out though and a low hasn't even formed yet so all the models will likely change many more times lol

[aspen]

The weaker and east shift on the models appears to be due to the remnant vorticity of 93L. It gets drawn into the Caribbean by the precursor low and creates a second lobe that prevents Zeta from getting further west.

The precursor to Zeta emerges into the Caribbean between 18z Monday and 12z Tuesday. Over the next two days, the gyre/area of rotation enlarges, with another area of spin over Central America, causing Zeta’s precursor vorticity to take a while to concentrate and be swung around the western lobe.

I don’t know if the models are correctly predicting the actual shape of the gyre, or if they’re getting very confused about any little piece of vorticity in the region.

[boca]

The weaker and east shift on the models appears to be due to the remnant vorticity of 93L. It gets drawn into the Caribbean by the precursor low and creates a second lobe that prevents Zeta from getting further west.

The precursor to Zeta emerges into the Caribbean between 18z Monday and 12z Tuesday. Over the next two days, the gyre/area of rotation enlarges, with another area of spin over Central America, causing Zeta’s precursor vorticity to take a while to concentrate and be swung around the western lobe.

I don’t know if the models are correctly predicting the actual shape of the gyre, or if they’re getting very confused about any little piece of vorticity in the region.

Where do you think the low will form by Jamaica or further west and will the low by ejected NE by 94L?

[aspen]

The weaker and east shift on the models appears to be due to the remnant vorticity of 93L. It gets drawn into the Caribbean by the precursor low and creates a second lobe that prevents Zeta from getting further west.

The precursor to Zeta emerges into the Caribbean between 18z Monday and 12z Tuesday. Over the next two days, the gyre/area of rotation enlarges, with another area of spin over Central America, causing Zeta’s precursor vorticity to take a while to concentrate and be swung around the western lobe.

I don’t know if the models are correctly predicting the actual shape of the gyre, or if they’re getting very confused about any little piece of vorticity in the region.

Where do you think the low will form by Jamaica or further west and will the low by ejected NE by 94L?

It looks like the central precursor low comes off of the coast of Colombia, around Santa Marta. That won’t happen until mid-late Monday. The low seems to try to move NW on the models, but it becomes blocked by the randomly forming western lobe, and the forming Zeta is forced to rotate into Jamaica and Cuba earlier within the suddenly huge area of spin.

I don’t particularly buy the model solution of this normal-sized area of spin suddenly ballooning to nearly half the width of the Caribbean. If Zeta’s precursor concentrates earlier, those solutions might not happen.

[Blown Away]

The ENE movement out of the Caribbean is pretty aggressive for October, but the timing will be near the end of October, so the 06z GFS track is in line with November track climatology. October/November can bring some crazy tracks.

[Kazmit]

Just checked the latest GFS and wow, storms really like Bermuda the year that I'm not there.

[Gums]

Salute!

Do not forget Charley's track once it got rolling. Then Irene of 1999 in October that year. We are getting our typical fronts every 5 or 6 days now, and of course, they have a high pressure system behind them to the north that usually moves east or north east. Don't pack up your "grab and go" bag yet.

Although I have hearing noise problems (jet noise damage, not loud rock and roll, heh heh), I still can't hear the fat lady warming up, can you?

Gums sends...

[aspen]

I've highlighted the two possible tracks of Zeta: either the eastward shift due to a gigantic gyre, or one that's further west and more in-line with the GFS/GFS-Para runs that have a smaller gyre. The latter will be a far more worrying track because Zeta would have anywhere from 4-6 days between its starting off point and Cuba landfall to develop and intensify. Even the east track would have nearly as much time, although with much more land interaction with Jamaica. Quicker development than the 06z runs show will, obviously, mean more time to strengthen, but if conditions on Monday-Wednesday prohibit this, then the west track will yield the highest intensity.