Disturbance in the western Caribbean (Is invest 98L)

[KWT]

Yeah thats a good point AJC3, that seems like more of a November type evolution though so remains to be seen whether that even comes off yet.

[Ivanhater]

In the interest of full disclosure for the Florida peeps, throughout the medium/extended range, both the ECM and GFS continue to show mid to upper level westerlies over the GOMEX and FL - 250 MB westerlies are progged to be at least 40-50kt over the keys/straits, and they increase to at least 60-80kt between 25N and 30N.

You can't just look at the surface progs and declare some sort of threat without looking at the mid and upper levels to see that threat is minimized by horrid u/l conditions. For a serious Florida threat to materialize, you would need a change in the mid/upper pattern that would cause the 500MB-250MB to weaken and back more to southerly - i.e. significant upstream amplification or blocking. For instance, the ECM solution of a mid level cutoff low digging into the deep south/NE GOMEX from days 5-9 would need to occur about 10 degrees or so farther west.

That was my point earlier. The Caribbean looks to be favorable for development but conditions do not look favorable for a U.S threat. With the shear that is forecast, anything attempting to go the way of the Gulf or Florida is going to be ripped to shreds. Pattern could change though, but as persistent as it has been, I would not bet on it.

[alienstorm]

Looking at Hi-Resolution visible loop development seems to be occurring at roughly 14N and 79W.

[Vortex]

18Z GFS rolls in 45 min....

[gatorcane]

In the interest of full disclosure for the Florida peeps, throughout the medium/extended range, both the ECM and GFS continue to show mid to upper level westerlies over the GOMEX and FL - 250 MB westerlies are progged to be at least 40-50kt over the keys/straits, and they increase to at least 60-80kt between 25N and 30N.

You can't just look at the surface progs and declare some sort of threat without looking at the mid and upper levels to see that threat is minimized by horrid u/l conditions. For a serious Florida threat to materialize, you would need a change in the mid/upper pattern that would cause the 500MB-250MB to weaken and back more to southerly - i.e. significant upstream amplification or blocking. For instance, the ECM solution of a mid level cutoff low digging into the deep south/NE GOMEX from days 5-9 would need to occur about 10 degrees or so farther west.

Note the cut-off low in the ECMWF digging into the Southern US. That is why it is developing this system and the GFS is not currently. The upper-level low is causing the upper-level winds to veer to the SSW across the Southern GOM and Florida. Now should the cut-off low dive down into the GOM a bit more west, it could allow this system to get closer to Florida than what this run is showing. Given this is all in the long-range anyway, no need to speculate on track details at this point. Let's just see if it develops in the Western Caribbean first.

http://www.ecmwf.int/products/forecasts ... 0100712!!/

[HURAKAN]

vorticity keeps increasing

[Vortex]

In the interest of full disclosure for the Florida peeps, throughout the medium/extended range, both the ECM and GFS continue to show mid to upper level westerlies over the GOMEX and FL - 250 MB westerlies are progged to be at least 40-50kt over the keys/straits, and they increase to at least 60-80kt between 25N and 30N.

You can't just look at the surface progs and declare some sort of threat without looking at the mid and upper levels to see that threat is minimized by horrid u/l conditions. For a serious Florida threat to materialize, you would need a change in the mid/upper pattern that would cause the 500MB-250MB to weaken and back more to southerly - i.e. significant upstream amplification or blocking. For instance, the ECM solution of a mid level cutoff low digging into the deep south/NE GOMEX from days 5-9 would need to occur about 10 degrees or so farther west.

You summed it up perfectly gator...

Note the cut-off low in the ECMWF digging into the Southern US. That is why it is developing this system and the GFS is not currently. The upper-level low is causing the upper-level winds to veer to the SSW across the Southern GOM and Florida. Now should the cut-off low dive down into the GOM a bit more west, it could allow this system to get closer to Florida than what this run is showing. Given this is all in the long-range anyway, no need to speculate on track details at this point. Let's just see if it develops in the Western Caribbean first.

http://www.ecmwf.int/products/forecasts ... 0100712!!/

[Ivanhater]

The Euro ensembles do not agree with the Operational run. The Euro ensembles are in agreement with the GFS and GFS ensembles.

All models, both operational and ensembles show very unfavorable conditions all across the Gulf and Florida. I don't see this particular storm being an issue for the U.S. Maybe the next one, but the next one will be getting quite late in the season. Still keep an eye open though. The end of October and November have been known to throw out some potent storms all across the Gulf, although rare.

[Vortex]

Ivan, can you post those? I won't have accesss till later tonight. Thx!

[Ivanhater]

Euro ensemble mean 192 hours....No cut-off low

[Vortex]

very different picture than the operational for sure...

[SouthDadeFish]

How would that change the upper-air pattern in terms of shear?

[Vortex]

18Z GFS at H18...low establishing itself by tomorrow morning over the SW carribean



http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_018l.gif

[Vortex]

Not so sure it doesn't get stuck down there and miss the connection...

[Vortex]

H42 spinning over the SW carribean


http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_042l.gif

[gatorcane]

18Z NAM:

[AJC3]

Note the cut-off low in the ECMWF digging into the Southern US. That is why it is developing this system and the GFS is not currently. The upper-level low is causing the upper-level winds to veer to the SSW across the Southern GOM and Florida. Now should the cut-off low dive down into the GOM a bit more west, it could allow this system to get closer to Florida than what this run is showing. Given this is all in the long-range anyway, no need to speculate on track details at this point. Let's just see if it develops in the Western Caribbean first.

http://www.ecmwf.int/products/forecasts ... 0100712!!/

I've looked at much higher resolution data than the coarse graphics that are available online (and If I could post them, I would). The upper level winds only back to SW (and not SSW) as far north as 24-25N. To the north, across Florida, it's screaming W to WSW flow of greater than 60kt (closer to 50kt over the Keys). While there is a little more backing of the flow toward the SW at 500MB, it's not nearly meridional enough to imply a threat to Florida, and the magnitude of the winds in the 500MB to 250MB layer shows a very hostile shear environment. The GFS would need to trend toward the ECM cutoff solution, and then both would need to trend toward a farther west solution for Florida to even sniff a serious TC threat at this point.

My post was geared toward any potential threat to Florida from the western Caribbean at this point, since I often see a tendency toward discussing factors that favor tropical development or threat to a particular area, and a corresponding lack of discussion of the negative factors.

[Vortex]

H144 going nowhere anytime soon...models are anything but consistent...typical for this time of year....

[Vortex]

H162 remains over southern carribean...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_162l.gif

[Vortex]

GFS continues back and forth with getting picked up or being left behind.