Is the Gap Closing For Gordon to Escape?

[gatorcane]

Looks to be that the big subtropical ridge that is currently NE of TD7 is actually starting to build back westward now that Florence is clearing 35N. Also there is a decent ridge near Florida that looks to be building quickly east. These observations are based on Water Vapor analysis over the last 6 hours.

Thoughts on these new developments?

http://www.ssd.noaa.gov/goes/east/nwatl/loop-wv.html

[WxGuy1]

Maybe if TD7 was located down in the Caribbean... Models indicate continues northwesterly upper-level flow off the southeastern US coast through the next 72 hours. Storm-relative shear would be high for a path into the SE US, though there'd be no reason for it to head WNW or NW anyway.

The next decent upper-level trough is progged to come off the east coast this weekend. That should be enough to sweep Gordon back out to sea. HERE is the GFS 300mb forecast for Saturday evening.

[wjs3]

Hey, WxGuy1:

Interesting that you use the term "storm realtive shear". It's obviously a metric used in meso forecasting an awful lot, but I had never heard it in a tropical context until now, and always thought it would more accurately depict the shear a storm is "seeing" as it takes the storm's own motion into account. So I had been wondering...

Is there a storm-relative shear product for the tropics anywhere--is this variable actually calculated and analyzed?

Thanks!

[GeneratorPower]

gatorcane, I see in the WV imagery where the highs are pinching in closer together. Good observation.

[gatorcane]

gatorcane, I see in the WV imagery where the highs are pinching in closer together. Good observation.

I'm very surprised that there is not anymore debate than I am seeing on this. The ridges are clearly closing in on Florence's wake quite quickly today.

I still don't think this recurve track is very certain just yet.

[WxGuy1]

gatorcane, I see in the WV imagery where the highs are pinching in closer together. Good observation.

I'm very surprised that there is not anymore debate than I am seeing on this. The ridges are clearly closing in on Florence's wake quite quickly today.

I still don't think this recurve track is very certain just yet.

Yes, and you can see the upper-level trough over the northern and central plains poised to amplify with time as it sweeps eastward. This should provide enough southwesterly flow downstream of the trough axis to recurve Gordon out to sea. The dry air you sea to the west is associated with >30kt 300mb flow, which turns northerly by tomorrow to Gordon's west. I can't imagine shear will be too favorable for much intensification before he gets booted. The ECMWF doesn't seem as strong with the next upper-level trough forecast to move off the east coast, but there still seems to be some decent westerly mid- and upper-level flow north of Cuba (perhaps occassional northerly flow). Again, I think Gordon would have a much greater risk to the US if he was located several hundred miles southwest.

[GeneratorPower]

Well, and that is precisely what the NHC forecasters said last night. They said "highly uncertain" forecast track. That means highly uncertain!

One of the things that's nice about seeing your own WV loop is that you can spot trends and changes before they are published in the NHC updates.

There are two possibilities as to why there hasn't been more fuss over this. One, the pro-mets are seeing something in the overall pattern that still favors a northward motion, so therefore there is no need to change the thinking.

Two, they still haven't learned the Ernesto lesson.

[Stratosphere747]

Surely you just did not imply that the pros didn’t learn from the "Ernesto" lesson?

[donsutherland1]

Gatorcane,

The most recent GFS ensembles are reasonably similar to the animation I posted last night.



This animation, if it is correct, would strongly argue for recurvature.

[gatorcane]

gatorcane, I see in the WV imagery where the highs are pinching in closer together. Good observation.

I'm very surprised that there is not anymore debate than I am seeing on this. The ridges are clearly closing in on Florence's wake quite quickly today.

I still don't think this recurve track is very certain just yet.

Yes, and you can see the upper-level trough over the northern and central plains poised to amplify with time as it sweeps eastward. This should provide enough southwesterly flow downstream of the trough axis to recurve Gordon out to sea. The dry air you sea to the west is associated with >30kt 300mb flow, which turns northerly by tomorrow to Gordon's west. I can't imagine shear will be too favorable for much intensification before he gets booted. The ECMWF doesn't seem as strong with the next upper-level trough forecast to move off the east coast, but there still seems to be some decent westerly mid- and upper-level flow north of Cuba (perhaps occassional northerly flow). Again, I think Gordon would have a much greater risk to the US if he was located several hundred miles southwest.

so if that trough in the plains doesn't come to fruition then would the chances of recurvature be less?

[gatorcane]

Some more support for the gap closing....

Here is one for fun. THIS is not a forecast, and it is not official, for pete's sake.

I have not spent too much time on this system, but the current setup, although generally looks like it will end up recurving as forecast, has few bugs in it to me.

1. The ridge is building back to the NW of Gordie here quicker than the globals have it forecast. This would cause the system to track to the NW for say 12 hours ( maybe less) and then pick up a significant westward ( perhaps SW a jog or 2) motion for up at least 48 to 72 hours.

http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?wv_east_enhanced+12

[BensonTCwatcher]

Some more support for the gap closing....

Here is one for fun. THIS is not a forecast, and it is not official, for pete's sake.

I have not spent too much time on this system, but the current setup, although generally looks like it will end up recurving as forecast, has few bugs in it to me.

1. The ridge is building back to the NW of Gordie here quicker than the globals have it forecast. This would cause the system to track to the NW for say 12 hours ( maybe less) and then pick up a significant westward ( perhaps SW a jog or 2) motion for up at least 48 to 72 hours.

http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?wv_east_enhanced+12

Yes, it looks that way to me short term, long term this gets caught by the front off the EC. The models also disagree with me

[gatorcane]

alright folks, start posting away here. I think some members are actually thinking about what I thought when I wrote this thread......

I think that weakness for it to escape continues to get smaller based on WV analysis....now lets see what happens

latest WV image:

[gatorcane]

something else I am noticing tonight is that it may be getting nudged WNW now (albeit a more WNW than NW wobble) that is feeling the SW periphery of the subtropical ridge located to the NE....

hmmm...I think things may get interesting tomorrow.

[boca]

I noticed that on the IR and water vapor what you posted and it makes sense. I think this will move WNW or west for the next 2 days then veer north due to the trough in the plains moving east off the east coast.