ATL: HARVEY - Post-Tropical - Discussion

[northjaxpro]

I am thinking the area west of 91L will take over as the main vort area. 91L will get merged into it. This will initialize the system a bit more south.

This is going to be quite a week ahead tracking this entity, plus viewing the eclipse next Monday in SC.

[GCANE]

So far the GFS 700mb Lagrangian OW forecast has been spot on.
Currently a large area SW of CV islands with good convergence and divergence.
Brewing under a large anticyclone free of SAL.
Two vort areas.
Something likely to pop out of this around Wednesday.

[GCANE]

The only hurdle I see for 91L at this point is possible mid-layer dry air & 355K PV interaction just before the islands.

If it holds on and can make it into the Carib or Bahamas, all the ingredients look good for a spin up.

Given the ridging forecast at this point a CONUS landfall is not out of the question.

[cycloneye]

@BigJoeBastardi
Think eastern system will be Harvey by weekend . Path likely north of Franklins, but west of Gerts day 6-10

 https://twitter.com/BigJoeBastardi/status/897046180407988225

[Steve H.]

Okay folks, we know this is 10+ days out for the US, and the models will shift thousands of miles over the next few days The fact that some models dropped this feature is horse hockey right now. IMO, we will have a TC to deal with during the next 10 days or so. Where it will go (general area) will be more refined later this week. No sense in getting all riled up at this point, save your energy for when we may need it (preparation and so forth). We're approaching the heart of the season soon, so stay vigilant.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

[cycloneye]

8 AM TWO up to 20%-60%

Shower and thunderstorm activity associated with a broad trough of
low pressure southwest of the Cabo Verde Islands has increased
since last night. Environmental conditions are expected to be
generally conducive for development of this disturbance for the next
several days while it moves westward at about 15 mph over the
tropical Atlantic.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...60 percent.

[SFLcane]

Hmmm getting vibes this morning of Franklin this night not even affect the US entirely with strong high pressure over it. Wait and see folks with models killing all entirely.

[jlauderdal]

Hmmm models this morning getting vibes this morning of Franklin this night not even affect the US entirely with strong high pressure over it. Wait and see folks with models killing all entirely.

nhc trend is for development so the killing off idea is bunk for now, stout ridge looks like a good bet but very difficult to get something all the way across and stay south of texas, lets see if that ridge hangs tough and can actually drive it wsw down the road, we have seen it before katrina, etc

[ouragans]

No more mention of any merger of the 2 systems... Do they consider it already happened?

And there are clearly 2 different systems.

[cycloneye]

@JimCantore
8am NHC update has initiation point west by about 10 degrees longitude. FWIW, this was best taken into account already by the ECMWF.

 https://twitter.com/JimCantore/status/897068364966883328

[RL3AO]

I still like the Euro with an intensifying TD/TS just east of the islands. A system this broad will take some time to develop. Now, if it decides to go across Hispaniola and Cuba, then it probably won't survive (even with the 0z Euro forecast). If it misses Hispaniola, then watch out.

[tolakram]

Build You Own GOES 16 visible

https://weather.msfc.nasa.gov/cgi-bin/get-abi?satellite=GOESEastfullDiskband02&lat=14&lon=-40&width=1400&height=900&zoom=4&type=Animation&numframes=15&quality=90

[cycloneye]

12z Best Track has been adjusted 10 degrees ahead and now there is any doubt 91L will continue to be the one and no 92L is comming.

AL, 91, 2017081412, , BEST, 0, 125N, 338W, 25, 1011, DB

06Z Best Track position.13.3N-24.5W



12z Best Track position 12.5N-33.8W

[cycloneye]

NRL adjusts to the 10 degree westward change.

[KWT]

Hmmm getting vibes this morning of Franklin this night not even affect the US entirely with strong high pressure over it. Wait and see folks with models killing all entirely.

Typically these systems end up going west of the original forecast, I actually think the ECM is decent in terms of track, but IF there is an error, its going to trend to the south/west IMO.

I'm fairly confident it will form though, it has that look of a slowly curling broad low area. (A little WPAC in nature actually in terms of looks)

[Emmett_Brown]

This wave does have a classic look to it. The baby pictures of big 'canes often look like this... big sprawling envelope

[emeraldislenc]

The next days will be interesting for certain.

[emeraldislenc]

Does the initialization of the system further west have any bearing on the track?

[tropicwatch]

Whether it goes into the Caribbean or north into the Atlantic. It looks like the models take it close to the Leeward Islands, Puerto Rico and Hispaniola at this point.

[wxman57]

I believe that the NHC had initialized 91L too far east. It's clear that the system the models are developing is closer to 13N/35W as of 12Z today. I can see rotation near 12.5N / 35.5W (below). This is the area to watch. Euro ensembles take it into the NE Caribbean on Saturday as a TS. Depending upon how much of the Greater Antilles it impacts, it could be a Gulf or SE U.S. hurricane threat next Tue/Wed.