ATL: GERT - Post-Tropical - Discussion

[otowntiger]

Interestingly enough, although 99L is said to be moving WNW, the 8:05 PM TWD stated that the associated low was centered near 15.5N45.5W but the latest TWD places the low near 15N47W. Assuming the earlier TWD's forecaster opted to be more precise than the latter's, it appears that the low has moved directly westward. However, if it's not a matter of precision and the coordinates in the latter TWD are actually 15.0N47.0W, then the low has in fact moved in a slightly south of west direction. Could it just be a wobble?

. When you are talking about a large disorganized mass of clouds and showers it's really hard to focus on its precise movement/coordinates. And only well organized hurricanes with well defined centers can actually "wobble", lol!

[Kingarabian]

00z Euro 96-216hrs.

[jlauderdal]

starting to warm up on this system once it moves into the western Atlantic. May very well get a TS or a cane out of this

would prefer the euro be right over sofla

[cycloneye]

 https://twitter.com/BigJoeBastardi/status/894883489949949952

[cycloneye]

8 AM TWO up to 30% in 5 days.

A trough of low pressure located about 800 miles east of the Lesser
Antilles continues to produce an area of disorganized showers and
thunderstorms. Development of this system is not expected during the
next few days due to unfavorable environmental conditions. However,
some development of this system is possible this weekend while the
system moves generally west-northwestward at about 15 mph over the
western Atlantic.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

[Emmett_Brown]

99L has a long wave axis, and the track will be highly dependent upon where the low spins up along the wave. Euro shows the low forming on the northern part of the wave, then 99L takes a significantly NW motion by day 3. If the low forms more to the south, I would think the track could be affected, so details of the recurve not etched in stone yet. The ball of convection that 99L is sporting this morning is due to sheer from a ULL to the NW... Visible sat images show a broad low level turning much further SW, near 15N, 51W, moving almost due west.

[Patrick99]

The low level circulation looks like it's moving due west. Looks pretty barren to me right now, but I guess we may eventually have to watch for a closer-in development.

[cycloneye]

12z Bext Track:

AL, 99, 2017080812, , BEST, 0, 154N, 502W, 25, 1011, DB

[TheStormExpert]

FWIW the 06z GFS has trended towards the Euro with an EC recurve.

[weathaguyry]

Not sure how the Euro has done with ridging, but if the ridge builds in just a little more this will be into the OBX/Long Island/Cape Cod

[RL3AO]

0z EPS. Most show no intensification during the first 5 days or so.

[GlennOBX]

0z EPS. Most show no intensification during the first 5 days or so.

http://i.imgur.com/sFL1bF1.png

Can someone explain what the levels of shading/colors represent?

Thanks

[Emmett_Brown]

Not sure how the Euro has done with ridging, but if the ridge builds in just a little more this will be into the OBX/Long Island/Cape Cod

Well, last year the Euro had Matthew safely missing the E Coast; then, just a few days before landfall, it trended W with a building ridge. That was in October, so it can happen, especially in August.

[RL3AO]

0z EPS. Most show no intensification during the first 5 days or so.

http://i.imgur.com/sFL1bF1.png

Can someone explain what the levels of shading/colors represent?

Thanks

The spatial distribution of the European Ensembles. The brighter the colors, the more members agree that the low will be near that point.

[WAcyclone]

0z EPS. Most show no intensification during the first 5 days or so.

http://i.imgur.com/sFL1bF1.png

Unfortunately, that website seems to update very infrequently for whatever reason. Today's 00z EPS graphic is still not shown yet...

[RL3AO]

0z EPS. Most show no intensification during the first 5 days or so.

http://i.imgur.com/sFL1bF1.png

Unfortunately, hat website seems to update very infrequently for whatever reason. Today's 00z EPS graphic is still not shown yet...

I didn't even realize it was the wrong days. It's hit or miss, especially during the invest stage.

[gatorcane]

This abrupt NNW turn between hours 48 and 72 on the 00Z ECMWF is interesting. Is this really the vorticity moving NNW or does a new vorticity develop along the northern axis? That is like a 500 mile north jump there that would have track implications downstream:

[JPmia]

Maybe its where the actual COC consolidates? I am suspicious when the first direction in the models points to a recurve north.

[Bocadude85]

FWIW the 06z GFS has trended towards the Euro with an EC recurve.

There is nothing even trackable on the 6z GFS, it does not develop 99L.

[AJC3]

FWIW the 06z GFS has trended towards the Euro with an EC recurve.

There is nothing even trackable on the 6z GFS, it does not develop 99L.

While it's much weaker than the other global models, the GFS 850MB vortex is indeed trackable, and it does recurve just east of the Bahamas.