ATL: GERT - Post-Tropical - Discussion

[SouthFLTropics]

What's with the random hopscotching?

It's no big deal...It's just playing Frogger!!! LOL

[OuterBanker]

Model wars are always interesting to watch. Euro pretty settled on developing the GOMEX. Not much with the Atlantic. GFS has pretty much decided to develop 99l. Let the war begin and may the best model win. I usually favor the Euro, but long range is still pretty much a toss up. Regardless, we have plenty of time to watch.

[Blown Away]

Model wars are always interesting to watch. Euro pretty settled on developing the GOMEX. Not much with the Atlantic. GFS has pretty much decided to develop 99l. Let the war begin and may the best model win. I usually favor the Euro, but long range is still pretty much a toss up. Regardless, we have plenty of time to watch.

Euro develops 99L, but keeps it very weak, and the model continues to plow and destroy 99L into PR/Hispaniola, so hard to tell if it would develop 99L if it were to miss the big islands N or S...

[OuterBanker]

Model wars are always interesting to watch. Euro pretty settled on developing the GOMEX. Not much with the Atlantic. GFS has pretty much decided to develop 99l. Let the war begin and may the best model win. I usually favor the Euro, but long range is still pretty much a toss up. Regardless, we have plenty of time to watch.

Euro develops 99L, but keeps it very weak, and the model continues to plow and destroy 99L into PR/Hispaniola, so hard to tell if it would develop 99L if it were to miss the big islands N or S...

I do think that the Euro has it too fast into the islands. I think that may be why it is depicting it as weak. But, first I would be concerned about the Gomex system.

[Frank2]

I'd say the GFS showing a pass between Florida and Bermuda is probably more realistic. The easterlies have been weak here in South Florida the past 10 days due to several strong troughs, and going into mid-August when the easterlies start to break down further, that usually means anything coming at us from the east is more likely to move more northward around the western side of the ridge.

Frank

[Steve]

I'd say the GFS showing a pass between Florida and Bermuda is probably more realistic. The easterlies have been weak here in South Florida the past 10 days due to several strong troughs, and going into mid-August when the easterlies start to break down further, that usually means anything coming at us from the east is more likely to move more northward around the western side of the ridge.

Frank

I'm not sure I'd agree that it's "more likely to move more northward around the western side of the ridge". 1) The troughs haven't been around most of the summer. This will probably end up having been a temporary pattern until Fall. 2) Of course you know this, but the GFS, though changed somewhat from previous seasons, usually does re-curve storms at the outset. And the farther west they get, the more it shifts its tracks. For those who don't know this, this isn't anything new. The GFS has had a known recurve bias (breaks down ridging too fast in and near the East Coast) for more than a decade. Similarly, the ECMWF has had a western and southern bias for over a decade. It's better than the GFS, though I doubt either one of them are right at this point beyond suggesting genesis and the likelihood that we have something to at least be concerned about in the western basin by next weekend. We still probably won't know in 10 days what's going to happen, but we will have a much better idea than now.

[Siker]

A little more support on the 12z EPS; ~5 members bring a TS beyond 60W.

[Frank2]

True, the troughs were absent until the past 2 weeks, but the timing is good as far as their eroding the ridge. The current 10-day loop doesn't show a very strong ridge, though the bias is in the run, that's true...

[stormlover2013]

Gfs always over does the trough

[otowntiger]

I'd say the GFS showing a pass between Florida and Bermuda is probably more realistic. The easterlies have been weak here in South Florida the past 10 days due to several strong troughs, and going into mid-August when the easterlies start to break down further, that usually means anything coming at us from the east is more likely to move more northward around the western side of the ridge.

Frank

I agree. This is the most likely outcome, simply because this is what a large majority of Cape Verde/Atlantic long trackers do - re-curve. Climo rules until actuality takes a rare but different course.

[HurricaneMaster_PR]

12Z UKMET run.

[KAlexPR]

12Z UKMET run.

How strong is it at that point?

[Siker]

12Z UKMET run.

How strong is it at that point?

Likely 975-980mb. Hard to get high res UKMET info.

[AJC3]

It goes without saying that we're going to want to pay very close attention to how the model solutions trend with the evolution of the 500MB low/trough between 60W and 70W in 7-10 days. As of right now, the GFS is stronger and slower to fill in this weakness between the ridge over the ATLC and FL/GOMEX. The ECM is quicker to do so, and is also weaker with 99L, so it sends what's left of the system westward at a lower latitude as opposed to rounding the western periphery of the ATLC ridge.

Assuming the system in near 20N60W in 7-8 days, here's what the Op-GFS and the op-ECM suggest the mid level ridge/trough pattern will look like ahead/to the north of it.

[Thetxhurricanemaster]

I am new here been lurking since 2008 during Ike, this tropical wave is very vigorous which should mean it slowly develops expect this to be weak and more west like the Euro, UK, Navgem show

[Sciencerocks]

It goes without saying that we're going to want to pay very close attention to how the model solutions trend with the evolution of the 500MB low/trough between 60W and 70W in 7-10 days. As of right now, the GFS is stronger and slower to fill in this weakness between the ridge over the ATLC and FL/GOMEX. The ECM is quicker to do so, and is also weaker with 99L, so it sends what's left of the system westward as a lower latitude as opposed to rounding the western periphery of the ATLC ridge.

So far this season with Bret, 4L and Don they have all had to deal with forward speed, SAL and shear. Wouldn't this trend favor the Ecmwf?

[floridasun78]

we could see two hurr in one week

[Siker]

It goes without saying that we're going to want to pay very close attention to how the model solutions trend with the evolution of the 500MB low/trough between 60W and 70W in 7-10 days. As of right now, the GFS is stronger and slower to fill in this weakness between the ridge over the ATLC and FL/GOMEX. The ECM is quicker to do so, and is also weaker with 99L, so it sends what's left of the system westward as a lower latitude as opposed to rounding the western periphery of the ATLC ridge.

So far this season with Bret, 4L and Don they have all had to deal with forward speed, SAL and shear. Wouldn't this trend favor the Ecmwf?

July's conditions are not August's. In fact, last week's conditions are often not this week's in the tropics. This will have to contend with some dry air and shear, but not as much as previous storms this season. How much dry air is an issue will also be directly tied into how much shear this encounters.

[AJC3]

It goes without saying that we're going to want to pay very close attention to how the model solutions trend with the evolution of the 500MB low/trough between 60W and 70W in 7-10 days. As of right now, the GFS is stronger and slower to fill in this weakness between the ridge over the ATLC and FL/GOMEX. The ECM is quicker to do so, and is also weaker with 99L, so it sends what's left of the system westward as a lower latitude as opposed to rounding the western periphery of the ATLC ridge.

So far this season with Bret, 4L and Don they have all had to deal with forward speed, SAL and shear. Wouldn't this trend favor the Ecmwf?

In terms of the system itself, I'd agree. I'd also favor the ECM and its ensembles in their forecasts of the 500MB height field. We'll see how everything trends with both the system, and the western extension of the Bermuda ridge at the mid levels. Still a week and half away and another dozen and a half plus worth of model runs to go.

[gatorcane]

Saved loop - has the look of a system that wants to get named:



Also coming into view on wide Atlantic shot. Looks like a big wave: