ATL : TROPICAL DEPRESSION ERIKA (06L)

[cycloneye]

This is a recent update from Dr Jeff Masters about 94L.

Invest 94L off the coast of Africa
A well-organized tropical wave (94L) lies a few hundred miles southwest of the Cape Verdes Islands, near the coast of Africa. This disturbance continues to look more organized on satellite imagery. Shear is low, about 10 knots, and waters are warm enough to support continued development. The dry Saharan Air Layer is relatively limited in extent and intensity, so dry air may have only a small inhibiting effect on the wave. Expect continued development of this wave as it moves westward over the next few days. NHC is giving this system a medium (30 - 50% chance) of developing into a tropical depression by Saturday. This system is moving rather slowly, 10 - 15 mph. The GFDL and HWRF models both predict 94L will be a Category 1 hurricane five days from now. These models also predict that 94L will take a significant northward jog 3 - 5 days from now, in response to a strong trough of low pressure passing to the north (this is the same trough of low pressure that will be recurving Danny out to sea).

[The Eye Wall]

12 z Euro not developing much, but does show the pattern change. Trough in the western U.S building ridge in the east

I'm not biting off on this scenerio just yet. I mean that is a complete reversal of what we've seen ALL summer long. Simply put, intuitively, it doesn't make sense. This is just talking off the top of my head with little to back it up, but IMO, I think that 94L will feel a tug northward (enough to miss the islands?) and then feel the building ridge, if indeed that's what happens. Perhaps pull and Andrew (hopefully not in strength). Keep in mind that I have not analyised the euro that much lately. From what I see per the gfs, looking out 144 hours, the ridge over the W. Conus builds and perhaps going zonal by 144 hrs (maybe this is the shift the euro is hinting at? I'm not sure). I understand the euro is showing 240 hours, but i'm looking for hints by other models.

I guess what I'm trying to say is that it would seem hard to break such a dominating ridge that has held stedfast all summer long by a digging trough. However, as we head later into the year, lower sun angle and shifting trade winds, it's bound to happen sometime.

72 Hours:



144 Hours:

['CaneFreak]

This is a recent update from Dr Jeff Masters about 94L.

Invest 94L off the coast of Africa
A well-organized tropical wave (94L) lies a few hundred miles southwest of the Cape Verdes Islands, near the coast of Africa. This disturbance continues to look more organized on satellite imagery. Shear is low, about 10 knots, and waters are warm enough to support continued development. The dry Saharan Air Layer is relatively limited in extent and intensity, so dry air may have only a small inhibiting effect on the wave. Expect continued development of this wave as it moves westward over the next few days. NHC is giving this system a medium (30 - 50% chance) of developing into a tropical depression by Saturday. This system is moving rather slowly, 10 - 15 mph. The GFDL and HWRF models both predict 94L will be a Category 1 hurricane five days from now. These models also predict that 94L will take a significant northward jog 3 - 5 days from now, in response to a strong trough of low pressure passing to the north (this is the same trough of low pressure that will be recurving Danny out to sea).

Yep...this is the year of the recurve...remind you of 1997 at all? HA

[Emmett_Brown]

12 z Euro not developing much, but does show the pattern change. Trough in the western U.S building ridge in the east

The problem with this map is that it has so few isobars on it, it is really hard to tell what the pattern actually is. By the looks of this, there is a trough in the W ATL, but I can't tell how far it digs. Does anyone have a more detailed EURO (with more streamlines?)

To me, this map implies that 94L is about to recurve into a weakness just after 60W.

[Derek Ortt]

the models have had the ridge building in all season... where is this mysterious ridge?

[Derek Ortt]

there was nothing to recurve in 1997

[drezee]

there was nothing to recurve in 1997

only real play in 1997 on the coast was.....drum roll....Danny...

['CaneFreak]

there was nothing to recurve in 1997

Oh really?

http://www.weather.unisys.com/hurricane ... index.html

Thats funny cause every storm that year but Danny recurved. Wow...

[The Eye Wall]

This is a recent update from Dr Jeff Masters about 94L.

Invest 94L off the coast of Africa
A well-organized tropical wave (94L) lies a few hundred miles southwest of the Cape Verdes Islands, near the coast of Africa. This disturbance continues to look more organized on satellite imagery. Shear is low, about 10 knots, and waters are warm enough to support continued development. The dry Saharan Air Layer is relatively limited in extent and intensity, so dry air may have only a small inhibiting effect on the wave. Expect continued development of this wave as it moves westward over the next few days. NHC is giving this system a medium (30 - 50% chance) of developing into a tropical depression by Saturday. This system is moving rather slowly, 10 - 15 mph. The GFDL and HWRF models both predict 94L will be a Category 1 hurricane five days from now. These models also predict that 94L will take a significant northward jog 3 - 5 days from now, in response to a strong trough of low pressure passing to the north (this is the same trough of low pressure that will be recurving Danny out to sea).

Yep...this is the year of the recurve...remind you of 1997 at all? HA

Even the names were the same in 1997. LOL.

[southerngale]

the models have had the ridge building in all season... where is this mysterious ridge?

Stuck in a few of the past seasons?

[KWT]

Thats true derek, the only reason I'd put a little more faith into it is becuase its September and typically at this time of the year the Bermuda high does tend to show just a little bit more bite before the subtropical jet really starts to rmap up again.

I still can't see this not recurving away though, the pattern still looks too troughy for a system like this to make it across unless it doesn't develop.

[KWT]

Those storms weren't really recurving though, to recurve means its had to have been going somewhere in the first place, those systems started out going ENE anyway. Only Erika (funnily enough!) really 'recurved' IMO.

Anyway this is pretty far south it has to be said, but I still can't see how this doesn't recurve, looks like a decent enough weakness will drag it north, the only shot it has is to stay weak, maybe not even forming.

This one won't be late enough to feel the effects of any pattern change IMO, its maybe the ones behind this one that needs closer watching...

[cycloneye]

This is the ample Central Atlantic image,but I think system can be captured by floater so NHC bring it on!.

[abajan]

Hmmm. According that this chart 50% of the models shown (2 of 4) are hinting at recurvature. I think that's pretty indicative of what may become of this one. The one interesting thing is it's current heading of wsw. That is going to work in favor of the argument that this thing becomes a player. I am now more interested to see what happens with this one.

From my observations, it's not that unusual for systems in the far eastern Atlantic to move wsw for a little while.

[ConvergenceZone]

Yep, I agree, looks like 2009 is the year of the recurves for sure..... I don't see any pattern changes.

and a month from now activity could be significantly winding down.

['CaneFreak]

Those storms weren't really recurving though, to recurve means its had to have been going somewhere in the first place, those systems started out going ENE anyway. Only Erika (funnily enough!) really 'recurved' IMO.

Anyway this is pretty far south it has to be said, but I still can't see how this doesn't recurve, looks like a decent enough weakness will drag it north, the only shot it has is to stay weak, maybe not even forming.

This one won't be late enough to feel the effects of any pattern change IMO, its maybe the ones behind this one that needs closer watching...

Ahhhh...Noooooo....Storms are supposed to travel east to west...not west to east....at least thats my definition of recurve

[otowntiger]

.[/quote]From my observations, it's not that unusual for systems in the far eastern Atlantic to move wsw for a little while.[/quote]

I didn't say that southwest motion was unusual, just interesting for the fact that it could keep it further south strengthening any argument of a long western tracker. Looking at the models now, this thing is sure to be a fish.

[KWT]

Yep, I agree, looks like 2009 is the year of the recurves for sure..... I don't see any pattern changes.

and a month from now activity could be significantly winding down.

Not really the place to discuss this but I actually suspect that there wil lbe a subtle pattern change, for a start the troughing down the east coast looks far weaker, esp on the ECM. The GFS isn't so drastic with this but it tends to be far too gung ho with upper trough features anyway, esp when the resolution goes down.

Anyway most of the convection is to the west so probably some sort of shear from the east on it at the moment, though its more likely that its still developing.

[ronjon]

the models have had the ridge building in all season... where is this mysterious ridge?

Actually the GFS has had the ridge building in all summer..the Euro has nailed the troughs pretty consistently throughout the summer. When it shows a deep trough out west, I pay attention.

[Rainband]

The last thing the US needs now is a disaster. I hope this season is a season of fish