ATL : TROPICAL DEPRESSION ERIKA (06L)

[Derek Ortt]

same track as the CMC

Whats your thoughts on this?

isn't this the track I said all day yesterday if there is development? I always felt a track toward the US mainland was BS

[cycloneye]

As 94L decides what to do in terms of developing,in the meantime,it may bring some squally weather to some of the islands in the northern Leewards,unless it moves over 315 degrees and passes well away.

[deltadog03]

Well, the track has kinda been the same all along, but this is the first run that its actually depicting any real strength near the islands and then how it explodes and hooks north just east of the bahamas.

[tolakram]

Looking at the visible loop http://www.ssd.noaa.gov/goes/flt/t2/flash-vis.html

I see what I drew below. Maybe two areas of poorly defined circulation and the organization does not appear to be getting any better.

[vbhoutex]

Looking at the visible loop http://www.ssd.noaa.gov/goes/flt/t2/flash-vis.html

I see what I drew below. Maybe two areas of poorly defined circulation and the organization does not appear to be getting any better.

You are seeing what I saw and I looked at a couple of different sat loops on this. I'm not sure I can agree with a 50% chance of this becoming a TC anytime soon.

[cycloneye]

A Tropical Disturbance Statement was issued by the San Juan NWS office.They are doing this as many of the islands to the east get daily weather information from San Juan.I am sure they coordinated with NHC before this was released.Read it at our tent thread for the Eastern Caribbean at Weather Attic forum.

viewtopic.php?f=20&t=85676&st=0&sk=t&sd=a

[george_r_1961]

Last night we had some convection caused by this system interacting with a UL that was clearly shown on the shear map. There was some evidence of maybe an mlc.

This afternoon it looks horrible. Chances of development in the next 24-36 hours are near zero in my opinion.

[wxman57]

19Z surface plot & satellite. Not very impressive, currently.

94L is not looking too impressive, currently. Shear analysis indicates about 21-22 kts from 850mb-200mb. The disturbance is also moving into a region of accelerating easterly flow at 700mb . With two vorticity centers fighting for dominance, and with at least moderate shear, it may take a while to organize. There is evidence of a weak, elongated LLC . If one looks closely at a visible loop, it does look like the weak LLC is moving northwestward.

What can we deduce from the above? I think it’s looking less likely that 94L will become a hurricane prior to passing over or just north of the NE Caribbean on Thursday. So the threat to the NE Caribbean does appear to be decreasing. The GFS does indicate that the lower-level speed shear may decrease tomorrow. That could lead to much better organization by this time tomorrow. But the models that were forecasting it to be a hurricane all had it as a 35-40 kt TS by 12Z today. Clearly, that’s not the case.

In the long range, it’s not a certainty that it will recurve east of the U.S. 12Z GFS does indicate a possible south Florida threat, with a ridge building north of 94L in 5-6 days. Canadian turns it north a few hundred miles west of Bermuda. NOGAPS moves it toward the northern FL Peninsula. ECMWF moves it to just east of the Bahamas next Sunday then stalls it for a while before shooting it off to the NNE, passing just west of Bermuda on the 10th of September. Clearly, it's too early to make a confident call that this may not be a threat to the East U.S. Coast once it passes the NE Caribbean.

As for development chances, NHC still says “High”, meaning >50%. I suppose I’d agree that chances of development are greater than 50%. But maybe not by much.

[dtaylortgo]

Im no expert but I wanted to ask you guys where you think this thing will be in 6 days? The only reason I ask is Im leaving for a cruise on Sunday from Florida. is this thing going to be there yet or will we leave in time?

Thanks

[gatorcane]

The ECMWF shows a big trough in the Western CONUS and a big ridge in the Eastern CONUS but then has some kind of "backdoor" trough that digs down from Novia Scotia down into the Western Atlantic that sucks it up.

Usually with a large trough in the west you will have a large ridge in the east so not sure I buy this ECMWF bomb out recurve just before the Bahamas.

[hurricanefloyd5]

Looking at the visible loop http://www.ssd.noaa.gov/goes/flt/t2/flash-vis.html

I see what I drew below. Maybe two areas of poorly defined circulation and the organization does not appear to be getting any better.

You are seeing what I saw and I looked at a couple of different sat loops on this. I'm not sure I can agree with a 50% chance of this becoming a TC anytime soon.

http://www.ssd.noaa.gov/goes/flt/t2/loop-rb.html The center is under all that conviction see it all!!!!!!

[wxman57]

http://www.ssd.noaa.gov/goes/flt/t2/loop-rb.html The center is under all that convection see it all!!!!!!

There's no way that you can that you can deduce that the center is under the convection using that IR loop. Stick to a high-res visible loop to find and track low-level clouds.

[Stormcenter]

Why not buy it? It's been like this (E.C. troughs)almost all season.

The ECMWF shows a big trough in the Western CONUS and a big ridge in the Eastern CONUS but then has some kind of "backdoor" trough that digs down from Novia Scotia down into the Western Atlantic that sucks it up.

Usually with a large trough in the west you will have a large ridge in the east so not sure I buy this ECMWF bomb out recurve just before the Bahamas.

[storms NC]

http://www.ssd.noaa.gov/goes/east/carb/loop-vis.html

You can see the top being blown off in this loop. So No I don't think they will call any thing till it is able to hold on to it's convection and have a well define LLC.

[southerngale]

I thought there was supposed to be a building ridge, according to the Euro this morning. Now it recurves it. So this run is more plausible?

It's hard to keep up with the ever-changing model scenarios. Some of the others trended west.

[BigA]

Some observations from the cheap seats...I am not an expert.

The reason that the NHC is concerned about 94L's possibility of development, rather than assuming shear will destroy it is because the shear is hauling westward rapidly. For instance, take a look at the Wisconsin Shear tendency map. http://cimss.ssec.wisc.edu/tropic/real- ... g8sht.html

If you compare the 18Z shear map to the 15Z map, it is clear that the ULL that is causing the shear is moving westward at a good clip. The models (GFS, NOPGAPS, CMC, NAM) show this continuing. Essentially, this is a race that 94L has to lose in order to develop. If it moves westward too rapidly, the shear eats it. If the shear moves more quickly, 94L has a decent chance.

Furthermore, in determining where exactly the MLC of 94L is, the Wisconsin 850mb vorticity can help. Between the 15Z and 18Z updates, the 850mb vorticity has gotten stronger, and is more or less co-located with the big ball of convection. If a surface low were to become established, it would likely be here. http://cimss.ssec.wisc.edu/tropic/real- ... 8vor4.html

[hurricanefloyd5]

when is recon flying into 94L

[x-y-no]

I thought there was supposed to be a building ridge, according to the Euro this morning. Now it recurves it. So this run is more plausible?

It's hard to keep up with the ever-changing model scenarios. Some of the others trended west.

It's still building a ridge, but doesn't keep it as long. So the system stalls then heads NE when the ridge decays. I don't know that either scenario is more plausible at this point.

EDIT: If I had to guess, I'd go with the recurve since that's been the pattern so far this year.

[Sanibel]

Come back in 24 hours.

[x-y-no]

when is recon flying into 94L

Tomorrow afternoon.