ATL : TROPICAL DEPRESSION ERIKA (06L)

[Emmett_Brown]

A few observations:

1. This disturbance is still very healthy, and could still develop IF the upper level winds improve.
2. Meanwhile, because it's still a wave, it is continuing to head more westerly with the low level flow, bringing it closer to land masses of the Leeward Islands and Bahamas. (Note that it is just a wave, so getting close to land doesn't mean severe conditions at this time)
3. The forward speed of 94L has slowed to 10 mph, which would mean that 94L should stay east of the worst shear today.
4. Shear has been slow to subside, but 0Z GFS still insists in building a nice anticyclone by this evening over 94L, see below:

[Derek Ortt]

outflow boundaries

I do not see the need for recon today. We KNOW this is a wave. Would be good for HRD to fly to study genesis, but they decided not to deploy to Barbados for this system

development, if any, should be slow and limited. Should be code yellow or maybe orange. Not red

[wxman57]

outflow boundaries

I do not see the need for recon today. We KNOW this is a wave. Would be good for HRD to fly to study genesis, but they decided not to deploy to Barbados for this system

development, if any, should be slow and limited. Should be code yellow or maybe orange. Not red

NHC code red only means a >50% chance of it becoming a TD within 48hours. What do you think its chances are of becoming a TD by 12Z Thursday? 30%? 40%?

[Derek Ortt]

outflow boundaries

I do not see the need for recon today. We KNOW this is a wave. Would be good for HRD to fly to study genesis, but they decided not to deploy to Barbados for this system

development, if any, should be slow and limited. Should be code yellow or maybe orange. Not red

NHC code red only means a >50% chance of it becoming a TD within 48hours. What do you think its chances are of becoming a TD by 12Z Thursday? 30%? 40%?

given the shear (from the upper trough nobody seems to be noticing in the Carib) and the poor organization, probably in the 30-40% range

[wxman57]

I still think it will most likely turn north to the east of the Bahamas, but we can't yet rule out a U.S. East Coast hit.

What are you and Derek seeing that makes you think recurve?

The 500mb flow pattern indicates a fair weakness north of 94L off the East U.S. Coast. If it develops, then there isn't much to keep it on a westerly path. If it DOESN'T develop, it may track more westward, but it would just be a heavy rain threat.

Here's a combo 500mb chart with heights every 10 meters. The pink lines are the GFS forecast for 144hrs. The yellow lines are the European model forecast valid for the same time.

[tolakram]

Shear is a tad better today.



But you can clearly see the conveyor belt on the visible loop: http://rammb.cira.colostate.edu/ramsdis ... _floater_2

Crazy system.

However on the closeup loop: http://rammb.cira.colostate.edu/ramsdis ... is_floater

It appears there is at least one (not well) defined circulation near the convection.

http://rammb.cira.colostate.edu/ramsdis ... is_floater

[AtlanticWind]

outflow boundaries

I do not see the need for recon today. We KNOW this is a wave. Would be good for HRD to fly to study genesis, but they decided not to deploy to Barbados for this system

development, if any, should be slow and limited. Should be code yellow or maybe orange. Not red

I just dont see that this could be code yellow meaning less tha 30 percent chance of this being a depression in the next 2 days . this has at least a 40 if not 50 percent chance of forming by thursday morning. Plus recon may get some good info on the enviroment near 94L

[Emmett_Brown]

Just because it hasn't developed yet, doesn't make this a non threat. There is plenty of warm water in the Bahamas and FL Straits. If this continues west as as strong wave, it could still develop and cause problems, as we have seen in recent years. Certainly the threat to the Lesser Antilles islands seems to be diminishing today (since it is currently weak).

[Sanibel]

Another Fay lesson. Great IR and form and little underneath.


Danny never got it together under this track.

[Dean4Storms]

Well the models are not totally worthless, they do show the synoptic patterns down the road and most of them are beginning to show a sizable east coast ridge down the road. If we have Erika by then and she is out east of Florida she could very well get trapped and be a threat to the SE CONUS!

[AtlanticWind]

Vis. loop shows a circulation near 16.5 56.5 recon should be able to find a T.D. today

[Stormcenter]

Hmmmmm.....I don't think it will get that far west.

Just because it hasn't developed yet, doesn't make this a non threat. There is plenty of warm water in the Bahamas and FL Straits. If this continues west as as strong wave, it could still develop and cause problems, as we have seen in recent years. Certainly the threat to the Lesser Antilles islands seems to be diminishing today (since it is currently weak).

[Dean4Storms]

I agree, you cannot just go by a Sat. presentation when trying to determine if a Wave has a closed LLC!!!

[bob rulz]

Vis. loop shows a circulation near 16.5 56.5 recon should be able to find a T.D. today

I don't see anything definitive on the visible loop.

[Evil Jeremy]

Vis. loop shows a circulation near 16.5 56.5 recon should be able to find a T.D. today

I don't see anything definitive on the visible loop.

I see what he is seeing, but I don't think it is an LLC.

[Gustywind]

Kevin Roth, & Mark Avery, Lead Meteorologists, The Weather Channel
Sep. 1, 2009 9:52 am ET
http://www.weather.com/newscenter/tropical/

ATLANTIC

A broad area of low pressure about 300 miles east of the Lesser Antilles has seen another flare up of shower and thunderstorm activity this morning. It is unclear at this point if the low pressure circulation is occurring at the surface, or if it is a few hundred feet aloft.

The Hurricane Hunters will be investigating this system early this afternoon to determine how well organized it is. Depending upon what they find this low could be classified as a tropical depression or tropical storm later today.

The low is moving to the west-northwest near 15 miles per hour. Interests in the Lesser Antilles and Puerto Rico should monitor the progress of this system.

Elsewhere it is quiet across the Atlantic Basin.

[gatorcane]

Well the models are not totally worthless, they do show the synoptic patterns down the road and most of them are beginning to show a sizable east coast ridge down the road. If we have Erika by then and she is out east of Florida she could very well get trapped and be a threat to the SE CONUS!

I dont agree. If it can develop into a hurricane models will quickly start to show a recurve prior to the Bahamas and East of the CONUS.

[Evil Jeremy]

How will the through coming off the coast affect the ULL to the NW?

[Bocadude85]

Well the models are not totally worthless, they do show the synoptic patterns down the road and most of them are beginning to show a sizable east coast ridge down the road. If we have Erika by then and she is out east of Florida she could very well get trapped and be a threat to the SE CONUS!

I dont agree. If it can develop into a hurricane models will quickly start to show a recurve prior to the Bahamas and East of the CONUS.

Just because models are showing a system that has not even developed yet recurve does not mean things can't change. Not saying this will not recurve out to sea just saying thats it a little premature to say recurve when in fact we currently do not even have a system to recurve.
Models do and will change.. I can recall quite a few systems that models showed heading out to sea but ended up hitting the CONUS. Hurricane Ike would be a good recent example.

[Sanibel]

20-30KT shear isn't going to help push this one over the top.

2009 - Year of deceptive presentation.