Atlantic Tropical Wave/Disturbance Thread 2008

[kold weather]

Well depsite only being March this thread is being created to discuss any system that stands a chance or sticks out as being a possible tropical system in the future. Once the system has been tagged as an invest the system is then to be disucssed in the Invest thread which will be created when one comes along.

Anyway to kick us off there is a low pressure system with a fairly tight pressure gradient in the central Atlantic presently. We are at the time of year where the upper atmosphere is pretty cold still and this is probably helping to increase the lapse rates enough to mean that despite the cooler SST's the relative instablity is high enough for a warm cored system to develop. Its certainly not there yet and its still a bit of a long shot but there are just hints that the system is becoming more symmetric and with starting to gain a weak shallow warm core. Obs shows winds in the center of 35kts and so it is an interesting first system to watch of 2008 for the Atlantic. I'm not going to lose sleep over this system mind you but its interesting just in case something does occur I wouldn't toally rule out an invest on this system.

[Cookie]

I look forward to reading as always

[kold weather]

Interesting tropical wave presently in the tropical Atlantic region. Whilst I don't think it will develop what is interesting about this feature is it simply being as far west as it is. At this time of year normally waves that reach 15W will decay rapidly however this one has had decent convective coverage for the last 36hrs and given the lack of upper level easterlies the system has sort of stalled over the same sort of water for that period and yet its not decayed which is very interesting indeed.

I suspect the fact that waters in the region are between 1-2C are a big reason why convection is still present. Once it moves out of this area eventually it should decay. Also should be noted its a little south of where the dry dusty air is present that would weaken waves during the early summer. Still looks like the first decent tropical wave of the spring and the first hints of what is to come in the next 7 months!

Edited April 8, 2008 by kold weather

[Cookie]

thanks for update mate wouldn't have know about that other wise

[kold weather]

Well the Atlantic is finally starting to heat up along the inter-tropical convergence zone (ITCZ) in the eastern Atlantic. it seems a little early to get this sort of activity occuring given the ITCZ is still quite far south (sometimes we don't even see this sort of activity in mid-July!) and I storngly suspect that the very above normal waters in the east Atlantic is playing a big role in the deep convection present. Already a couple of fairly decent tropical waves make it out to 30-40W before finally losing energy due to cooler waters.

[Cookie]

thats good news

[kold weather]

Decent waves still coming off Africa for the time of year being helped by the higher then average precip over the 'winter' months over Africa and higher then normal sea surface temperatures in the eastern Atlantic is helping to fuel these waves. Indeed there is one wave in the eastern Atlantic that appears to have quite a healthy looking circulation though convection isn't all that deep and well organised, for the time of year its very impressive.

However right now I am just going to turn my attention to the possiblity of a Sw Caribbean/Eastern Pacific system that could form in 5-7 days time. Right now there is a lot of convection is the region though its clearly very disorganised in nature, this convection is probably being enhanced by the Colombian low that is normally present at this time of year in that region.

Models are keen on developing some sort of low pressure center however there is some disagreement between the models. The GFS has been keen for quite some time to develop a low pressure system in the SW Caribbean and then take it northwards towards the gulf. Meanwhile various other models such as the ECM, UKMO and the CMC all develop something in the eastern Pacific inside the next 144hrs and indeed the ECM develops it into a fairly strong looking system, probably a hurricane by 192hrs...

So we've got something to watch now, whilst this system could form in the eastern Pacific the SW Caribbean will have to keep watching in case something forms, however unless the other models side with the GFS I feel the EPAC idea is the better one right now.

Edited May 23, 2008 by kold weather

[Cookie]

thanks for the update mate :o

[Iceberg]

Morning All,

Good Spot Kold, it's probably the only area near the states that's really capable of creating a Cane at the moment with a small pocket of 30C in the pacific and a small pocket in the Atlantic of +28C.

GFS interestingly forms a TS at 168 in the Atlantic with the first named storm of the season(or preseason!).

ECM, METO et al all keen to keep it in the pacific feeding of the +30C pool and forming quite a storm for this early in the season.

Certainly one to watch.

Looking across the Atlantic SST's are still fairly low and the ITCZ quite far south, (although reasonably active). We still need the start of our summer and the moving of the Azores High to the NE, to allow the ITCZ to drift northwards enough, probably still 2 to 3 weeks away IMO.

Still the activivity around central america and the tropical waves around should keep things interesting pre season.

Cheers

Matt

[kold weather]

Good post Matt, the point about the ITCZ is true its still fairly far south but at the moment that has helped to give really low SAL levels in the Atlantic, its really low indeed and if that keeps up along with the other factors expect several powerful Cape Verde hurricanes to form this season.

Anyway a slight change in the models I've seen so far in favor of the GFS which still develops a decent looking system in the SW Caribbean then takes it NW towards the Yucatan, though on this run it then bedns back NNE somewhat.

However the change is that the ECM now does not develop a system in the EPAC and instead forms a closed low in the SW Caribbean as well. The ECM shows a weak system granted but it does have a closed low in the same place as the GFS and that the first time I've seen both models in some sot of agreement which has got to argue in favor now of the GFS solution being right though the other models still going for an EPAC system.

[Iceberg]

Yep agree I have a feeling that a very varied season is coming up.

The differences between the GOM and Atlantic are very apparent atm, Not really any chance of a start of season GOM storm, but the Atlantic will get going when temps come up. The one concern I have is that the extensive cloud cover will depress SST's.

[kold weather]

I don't think thats cloud cover thats just the moisture levels in the atmosphere, there is very little cloud cover present bar the waves and some weak cloud cover a little further north:

http://www.ssd.noaa.gov/eumet/eatl/vis-l.jpg

So the fact there is such huge levels of moisture in the atmosphere is also yet another good sign for an active Cape Verde season.

[Iceberg]

I think there are tentative signs that the ITCZ might drift north in around 5 days time or so. A window of oppotunity might present it's for a verde storm.

[Cookie]

Nothing much expected till Friday at the earliest

[kold weather]

Yeah its fairly queit out there, still a wave with neat looking circulation is present around 10N 45W at the moment but is badly lacking in deep convection and given conditions ahead of it are probably on the wrong side of marginal nothing should form from it. If it can make it into the Caribbean, esp further west then chances start to rise but for now thats a very very long way away.

[tinybill]

Yeah its fairly queit out there, still a wave with neat looking circulation is present around 10N 45W at the moment but is badly lacking in deep convection and given conditions ahead of it are probably on the wrong side of marginal nothing should form from it. If it can make it into the Caribbean, esp further west then chances start to rise but for now thats a very very long way away.

just been reading another site they sending up a plane to look at that tropic wave might be worth keeping an eye on it

[Cookie]

I wouldn't have thought they would bother with tropical waves?

[Somerset Squall]

I wouldn't have thought they would bother with tropical waves?

Depends if it is associated with a low pressure system or if it's showing signs of convective organisation. But in this case, I severely doubt the NHC would bother.

[Cookie]

thanks mate for answering

[summer blizzard]

A TROPICAL WAVE IS ALONG 27W/28W S OF 15N MOVING W NEAR 10-15

KT. SATELLITE IMAGERY CONFIRMS THE POSITION OF THE WAVE AXIS WITH

A DISTINCT LOW/MID LEVEL CYCLONIC CIRCULATION AHEAD OF THE WAVE

AXIS NEAR 8N30W...BUT IT APPEARS EMBEDDED WITHIN THE ITCZ.

ISOLATED MODERATE CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE

WAVE AXIS FROM 7N-9N.

I would'nt expect any develpment from this, but this one has the most potential at the moment.

[crimsone]

Shouldn't that be in the troical wave thread rather than the invest thread? I got all excited then for a moment, and then was quite dissapointed! :lol:

Edited June 16, 2008 by crimsone

[Cookie]

join the club :lol:

[Gray-Wolf]

There might not be a future in this 'wave' (east of Windward) but the train is now starting to trundle off Africa with another possible area of interest just plopping into the Atlantic right now.

[kold weather]

Yep whilst the wave does appear to have a certain amount of cyclonic turning indicating some sort of circulation there is dry stable air to its north which appears to be nulling any convection that tries to develop with the wave at least on the northern part of the wave axis anyway. On top of that its about to run into 30-40kts of shear which will finish off the wave I'd imagine in about 36-48hrs time.

Still yep there have been a couple of decent waves which has had presistant convection even out to 50-60W which you wouldn't expect to start seeing in any great numbers till mid July usually so I suspect the wave train is a little more advanced then where it should be, could also be a sign of a more active Cape Verde season then we have seen in recent years. Still a little early for these waves to develop but once we reach late July then we will really have to keep a eye out on these waves.

[tinybill]

Yep whilst the wave does appear to have a certain amount of cyclonic turning indicating some sort of circulation there is dry stable air to its north which appears to be nulling any convection that tries to develop with the wave at least on the northern part of the wave axis anyway. On top of that its about to run into 30-40kts of shear which will finish off the wave I'd imagine in about 36-48hrs time.

Still yep there have been a couple of decent waves which has had persistent convection even out to 50-60W which you wouldn't expect to start seeing in any great numbers till mid July usually so I suspect the wave train is a little more advanced then where it should be, could also be a sign of a more active Cape Verde season then we have seen in recent years. Still a little early for these waves to develop but once we reach late July then we will really have to keep a eye out on these waves.

http://ralphstropicalweather.homestead.com...WeatherOut.html

on here the 1 st tropic wave looks interesting

Edited June 18, 2008 by tinybill